/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 25 by nigel, Sat Feb 24 21:38:45 2007 UTC revision 147 by ph10, Mon Apr 16 13:24:37 2007 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.1 12-Mar-07
5    ---------------------
6    
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other Autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
11    
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
18    
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The 132html script that I use to generate
25        HTML has been updated to handle .nf/.fi and to complain if it encounters
26        .br or .in.
27    
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, with the name
30        config.h.generic, for the benefit of those who have to compile without
31        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
32    
33     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
34        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
35        makevp.bat for the current PCRE, using the additional files
36        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
37    
38     6. A Windows user reported a minor discrepancy with test 2, which turned out
39        to be caused by a trailing space on an input line that had got lost in his
40        copy. The trailing space was an accident, so I've just removed it.
41    
42     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
43        that is needed.
44    
45     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
46        as "const" (a) because they are and (b) because it helps the PHP
47        maintainers who have recently made a script to detect big data structures
48        in the php code that should be moved to the .rodata section. I remembered
49        to update Builducptable as well, so it won't revert if ucptable.h is ever
50        re-created.
51    
52     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
53        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
54        order to be able to cut out the UTF-8 tables in the latter when UTF-8
55        support is not required. This saves 1.5-2K of code, which is important in
56        some applications.
57    
58        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
59        so as not to refer to the tables, even though these functions will never be
60        called when UTF-8 support is disabled. Otherwise there are problems with a
61        shared library.
62    
63    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
64    
65        (a) It was defining its arguments as char * instead of void *.
66    
67        (b) It was assuming that all moves were upwards in memory; this was true
68            a long time ago when I wrote it, but is no longer the case.
69    
70        The emulated memove() is provided for those environments that have neither
71        memmove() nor bcopy(). I didn't think anyone used it these days, but that
72        is clearly not the case, as these two bugs were recently reported.
73    
74    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
75        and Detrail to create the HTML documentation, the .txt form of the man
76        pages, and it removes trailing spaces from listed files. It also creates
77        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
78        case, it wraps all the #defines with #ifndefs. This script should be run
79        before "make dist".
80    
81    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
82        with Unicode property support.
83    
84        (a) For a maximizing quantifier, if the two different cases of the
85            character were of different lengths in their UTF-8 codings (there are
86            some cases like this - I found 11), and the matching function had to
87            back up over a mixture of the two cases, it incorrectly assumed they
88            were both the same length.
89    
90        (b) When PCRE was configured to use the heap rather than the stack for
91            recursion during matching, it was not correctly preserving the data for
92            the other case of a UTF-8 character when checking ahead for a match
93            while processing a minimizing repeat. If the check also involved
94            matching a wide character, but failed, corruption could cause an
95            erroneous result when trying to check for a repeat of the original
96            character.
97    
98    13. Some tidying changes to the testing mechanism:
99    
100        (a) The RunTest script now detects the internal link size and whether there
101            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
102            values substituted by "configure". (The RunGrepTest script already did
103            this for UTF-8.) The configure.ac script no longer substitutes the
104            relevant variables.
105    
106        (b) The debugging options /B and /D in pcretest show the compiled bytecode
107            with length and offset values. This means that the output is different
108            for different internal link sizes. Test 2 is skipped for link sizes
109            other than 2 because of this, bypassing the problem. Unfortunately,
110            there was also a test in test 3 (the locale tests) that used /B and
111            failed for link sizes other than 2. Rather than cut the whole test out,
112            I have added a new /Z option to pcretest that replaces the length and
113            offset values with spaces. This is now used to make test 3 independent
114            of link size. (Test 2 will be tidied up later.)
115    
116    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
117        segmentation fault instead of returning the appropriate error message.
118    
119    15. In multiline mode when the newline sequence was set to "any", the pattern
120        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
121        This doesn't seem right; it now treats the CRLF combination as the line
122        ending, and so does not match in that case. It's only a pattern such as ^$
123        that would hit this one: something like ^ABC$ would have failed after \r
124        and then tried again after \r\n.
125    
126    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
127        in an attempt to make files that differ only in their line terminators
128        compare equal. This works on Linux.
129    
130    17. Under certain error circumstances pcregrep might try to free random memory
131        as it exited. This is now fixed, thanks to valgrind.
132    
133    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
134        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
135        was because its rules for how to advance for /g after matching an empty
136        string at the end of a line did not allow for this case. They now check for
137        it specially.
138    
139    20. pcretest is supposed to handle patterns and data of any length, by
140        extending its buffers when necessary. It was getting this wrong when the
141        buffer for a data line had to be extended.
142    
143    
144    Version 7.0 19-Dec-06
145    ---------------------
146    
147     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
148        moving to gcc 4.1.1.
149    
150     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
151        sys/time.h, which is documented as needed for this function. It doesn't
152        seem to matter on Linux, but it showed up on some releases of OS X.
153    
154     3. It seems that there are systems where bytes whose values are greater than
155        127 match isprint() in the "C" locale. The "C" locale should be the
156        default when a C program starts up. In most systems, only ASCII printing
157        characters match isprint(). This difference caused the output from pcretest
158        to vary, making some of the tests fail. I have changed pcretest so that:
159    
160        (a) When it is outputting text in the compiled version of a pattern, bytes
161            other than 32-126 are always shown as hex escapes.
162    
163        (b) When it is outputting text that is a matched part of a subject string,
164            it does the same, unless a different locale has been set for the match
165            (using the /L modifier). In this case, it uses isprint() to decide.
166    
167     4. Fixed a major bug that caused incorrect computation of the amount of memory
168        required for a compiled pattern when options that changed within the
169        pattern affected the logic of the preliminary scan that determines the
170        length. The relevant options are -x, and -i in UTF-8 mode. The result was
171        that the computed length was too small. The symptoms of this bug were
172        either the PCRE error "internal error: code overflow" from pcre_compile(),
173        or a glibc crash with a message such as "pcretest: free(): invalid next
174        size (fast)". Examples of patterns that provoked this bug (shown in
175        pcretest format) are:
176    
177          /(?-x: )/x
178          /(?x)(?-x: \s*#\s*)/
179          /((?i)[\x{c0}])/8
180          /(?i:[\x{c0}])/8
181    
182        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
183        is now done differently.
184    
185     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
186        wrapper classes; (b) implement a new function in the C++ scanner that is
187        more efficient than the old way of doing things because it avoids levels of
188        recursion in the regex matching; (c) add a paragraph to the documentation
189        for the FullMatch() function.
190    
191     6. The escape sequence \n was being treated as whatever was defined as
192        "newline". Not only was this contrary to the documentation, which states
193        that \n is character 10 (hex 0A), but it also went horribly wrong when
194        "newline" was defined as CRLF. This has been fixed.
195    
196     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
197        was being set to -1 for the "end of line" case (supposedly a value that no
198        character can have). Though this value is never used (the check for end of
199        line is "zero bytes in current character"), it caused compiler complaints.
200        I've changed it to 0xffffffff.
201    
202     8. In pcre_version.c, the version string was being built by a sequence of
203        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
204        string (as it is for production releases) called a macro with an empty
205        argument. The C standard says the result of this is undefined. The gcc
206        compiler treats it as an empty string (which was what was wanted) but it is
207        reported that Visual C gives an error. The source has been hacked around to
208        avoid this problem.
209    
210     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
211        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
212        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
213        of them did).
214    
215    10. Originally, pcretest opened its input and output without "b"; then I was
216        told that "b" was needed in some environments, so it was added for release
217        5.0 to both the input and output. (It makes no difference on Unix-like
218        systems.) Later I was told that it is wrong for the input on Windows. I've
219        now abstracted the modes into two macros, to make it easier to fiddle with
220        them, and removed "b" from the input mode under Windows.
221    
222    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
223    
224    12. Added -help and --help to pcretest as an official way of being reminded
225        of the options.
226    
227    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
228        and pcrecpp.cc because they annoy compilers at high warning levels.
229    
230    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
231    
232    15. Fixed an occurrence of == in configure.ac that should have been = (shell
233        scripts are not C programs :-) and which was not noticed because it works
234        on Linux.
235    
236    16. pcretest is supposed to handle any length of pattern and data line (as one
237        line or as a continued sequence of lines) by extending its input buffer if
238        necessary. This feature was broken for very long pattern lines, leading to
239        a string of junk being passed to pcre_compile() if the pattern was longer
240        than about 50K.
241    
242    17. I have done a major re-factoring of the way pcre_compile() computes the
243        amount of memory needed for a compiled pattern. Previously, there was code
244        that made a preliminary scan of the pattern in order to do this. That was
245        OK when PCRE was new, but as the facilities have expanded, it has become
246        harder and harder to keep it in step with the real compile phase, and there
247        have been a number of bugs (see for example, 4 above). I have now found a
248        cunning way of running the real compile function in a "fake" mode that
249        enables it to compute how much memory it would need, while actually only
250        ever using a few hundred bytes of working memory and without too many
251        tests of the mode. This should make future maintenance and development
252        easier. A side effect of this work is that the limit of 200 on the nesting
253        depth of parentheses has been removed (though this was never a serious
254        limitation, I suspect). However, there is a downside: pcre_compile() now
255        runs more slowly than before (30% or more, depending on the pattern). I
256        hope this isn't a big issue. There is no effect on runtime performance.
257    
258    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
259        newline (only possible for the last line of a file) and it was a
260        pattern that set a locale (followed by /Lsomething), pcretest crashed.
261    
262    19. Added additional timing features to pcretest. (1) The -tm option now times
263        matching only, not compiling. (2) Both -t and -tm can be followed, as a
264        separate command line item, by a number that specifies the number of
265        repeats to use when timing. The default is 50000; this gives better
266        precision, but takes uncomfortably long for very large patterns.
267    
268    20. Extended pcre_study() to be more clever in cases where a branch of a
269        subpattern has no definite first character. For example, (a*|b*)[cd] would
270        previously give no result from pcre_study(). Now it recognizes that the
271        first character must be a, b, c, or d.
272    
273    21. There was an incorrect error "recursive call could loop indefinitely" if
274        a subpattern (or the entire pattern) that was being tested for matching an
275        empty string contained only one non-empty item after a nested subpattern.
276        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
277        incorrectly, because the \d was being skipped in the check.
278    
279    22. The pcretest program now has a new pattern option /B and a command line
280        option -b, which is equivalent to adding /B to every pattern. This causes
281        it to show the compiled bytecode, without the additional information that
282        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
283        is the same as /B/I).
284    
285    23. A new optimization is now able automatically to treat some sequences such
286        as a*b as a*+b. More specifically, if something simple (such as a character
287        or a simple class like \d) has an unlimited quantifier, and is followed by
288        something that cannot possibly match the quantified thing, the quantifier
289        is automatically "possessified".
290    
291    24. A recursive reference to a subpattern whose number was greater than 39
292        went wrong under certain circumstances in UTF-8 mode. This bug could also
293        have affected the operation of pcre_study().
294    
295    25. Realized that a little bit of performance could be had by replacing
296        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
297    
298    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
299    
300    27. Possessive quantifiers such as a++ were previously implemented by turning
301        them into atomic groups such as ($>a+). Now they have their own opcodes,
302        which improves performance. This includes the automatically created ones
303        from 23 above.
304    
305    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
306        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
307        the first matched character to be a colon. This applied both to named and
308        numbered groups.
309    
310    29. The ucpinternal.h header file was missing its idempotency #ifdef.
311    
312    30. I was sent a "project" file called libpcre.a.dev which I understand makes
313        building PCRE on Windows easier, so I have included it in the distribution.
314    
315    31. There is now a check in pcretest against a ridiculously large number being
316        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
317        loop, the loop is abandoned.
318    
319    32. Forward references to subpatterns in conditions such as (?(2)...) where
320        subpattern 2 is defined later cause pcre_compile() to search forwards in
321        the pattern for the relevant set of parentheses. This search went wrong
322        when there were unescaped parentheses in a character class, parentheses
323        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
324    
325    33. "Subroutine" calls and backreferences were previously restricted to
326        referencing subpatterns earlier in the regex. This restriction has now
327        been removed.
328    
329    34. Added a number of extra features that are going to be in Perl 5.10. On the
330        whole, these are just syntactic alternatives for features that PCRE had
331        previously implemented using the Python syntax or my own invention. The
332        other formats are all retained for compatibility.
333    
334        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
335            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
336            also .NET compatible.
337    
338        (b) A recursion or subroutine call to a named group can now be defined as
339            (?&name) as well as (?P>name).
340    
341        (c) A backreference to a named group can now be defined as \k<name> or
342            \k'name' as well as (?P=name). The new forms, as well as being in Perl
343            5.10, are also .NET compatible.
344    
345        (d) A conditional reference to a named group can now use the syntax
346            (?(<name>) or (?('name') as well as (?(name).
347    
348        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
349            groups (named and numbered) that are never evaluated inline, but can be
350            called as "subroutines" from elsewhere. In effect, the DEFINE condition
351            is always false. There may be only one alternative in such a group.
352    
353        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
354            as the simple (?(R). The condition is true only if the most recent
355            recursion is that of the given number or name. It does not search out
356            through the entire recursion stack.
357    
358        (g) The escape \gN or \g{N} has been added, where N is a positive or
359            negative number, specifying an absolute or relative reference.
360    
361    35. Tidied to get rid of some further signed/unsigned compiler warnings and
362        some "unreachable code" warnings.
363    
364    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
365        things, this adds five new scripts.
366    
367    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
368        There were also incompatibilities regarding the handling of \Q..\E inside
369        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
370        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
371    
372    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
373        matches an empty string, and forcibly breaks the loop. There were bugs in
374        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
375        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
376        separate and independent bugs (that affected different cases) have been
377        fixed.
378    
379    39. Refactored the code to abolish the use of different opcodes for small
380        capturing bracket numbers. This is a tidy that I avoided doing when I
381        removed the limit on the number of capturing brackets for 3.5 back in 2001.
382        The new approach is not only tidier, it makes it possible to reduce the
383        memory needed to fix the previous bug (38).
384    
385    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
386        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
387        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
388        mode.
389    
390    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
391        report.
392    
393    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
394        copy construction and assignment in the C++ wrapper.
395    
396    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
397        couple of bugs that could have given wrong results in the "--newline=crlf"
398        case.
399    
400    44. Added a number of casts and did some reorganization of signed/unsigned int
401        variables following suggestions from Dair Grant. Also renamed the variable
402        "this" as "item" because it is a C++ keyword.
403    
404    45. Arranged for dftables to add
405    
406          #include "pcre_internal.h"
407    
408        to pcre_chartables.c because without it, gcc 4.x may remove the array
409        definition from the final binary if PCRE is built into a static library and
410        dead code stripping is activated.
411    
412    46. For an unanchored pattern, if a match attempt fails at the start of a
413        newline sequence, and the newline setting is CRLF or ANY, and the next two
414        characters are CRLF, advance by two characters instead of one.
415    
416    
417    Version 6.7 04-Jul-06
418    ---------------------
419    
420     1. In order to handle tests when input lines are enormously long, pcretest has
421        been re-factored so that it automatically extends its buffers when
422        necessary. The code is crude, but this _is_ just a test program. The
423        default size has been increased from 32K to 50K.
424    
425     2. The code in pcre_study() was using the value of the re argument before
426        testing it for NULL. (Of course, in any sensible call of the function, it
427        won't be NULL.)
428    
429     3. The memmove() emulation function in pcre_internal.h, which is used on
430        systems that lack both memmove() and bcopy() - that is, hardly ever -
431        was missing a "static" storage class specifier.
432    
433     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
434        containing an extended class (one that cannot be represented by a bitmap
435        because it contains high-valued characters or Unicode property items, e.g.
436        [\pZ]). Almost always one would set UTF-8 mode when processing such a
437        pattern, but PCRE should not loop if you do not (it no longer does).
438        [Detail: two cases were found: (a) a repeated subpattern containing an
439        extended class; (b) a recursive reference to a subpattern that followed a
440        previous extended class. It wasn't skipping over the extended class
441        correctly when UTF-8 mode was not set.]
442    
443     5. A negated single-character class was not being recognized as fixed-length
444        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
445        compile error "lookbehind assertion is not fixed length".
446    
447     6. The RunPerlTest auxiliary script was showing an unexpected difference
448        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
449        write a Perl script that can interpret lines of an input file either as
450        byte characters or as UTF-8, which is what "perltest" was being required to
451        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
452        can't do is switch easily at run time between having the "use utf8;" pragma
453        or not. In the end, I fudged it by using the RunPerlTest script to insert
454        "use utf8;" explicitly for the UTF-8 tests.
455    
456     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
457        the end of the subject string, contrary to the documentation and to what
458        Perl does. This was true of both matching functions. Now it matches only at
459        the start of the subject and immediately after *internal* newlines.
460    
461     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
462        a pointer to an int instead of a pointer to an unsigned long int. This
463        caused problems on 64-bit systems.
464    
465     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
466        instance of the 'standard' template library not being so standard".
467    
468    10. There was no check on the number of named subpatterns nor the maximum
469        length of a subpattern name. The product of these values is used to compute
470        the size of the memory block for a compiled pattern. By supplying a very
471        long subpattern name and a large number of named subpatterns, the size
472        computation could be caused to overflow. This is now prevented by limiting
473        the length of names to 32 characters, and the number of named subpatterns
474        to 10,000.
475    
476    11. Subpatterns that are repeated with specific counts have to be replicated in
477        the compiled pattern. The size of memory for this was computed from the
478        length of the subpattern and the repeat count. The latter is limited to
479        65535, but there was no limit on the former, meaning that integer overflow
480        could in principle occur. The compiled length of a repeated subpattern is
481        now limited to 30,000 bytes in order to prevent this.
482    
483    12. Added the optional facility to have named substrings with the same name.
484    
485    13. Added the ability to use a named substring as a condition, using the
486        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
487        are numbers (not recommended). Forward references are permitted.
488    
489    14. Added forward references in named backreferences (if you see what I mean).
490    
491    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
492        pattern could run off the end of the subject. For example, the pattern
493        "(?s)(.{1,5})"8 did this with the subject "ab".
494    
495    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
496        PCRE_CASELESS was set when matching characters that were quantified with ?
497        or *.
498    
499    17. A character class other than a single negated character that had a minimum
500        but no maximum quantifier - for example [ab]{6,} - was not handled
501        correctly by pce_dfa_exec(). It would match only one character.
502    
503    18. A valid (though odd) pattern that looked like a POSIX character
504        class but used an invalid character after [ (for example [[,abc,]]) caused
505        pcre_compile() to give the error "Failed: internal error: code overflow" or
506        in some cases to crash with a glibc free() error. This could even happen if
507        the pattern terminated after [[ but there just happened to be a sequence of
508        letters, a binary zero, and a closing ] in the memory that followed.
509    
510    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
511        over the years. Originally (before any Unicode support), just the bottom 8
512        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
513        output from "man perlunicode" includes this:
514    
515          The regular expression compiler produces polymorphic opcodes.  That
516          is, the pattern adapts to the data and automatically switches to
517          the Unicode character scheme when presented with Unicode data--or
518          instead uses a traditional byte scheme when presented with byte
519          data.
520    
521        Sadly, a wide octal escape does not cause a switch, and in a string with
522        no other multibyte characters, these octal escapes are treated as before.
523        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
524        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
525        Unicode string.
526    
527        I have not perpetrated such confusion in PCRE. Up till now, it took just
528        the bottom 8 bits, as in old Perl. I have now made octal escapes with
529        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
530        translate to the appropriate multibyte character.
531    
532    29. Applied some refactoring to reduce the number of warnings from Microsoft
533        and Borland compilers. This has included removing the fudge introduced
534        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
535        a warning about an unused variable.
536    
537    21. PCRE has not included VT (character 0x0b) in the set of whitespace
538        characters since release 4.0, because Perl (from release 5.004) does not.
539        [Or at least, is documented not to: some releases seem to be in conflict
540        with the documentation.] However, when a pattern was studied with
541        pcre_study() and all its branches started with \s, PCRE still included VT
542        as a possible starting character. Of course, this did no harm; it just
543        caused an unnecessary match attempt.
544    
545    22. Removed a now-redundant internal flag bit that recorded the fact that case
546        dependency changed within the pattern. This was once needed for "required
547        byte" processing, but is no longer used. This recovers a now-scarce options
548        bit. Also moved the least significant internal flag bit to the most-
549        significant bit of the word, which was not previously used (hangover from
550        the days when it was an int rather than a uint) to free up another bit for
551        the future.
552    
553    23. Added support for CRLF line endings as well as CR and LF. As well as the
554        default being selectable at build time, it can now be changed at runtime
555        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
556        specify that it is scanning data with non-default line endings.
557    
558    24. Changed the definition of CXXLINK to make it agree with the definition of
559        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
560    
561    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
562        recursions. This makes a big different to stack usage for some patterns.
563    
564    26. If a subpattern containing a named recursion or subroutine reference such
565        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
566        the space required for the compiled pattern went wrong and gave too small a
567        value. Depending on the environment, this could lead to "Failed: internal
568        error: code overflow at offset 49" or "glibc detected double free or
569        corruption" errors.
570    
571    27. Applied patches from Google (a) to support the new newline modes and (b) to
572        advance over multibyte UTF-8 characters in GlobalReplace.
573    
574    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
575        difference for some implementation of PCRE in some Windows version.
576    
577    29. Added some extra testing facilities to pcretest:
578    
579        \q<number>   in a data line sets the "match limit" value
580        \Q<number>   in a data line sets the "match recursion limt" value
581        -S <number>  sets the stack size, where <number> is in megabytes
582    
583        The -S option isn't available for Windows.
584    
585    
586    Version 6.6 06-Feb-06
587    ---------------------
588    
589     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
590        in pcreposix.h. I have copied the definition from pcre.h.
591    
592     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
593        because pcre.h is no longer a built file.
594    
595     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
596        not normally included in the compiled code.
597    
598    
599    Version 6.5 01-Feb-06
600    ---------------------
601    
602     1. When using the partial match feature with pcre_dfa_exec(), it was not
603        anchoring the second and subsequent partial matches at the new starting
604        point. This could lead to incorrect results. For example, with the pattern
605        /1234/, partially matching against "123" and then "a4" gave a match.
606    
607     2. Changes to pcregrep:
608    
609        (a) All non-match returns from pcre_exec() were being treated as failures
610            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
611            error message is output. Some extra information is given for the
612            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
613            probably the only errors that are likely to be caused by users (by
614            specifying a regex that has nested indefinite repeats, for instance).
615            If there are more than 20 of these errors, pcregrep is abandoned.
616    
617        (b) A binary zero was treated as data while matching, but terminated the
618            output line if it was written out. This has been fixed: binary zeroes
619            are now no different to any other data bytes.
620    
621        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
622            used to set a locale for matching. The --locale=xxxx long option has
623            been added (no short equivalent) to specify a locale explicitly on the
624            pcregrep command, overriding the environment variables.
625    
626        (d) When -B was used with -n, some line numbers in the output were one less
627            than they should have been.
628    
629        (e) Added the -o (--only-matching) option.
630    
631        (f) If -A or -C was used with -c (count only), some lines of context were
632            accidentally printed for the final match.
633    
634        (g) Added the -H (--with-filename) option.
635    
636        (h) The combination of options -rh failed to suppress file names for files
637            that were found from directory arguments.
638    
639        (i) Added the -D (--devices) and -d (--directories) options.
640    
641        (j) Added the -F (--fixed-strings) option.
642    
643        (k) Allow "-" to be used as a file name for -f as well as for a data file.
644    
645        (l) Added the --colo(u)r option.
646    
647        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
648            is not present by default.
649    
650     3. A nasty bug was discovered in the handling of recursive patterns, that is,
651        items such as (?R) or (?1), when the recursion could match a number of
652        alternatives. If it matched one of the alternatives, but subsequently,
653        outside the recursion, there was a failure, the code tried to back up into
654        the recursion. However, because of the way PCRE is implemented, this is not
655        possible, and the result was an incorrect result from the match.
656    
657        In order to prevent this happening, the specification of recursion has
658        been changed so that all such subpatterns are automatically treated as
659        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
660    
661     4. I had overlooked the fact that, in some locales, there are characters for
662        which isalpha() is true but neither isupper() nor islower() are true. In
663        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
664        and ordfeminine) are like this. This affected the treatment of \w and \W
665        when they appeared in character classes, but not when they appeared outside
666        a character class. The bit map for "word" characters is now created
667        separately from the results of isalnum() instead of just taking it from the
668        upper, lower, and digit maps. (Plus the underscore character, of course.)
669    
670     5. The above bug also affected the handling of POSIX character classes such as
671        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
672        permanent tables. Instead, the bit maps for such a class were previously
673        created as the appropriate unions of the upper, lower, and digit bitmaps.
674        Now they are created by subtraction from the [[:word:]] class, which has
675        its own bitmap.
676    
677     6. The [[:blank:]] character class matches horizontal, but not vertical space.
678        It is created by subtracting the vertical space characters (\x09, \x0a,
679        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
680        subtraction was done in the overall bitmap for a character class, meaning
681        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
682        be recognized. This bug has been fixed.
683    
684     7. Patches from the folks at Google:
685    
686          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
687          real life, but is still worth protecting against".
688    
689          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
690          regular expressions".
691    
692          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
693          have it.
694    
695          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
696          "configure" and the latter not, in order to fix a problem somebody had
697          with compiling the Arg class on HP-UX.
698    
699          (e) Improve the error-handling of the C++ wrapper a little bit.
700    
701          (f) New tests for checking recursion limiting.
702    
703     8. The pcre_memmove() function, which is used only if the environment does not
704        have a standard memmove() function (and is therefore rarely compiled),
705        contained two bugs: (a) use of int instead of size_t, and (b) it was not
706        returning a result (though PCRE never actually uses the result).
707    
708     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
709        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
710        returned instead of calling malloc() with an overflowing number that would
711        most likely cause subsequent chaos.
712    
713    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
714    
715    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
716        with this option is matched, the nmatch and pmatch options of regexec() are
717        ignored.
718    
719    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
720        provided in case anyone wants to the the POSIX interface with UTF-8
721        strings.
722    
723    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
724        C++ linking (needed for some HP-UX environments).
725    
726    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
727        (unused parameter) and in the pcre_printint() function (omitted "default"
728        switch label when the default is to do nothing).
729    
730    15. Added some code to make it possible, when PCRE is compiled as a C++
731        library, to replace subject pointers for pcre_exec() with a smart pointer
732        class, thus making it possible to process discontinuous strings.
733    
734    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
735        much the same function. They were added by different people who were trying
736        to make PCRE easy to compile on non-Unix systems. It has been suggested
737        that PCRE_EXPORT be abolished now that there is more automatic apparatus
738        for compiling on Windows systems. I have therefore replaced it with
739        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
740        defaults to "extern" for C or "extern C" for C++, which works fine on
741        Unix-like systems. It is now possible to override the value of PCRE_DATA_
742        SCOPE with something explicit in config.h. In addition:
743    
744        (a) pcreposix.h still had just "extern" instead of either of these macros;
745            I have replaced it with PCRE_DATA_SCOPE.
746    
747        (b) Functions such as _pcre_xclass(), which are internal to the library,
748            but external in the C sense, all had PCRE_EXPORT in their definitions.
749            This is apparently wrong for the Windows case, so I have removed it.
750            (It makes no difference on Unix-like systems.)
751    
752    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
753        of recursive calls to match(). This is different to MATCH_LIMIT because
754        that limits the total number of calls to match(), not all of which increase
755        the depth of recursion. Limiting the recursion depth limits the amount of
756        stack (or heap if NO_RECURSE is set) that is used. The default can be set
757        when PCRE is compiled, and changed at run time. A patch from Google adds
758        this functionality to the C++ interface.
759    
760    18. Changes to the handling of Unicode character properties:
761    
762        (a) Updated the table to Unicode 4.1.0.
763    
764        (b) Recognize characters that are not in the table as "Cn" (undefined).
765    
766        (c) I revised the way the table is implemented to a much improved format
767            which includes recognition of ranges. It now supports the ranges that
768            are defined in UnicodeData.txt, and it also amalgamates other
769            characters into ranges. This has reduced the number of entries in the
770            table from around 16,000 to around 3,000, thus reducing its size
771            considerably. I realized I did not need to use a tree structure after
772            all - a binary chop search is just as efficient. Having reduced the
773            number of entries, I extended their size from 6 bytes to 8 bytes to
774            allow for more data.
775    
776        (d) Added support for Unicode script names via properties such as \p{Han}.
777    
778    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
779        matching that character.
780    
781    20. When matching a repeated Unicode property with a minimum greater than zero,
782        (for example \pL{2,}), PCRE could look past the end of the subject if it
783        reached it while seeking the minimum number of characters. This could
784        happen only if some of the characters were more than one byte long, because
785        there is a check for at least the minimum number of bytes.
786    
787    21. Refactored the implementation of \p and \P so as to be more general, to
788        allow for more different types of property in future. This has changed the
789        compiled form incompatibly. Anybody with saved compiled patterns that use
790        \p or \P will have to recompile them.
791    
792    22. Added "Any" and "L&" to the supported property types.
793    
794    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
795        but give a compile time error if the value is greater than 0xff.
796    
797    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
798        accidentally not being installed or uninstalled.
799    
800    25. The pcre.h file was built from pcre.h.in, but the only changes that were
801        made were to insert the current release number. This seemed silly, because
802        it made things harder for people building PCRE on systems that don't run
803        "configure". I have turned pcre.h into a distributed file, no longer built
804        by "configure", with the version identification directly included. There is
805        no longer a pcre.h.in file.
806    
807        However, this change necessitated a change to the pcre-config script as
808        well. It is built from pcre-config.in, and one of the substitutions was the
809        release number. I have updated configure.ac so that ./configure now finds
810        the release number by grepping pcre.h.
811    
812    26. Added the ability to run the tests under valgrind.
813    
814    
815    Version 6.4 05-Sep-05
816    ---------------------
817    
818     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
819        "--" to be printed when multiple files were scanned, even when none of the
820        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
821        consider it to be a bug, and have restored the previous behaviour.
822    
823     2. A couple of code tidies to get rid of compiler warnings.
824    
825     3. The pcretest program used to cheat by referring to symbols in the library
826        whose names begin with _pcre_. These are internal symbols that are not
827        really supposed to be visible externally, and in some environments it is
828        possible to suppress them. The cheating is now confined to including
829        certain files from the library's source, which is a bit cleaner.
830    
831     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
832        file's purpose clearer.
833    
834     5. Reorganized pcre_ucp_findchar().
835    
836    
837    Version 6.3 15-Aug-05
838    ---------------------
839    
840     1. The file libpcre.pc.in did not have general read permission in the tarball.
841    
842     2. There were some problems when building without C++ support:
843    
844        (a) If C++ support was not built, "make install" and "make test" still
845            tried to test it.
846    
847        (b) There were problems when the value of CXX was explicitly set. Some
848            changes have been made to try to fix these, and ...
849    
850        (c) --disable-cpp can now be used to explicitly disable C++ support.
851    
852        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
853            backslash in a target when C++ was disabled. This confuses some
854            versions of "make", apparently. Using an intermediate variable solves
855            this. (Same for CPP_LOBJ.)
856    
857     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
858        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
859        necessary on certain architectures.
860    
861     4. Added a setting of -export-symbols-regex to the link command to remove
862        those symbols that are exported in the C sense, but actually are local
863        within the library, and not documented. Their names all begin with
864        "_pcre_". This is not a perfect job, because (a) we have to except some
865        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
866        available (and never for static libraries). I have made a note to try to
867        find a way round (a) in the future.
868    
869    
870    Version 6.2 01-Aug-05
871    ---------------------
872    
873     1. There was no test for integer overflow of quantifier values. A construction
874        such as {1111111111111111} would give undefined results. What is worse, if
875        a minimum quantifier for a parenthesized subpattern overflowed and became
876        negative, the calculation of the memory size went wrong. This could have
877        led to memory overwriting.
878    
879     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
880    
881     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
882        operating environments where this matters.
883    
884     4. Applied Giuseppe Maxia's patch to add additional features for controlling
885        PCRE options from within the C++ wrapper.
886    
887     5. Named capturing subpatterns were not being correctly counted when a pattern
888        was compiled. This caused two problems: (a) If there were more than 100
889        such subpatterns, the calculation of the memory needed for the whole
890        compiled pattern went wrong, leading to an overflow error. (b) Numerical
891        back references of the form \12, where the number was greater than 9, were
892        not recognized as back references, even though there were sufficient
893        previous subpatterns.
894    
895     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
896        versions of gcc, e.g. 2.95.4.
897    
898    
899    Version 6.1 21-Jun-05
900    ---------------------
901    
902     1. There was one reference to the variable "posix" in pcretest.c that was not
903        surrounded by "#if !defined NOPOSIX".
904    
905     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
906        the cross-check on the old pcre_info() function, for the benefit of the
907        cut-down version of PCRE that is currently imported into Exim.
908    
909     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
910        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
911        patterns that start (?i) but I don't think that matters. The use of (?i) is
912        just an example; this all applies to the other options as well.
913    
914     4. Since libtool seems to echo the compile commands it is issuing, the output
915        from "make" can be reduced a bit by putting "@" in front of each libtool
916        compile command.
917    
918     5. Patch from the folks at Google for configure.in to be a bit more thorough
919        in checking for a suitable C++ installation before trying to compile the
920        C++ stuff. This should fix a reported problem when a compiler was present,
921        but no suitable headers.
922    
923     6. The man pages all had just "PCRE" as their title. I have changed them to
924        be the relevant file name. I have also arranged that these names are
925        retained in the file doc/pcre.txt, which is a concatenation in text format
926        of all the man pages except the little individual ones for each function.
927    
928     7. The NON-UNIX-USE file had not been updated for the different set of source
929        files that come with release 6. I also added a few comments about the C++
930        wrapper.
931    
932    
933    Version 6.0 07-Jun-05
934    ---------------------
935    
936     1. Some minor internal re-organization to help with my DFA experiments.
937    
938     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
939        didn't matter for the library itself when fully configured, but did matter
940        when compiling without UCP support, or within Exim, where the ucp files are
941        not imported.
942    
943     3. Refactoring of the library code to split up the various functions into
944        different source modules. The addition of the new DFA matching code (see
945        below) to a single monolithic source would have made it really too
946        unwieldy, quite apart from causing all the code to be include in a
947        statically linked application, when only some functions are used. This is
948        relevant even without the DFA addition now that patterns can be compiled in
949        one application and matched in another.
950    
951        The downside of splitting up is that there have to be some external
952        functions and data tables that are used internally in different modules of
953        the library but which are not part of the API. These have all had their
954        names changed to start with "_pcre_" so that they are unlikely to clash
955        with other external names.
956    
957     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
958        a different (DFA) algorithm. Although it is slower than the original
959        function, it does have some advantages for certain types of matching
960        problem.
961    
962     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
963        including restarting after a partial match.
964    
965     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
966        defined when compiling for Windows was sent to me. I have put it into the
967        code, though I have no means of testing or verifying it.
968    
969     7. Added the pcre_refcount() auxiliary function.
970    
971     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
972        match before or at the first newline in the subject string. In pcretest,
973        the /f option on a pattern can be used to set this.
974    
975     9. A repeated \w when used in UTF-8 mode with characters greater than 256
976        would behave wrongly. This has been present in PCRE since release 4.0.
977    
978    10. A number of changes to the pcregrep command:
979    
980        (a) Refactored how -x works; insert ^(...)$ instead of setting
981            PCRE_ANCHORED and checking the length, in preparation for adding
982            something similar for -w.
983    
984        (b) Added the -w (match as a word) option.
985    
986        (c) Refactored the way lines are read and buffered so as to have more
987            than one at a time available.
988    
989        (d) Implemented a pcregrep test script.
990    
991        (e) Added the -M (multiline match) option. This allows patterns to match
992            over several lines of the subject. The buffering ensures that at least
993            8K, or the rest of the document (whichever is the shorter) is available
994            for matching (and similarly the previous 8K for lookbehind assertions).
995    
996        (f) Changed the --help output so that it now says
997    
998              -w, --word-regex(p)
999    
1000            instead of two lines, one with "regex" and the other with "regexp"
1001            because that confused at least one person since the short forms are the
1002            same. (This required a bit of code, as the output is generated
1003            automatically from a table. It wasn't just a text change.)
1004    
1005        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1006            option but starts with a hyphen. Could be a pattern or a path name
1007            starting with a hyphen, for instance.
1008    
1009        (h) "-" can be given as a file name to represent stdin.
1010    
1011        (i) When file names are being printed, "(standard input)" is used for
1012            the standard input, for compatibility with GNU grep. Previously
1013            "<stdin>" was used.
1014    
1015        (j) The option --label=xxx can be used to supply a name to be used for
1016            stdin when file names are being printed. There is no short form.
1017    
1018        (k) Re-factored the options decoding logic because we are going to add
1019            two more options that take data. Such options can now be given in four
1020            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1021    
1022        (l) Added the -A, -B, and -C options for requesting that lines of context
1023            around matches be printed.
1024    
1025        (m) Added the -L option to print the names of files that do not contain
1026            any matching lines, that is, the complement of -l.
1027    
1028        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1029            continue to scan other files.
1030    
1031        (o) The -s option was incorrectly implemented. For compatibility with other
1032            greps, it now suppresses the error message for a non-existent or non-
1033            accessible file (but not the return code). There is a new option called
1034            -q that suppresses the output of matching lines, which was what -s was
1035            previously doing.
1036    
1037        (p) Added --include and --exclude options to specify files for inclusion
1038            and exclusion when recursing.
1039    
1040    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1041        Hopefully, it now does.
1042    
1043    12. Missing cast in pcre_study().
1044    
1045    13. Added an "uninstall" target to the makefile.
1046    
1047    14. Replaced "extern" in the function prototypes in Makefile.in with
1048        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1049        world, but is set differently for Windows.
1050    
1051    15. Added a second compiling function called pcre_compile2(). The only
1052        difference is that it has an extra argument, which is a pointer to an
1053        integer error code. When there is a compile-time failure, this is set
1054        non-zero, in addition to the error test pointer being set to point to an
1055        error message. The new argument may be NULL if no error number is required
1056        (but then you may as well call pcre_compile(), which is now just a
1057        wrapper). This facility is provided because some applications need a
1058        numeric error indication, but it has also enabled me to tidy up the way
1059        compile-time errors are handled in the POSIX wrapper.
1060    
1061    16. Added VPATH=.libs to the makefile; this should help when building with one
1062        prefix path and installing with another. (Or so I'm told by someone who
1063        knows more about this stuff than I do.)
1064    
1065    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1066        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1067        match everything, including newlines. This is not POSIX-compatible, but
1068        somebody wanted the feature. From pcretest it can be activated by using
1069        both the P and the s flags.
1070    
1071    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1072    
1073    19. libpcre.pc was being incorrectly installed as executable.
1074    
1075    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1076        it now also looks for '\r' so that it will work unmodified on Windows.
1077    
1078    21. Added Google's contributed C++ wrapper to the distribution.
1079    
1080    22. Added some untidy missing memory free() calls in pcretest, to keep
1081        Electric Fence happy when testing.
1082    
1083    
1084    
1085    Version 5.0 13-Sep-04
1086    ---------------------
1087    
1088     1. Internal change: literal characters are no longer packed up into items
1089        containing multiple characters in a single byte-string. Each character
1090        is now matched using a separate opcode. However, there may be more than one
1091        byte in the character in UTF-8 mode.
1092    
1093     2. The pcre_callout_block structure has two new fields: pattern_position and
1094        next_item_length. These contain the offset in the pattern to the next match
1095        item, and its length, respectively.
1096    
1097     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1098        insertion of callouts before each pattern item. Added the /C option to
1099        pcretest to make use of this.
1100    
1101     4. On the advice of a Windows user, the lines
1102    
1103          #if defined(_WIN32) || defined(WIN32)
1104          _setmode( _fileno( stdout ), 0x8000 );
1105          #endif  /* defined(_WIN32) || defined(WIN32) */
1106    
1107        have been added to the source of pcretest. This apparently does useful
1108        magic in relation to line terminators.
1109    
1110     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1111        for the benefit of those environments where the "b" makes a difference.
1112    
1113     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1114        to know about it. I have put a hack into configure.in that adds in code
1115        to set GCC=yes if CC=icc. This seems to end up at a point in the
1116        generated configure script that is early enough to affect the setting of
1117        compiler options, which is what is needed, but I have no means of testing
1118        whether it really works. (The user who reported this had patched the
1119        generated configure script, which of course I cannot do.)
1120    
1121        LATER: After change 22 below (new libtool files), the configure script
1122        seems to know about icc (and also ecc). Therefore, I have commented out
1123        this hack in configure.in.
1124    
1125     7. Added support for pkg-config (2 patches were sent in).
1126    
1127     8. Negated POSIX character classes that used a combination of internal tables
1128        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1129        [[:^ascii]]. Typically, they would match almost any characters. The other
1130        POSIX classes were not broken in this way.
1131    
1132     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1133        to find the match, as PCRE was deluded into thinking that the match had to
1134        start at the start point or following a newline. The same bug applied to
1135        patterns with negative forward assertions or any backward assertions
1136        preceding ".*" at the start, unless the pattern required a fixed first
1137        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1138    
1139    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1140        starting at the last subject character, bytes beyond the end of the subject
1141        string were read.
1142    
1143    11. Renamed the variable "class" as "classbits" to make life easier for C++
1144        users. (Previously there was a macro definition, but it apparently wasn't
1145        enough.)
1146    
1147    12. Added the new field "tables" to the extra data so that tables can be passed
1148        in at exec time, or the internal tables can be re-selected. This allows
1149        a compiled regex to be saved and re-used at a later time by a different
1150        program that might have everything at different addresses.
1151    
1152    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1153        -R library as well as a -L library.
1154    
1155    14. The debugging options of pcretest (-d on the command line or D on a
1156        pattern) showed incorrect output for anything following an extended class
1157        that contained multibyte characters and which was followed by a quantifier.
1158    
1159    15. Added optional support for general category Unicode character properties
1160        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1161        support. It adds about 90K to the size of the library. The meanings of the
1162        inbuilt class escapes such as \d and \s have NOT been changed.
1163    
1164    16. Updated pcredemo.c to include calls to free() to release the memory for the
1165        compiled pattern.
1166    
1167    17. The generated file chartables.c was being created in the source directory
1168        instead of in the building directory. This caused the build to fail if the
1169        source directory was different from the building directory, and was
1170        read-only.
1171    
1172    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1173        file. No doubt somebody will tell me if they don't make sense... Also added
1174        Dan Mooney's comments about building on OpenVMS.
1175    
1176    19. Added support for partial matching via the PCRE_PARTIAL option for
1177        pcre_exec() and the \P data escape in pcretest.
1178    
1179    20. Extended pcretest with 3 new pattern features:
1180    
1181        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1182              write the compiled pattern to the file whose name is "rest-of-line".
1183              This is a straight binary dump of the data, with the saved pointer to
1184              the character tables forced to be NULL. The study data, if any, is
1185              written too. After writing, pcretest reads a new pattern.
1186    
1187        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1188              compiled pattern from the given file. There must not be any
1189              occurrences of "<" in the file name (pretty unlikely); if there are,
1190              pcretest will instead treat the initial "<" as a pattern delimiter.
1191              After reading in the pattern, pcretest goes on to read data lines as
1192              usual.
1193    
1194        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1195              and 16-bit fields in a compiled pattern, to simulate a pattern that
1196              was compiled on a host of opposite endianness.
1197    
1198    21. The pcre-exec() function can now cope with patterns that were compiled on
1199        hosts of opposite endianness, with this restriction:
1200    
1201          As for any compiled expression that is saved and used later, the tables
1202          pointer field cannot be preserved; the extra_data field in the arguments
1203          to pcre_exec() should be used to pass in a tables address if a value
1204          other than the default internal tables were used at compile time.
1205    
1206    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1207        now diagnosed as an error. Previously, most of the time, a negative number
1208        would have been treated as zero, but if in addition "ovector" was passed as
1209        NULL, a crash could occur.
1210    
1211    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1212        new versions from the libtool 1.5 distribution (the last one is a copy of
1213        a file called libtool.m4). This seems to have fixed the need to patch
1214        "configure" to support Darwin 1.3 (which I used to do). However, I still
1215        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1216        workstation).
1217    
1218    24. Changed the PCRE licence to be the more standard "BSD" licence.
1219    
1220    
1221    Version 4.5 01-Dec-03
1222    ---------------------
1223    
1224     1. There has been some re-arrangement of the code for the match() function so
1225        that it can be compiled in a version that does not call itself recursively.
1226        Instead, it keeps those local variables that need separate instances for
1227        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1228        needs to "recurse". Keeping track of where control must go is done by means
1229        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1230        hide most of the details from the main code, and operates only if
1231        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1232        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1233        operating.
1234    
1235        To make it easier for callers to provide specially tailored get/free
1236        functions for this usage, two new functions, pcre_stack_malloc, and
1237        pcre_stack_free, are used. They are always called in strict stacking order,
1238        and the size of block requested is always the same.
1239    
1240        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1241        PCRE has been compiled to use the stack or the heap for recursion. The
1242        -C option of pcretest uses this to show which version is compiled.
1243    
1244        A new data escape \S, is added to pcretest; it causes the amounts of store
1245        obtained and freed by both kinds of malloc/free at match time to be added
1246        to the output.
1247    
1248     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1249        what's available on my current Linux desktop machine.
1250    
1251     3. When matching a UTF-8 string, the test for a valid string at the start has
1252        been extended. If start_offset is not zero, PCRE now checks that it points
1253        to a byte that is the start of a UTF-8 character. If not, it returns
1254        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1255        this is necessary because there may be backward assertions in the pattern.
1256        When matching the same subject several times, it may save resources to use
1257        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1258    
1259     4. The code for checking the validity of UTF-8 strings has been tightened so
1260        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1261        containing "overlong sequences".
1262    
1263     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1264        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1265        should have been "&", but it just so happened that all the cases this let
1266        through by mistake were picked up later in the function.
1267    
1268     6. I had used a variable called "isblank" - this is a C99 function, causing
1269        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1270    
1271     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1272        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1273        so the version is shown; (c) stop "make test" echoing "./RunTest".
1274    
1275     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1276    
1277     9. The prototype for memmove() for systems that don't have it was using
1278        size_t, but the inclusion of the header that defines size_t was later. I've
1279        moved the #includes for the C headers earlier to avoid this.
1280    
1281    10. Added some adjustments to the code to make it easier to compiler on certain
1282        special systems:
1283    
1284          (a) Some "const" qualifiers were missing.
1285          (b) Added the macro EXPORT before all exported functions; by default this
1286              is defined to be empty.
1287          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1288              that it reads its output file name as an argument instead of writing
1289              to the standard output and assuming this can be redirected.
1290    
1291    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1292        class containing characters with values greater than 255, PCRE compilation
1293        went into a loop.
1294    
1295    12. A recursive reference to a subpattern that was within another subpattern
1296        that had a minimum quantifier of zero caused PCRE to crash. For example,
1297        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1298        recursion. If the recursively-called subpattern itself had a zero repeat,
1299        that was OK.
1300    
1301    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1302        buffer into which it was copied (for escape processing) was still set at
1303        1024, so long lines caused crashes.
1304    
1305    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1306        "internal error: code overflow...". This applied to any character class
1307        that was followed by a possessive quantifier.
1308    
1309    15. Modified the Makefile to add libpcre.la as a prerequisite for
1310        libpcreposix.la because I was told this is needed for a parallel build to
1311        work.
1312    
1313    16. If a pattern that contained .* following optional items at the start was
1314        studied, the wrong optimizing data was generated, leading to matching
1315        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1316        matching string must start with a or b or c. The correct conclusion for
1317        this pattern is that a match can start with any character.
1318    
1319    
1320    Version 4.4 13-Aug-03
1321    ---------------------
1322    
1323     1. In UTF-8 mode, a character class containing characters with values between
1324        127 and 255 was not handled correctly if the compiled pattern was studied.
1325        In fixing this, I have also improved the studying algorithm for such
1326        classes (slightly).
1327    
1328     2. Three internal functions had redundant arguments passed to them. Removal
1329        might give a very teeny performance improvement.
1330    
1331     3. Documentation bug: the value of the capture_top field in a callout is *one
1332        more than* the number of the hightest numbered captured substring.
1333    
1334     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1335        in incorrectly linking with a previously installed version. They now link
1336        explicitly with libpcre.la.
1337    
1338     5. configure.in no longer needs to recognize Cygwin specially.
1339    
1340     6. A problem in pcre.in for Windows platforms is fixed.
1341    
1342     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1343        pcretest, it used to include the size of the study block as part of its
1344        output. Unfortunately, the structure contains a field that has a different
1345        size on different hardware architectures. This meant that the tests that
1346        showed this size failed. As the block is currently always of a fixed size,
1347        this information isn't actually particularly useful in pcretest output, so
1348        I have just removed it.
1349    
1350     8. Three pre-processor statements accidentally did not start in column 1.
1351        Sadly, there are *still* compilers around that complain, even though
1352        standard C has not required this for well over a decade. Sigh.
1353    
1354     9. In pcretest, the code for checking callouts passed small integers in the
1355        callout_data field, which is a void * field. However, some picky compilers
1356        complained about the casts involved for this on 64-bit systems. Now
1357        pcretest passes the address of the small integer instead, which should get
1358        rid of the warnings.
1359    
1360    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1361        both compile and run time, and gives an error if an invalid UTF-8 sequence
1362        is found. There is a option for disabling this check in cases where the
1363        string is known to be correct and/or the maximum performance is wanted.
1364    
1365    11. In response to a bug report, I changed one line in Makefile.in from
1366    
1367            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1368        to
1369            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1370    
1371        to look similar to other lines, but I have no way of telling whether this
1372        is the right thing to do, as I do not use Windows. No doubt I'll get told
1373        if it's wrong...
1374    
1375    
1376    Version 4.3 21-May-03
1377    ---------------------
1378    
1379    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1380       Makefile.
1381    
1382    2. Some refactoring to improve the quality of the code:
1383    
1384       (i)   The utf8_table... variables are now declared "const".
1385    
1386       (ii)  The code for \cx, which used the "case flipping" table to upper case
1387             lower case letters, now just substracts 32. This is ASCII-specific,
1388             but the whole concept of \cx is ASCII-specific, so it seems
1389             reasonable.
1390    
1391       (iii) PCRE was using its character types table to recognize decimal and
1392             hexadecimal digits in the pattern. This is silly, because it handles
1393             only 0-9, a-f, and A-F, but the character types table is locale-
1394             specific, which means strange things might happen. A private
1395             table is now used for this - though it costs 256 bytes, a table is
1396             much faster than multiple explicit tests. Of course, the standard
1397             character types table is still used for matching digits in subject
1398             strings against \d.
1399    
1400       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1401             ending in _t are). So I've renamed it as ESC_tee.
1402    
1403    3. The first argument for regexec() in the POSIX wrapper should have been
1404       defined as "const".
1405    
1406    4. Changed pcretest to use malloc() for its buffers so that they can be
1407       Electric Fenced for debugging.
1408    
1409    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1410       to read one or more bytes before the start of the subject string. Often this
1411       had no effect on PCRE's behaviour, but in some circumstances it could
1412       provoke a segmentation fault.
1413    
1414    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1415       to try to read one or more bytes before the start of the subject string.
1416    
1417    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1418       UTF-8 support could misbehave in various ways if the subject string
1419       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1420       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1421       back over UTF-8 characters.)
1422    
1423    
1424    Version 4.2 14-Apr-03
1425    ---------------------
1426    
1427    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1428    
1429    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1430         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1431         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1432         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1433         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1434           and BUILD_EXEEXT
1435         Note: automatic setting of the BUILD variables is not yet working
1436         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1437           compile-time but not at link-time
1438         [LINK]: use for linking executables only
1439         make different versions for Windows and non-Windows
1440         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1441           libraries
1442         [LINK_FOR_BUILD]: new variable
1443         [OBJEXT]: use throughout
1444         [EXEEXT]: use throughout
1445         <winshared>: new target
1446         <wininstall>: new target
1447         <dftables.o>: use native compiler
1448         <dftables>: use native linker
1449         <install>: handle Windows platform correctly
1450         <clean>: ditto
1451         <check>: ditto
1452         copy DLL to top builddir before testing
1453    
1454       As part of these changes, -no-undefined was removed again. This was reported
1455       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1456       in any case.
1457    
1458    3. Some tidies to get rid of compiler warnings:
1459    
1460       . In the match_data structure, match_limit was an unsigned long int, whereas
1461         match_call_count was an int. I've made them both unsigned long ints.
1462    
1463       . In pcretest the fact that a const uschar * doesn't automatically cast to
1464         a void * provoked a warning.
1465    
1466       . Turning on some more compiler warnings threw up some "shadow" variables
1467         and a few more missing casts.
1468    
1469    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1470       option, a class that contained a single character with a value between 128
1471       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1472    
1473    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1474       option, a class that contained several characters, but with at least one
1475       whose value was between 128 and 255 caused PCRE to crash.
1476    
1477    
1478    Version 4.1 12-Mar-03
1479    ---------------------
1480    
1481    1. Compiling with gcc -pedantic found a couple of places where casts were
1482    needed, and a string in dftables.c that was longer than standard compilers are
1483    required to support.
1484    
1485    2. Compiling with Sun's compiler found a few more places where the code could
1486    be tidied up in order to avoid warnings.
1487    
1488    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1489    first of these names is deprecated in the latest Autoconf in favour of the name
1490    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1491    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1492    analogy I have changed it to CFLAGS_FOR_BUILD.
1493    
1494    4. Added -no-undefined to the linking command in the Makefile, because this is
1495    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1496    linking step for the pcreposix library.
1497    
1498    5. PCRE was failing to diagnose the case of two named groups with the same
1499    name.
1500    
1501    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1502    literal character that is needed in the subject for a match, and scans along to
1503    ensure that it is present before embarking on the full matching process. This
1504    saves time in cases of nested unlimited repeats that are never going to match.
1505    Problem: the scan can take a lot of time if the subject is very long (e.g.
1506    megabytes), thus penalizing straightforward matches. It is now done only if the
1507    amount of subject to be scanned is less than 1000 bytes.
1508    
1509    7. A lesser problem with the same optimization is that it was recording the
1510    first character of an anchored pattern as "needed", thus provoking a search
1511    right along the subject, even when the first match of the pattern was going to
1512    fail. The "needed" character is now not set for anchored patterns, unless it
1513    follows something in the pattern that is of non-fixed length. Thus, it still
1514    fulfils its original purpose of finding quick non-matches in cases of nested
1515    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1516    
1517    
1518    Version 4.0 17-Feb-03
1519    ---------------------
1520    
1521    1. If a comment in an extended regex that started immediately after a meta-item
1522    extended to the end of string, PCRE compiled incorrect data. This could lead to
1523    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1524    
1525    2. Moved to autoconf 2.53 and libtool 1.4.2.
1526    
1527    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1528    the special perltest8 script is no longer needed - all the tests can be run
1529    from a single perltest script.
1530    
1531    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1532    by \s. It has now been removed in PCRE. This means it isn't recognized as
1533    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1534    class [:space:] *does* include VT, thereby creating a mess.
1535    
1536    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1537    space and tab.
1538    
1539    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1540    its new features into the main test script, reducing the number of scripts.
1541    
1542    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1543    were backward compatible, and made the (?i) apply to the whole pattern, as if
1544    /i were given. Now it behaves more logically, and applies the option setting
1545    only to what follows. PCRE has been changed to follow suit. However, if it
1546    finds options settings right at the start of the pattern, it extracts them into
1547    the global options, as before. Thus, they show up in the info data.
1548    
1549    8. Added support for the \Q...\E escape sequence. Characters in between are
1550    treated as literals. This is slightly different from Perl in that $ and @ are
1551    also handled as literals inside the quotes. In Perl, they will cause variable
1552    interpolation. Note the following examples:
1553    
1554        Pattern            PCRE matches      Perl matches
1555    
1556        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1557        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1558        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1559    
1560    For compatibility with Perl, \Q...\E sequences are recognized inside character
1561    classes as well as outside them.
1562    
1563    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1564    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1565    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1566    signed/unsigned warnings.
1567    
1568    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1569    option for pcretest, so I've replaced it by a simple function that does just
1570    that job.
1571    
1572    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1573    "pcregrep -".
1574    
1575    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1576    Java package. This provides some syntactic sugar for simple cases of what my
1577    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1578    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1579    item, you can use this simplified notation. Note that only makes sense with
1580    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1581    greediness, whatever the setting of the PCRE_UNGREEDY option.
1582    
1583    13. A change of greediness default within a pattern was not taking effect at
1584    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1585    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1586    was abstracted outside.
1587    
1588    14. PCRE now supports the \G assertion. It is true when the current matching
1589    position is at the start point of the match. This differs from \A when the
1590    starting offset is non-zero. Used with the /g option of pcretest (or similar
1591    code), it works in the same way as it does for Perl's /g option. If all
1592    alternatives of a regex begin with \G, the expression is anchored to the start
1593    match position, and the "anchored" flag is set in the compiled expression.
1594    
1595    15. Some bugs concerning the handling of certain option changes within patterns
1596    have been fixed. These applied to options other than (?ims). For example,
1597    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1598    been the other way round. Some of this was related to change 7 above.
1599    
1600    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1601    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1602    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1603    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1604    
1605    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1606    mode. Unlike ".", it always matches newline, whatever the setting of
1607    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1608    assertions. Perl allows it, but it doesn't (in general) work because it can't
1609    calculate the length of the lookbehind. At least, that's the case for Perl
1610    5.8.0 - I've been told they are going to document that it doesn't work in
1611    future.
1612    
1613    18. Added an error diagnosis for escapes that PCRE does not support: these are
1614    \L, \l, \N, \P, \p, \U, \u, and \X.
1615    
1616    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1617    reading past the end of the pattern in cases such as /[abcd/.
1618    
1619    20. PCRE was getting more memory than necessary for patterns with classes that
1620    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1621    
1622    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1623    compiling PCRE for use with Virtual Pascal.
1624    
1625    22. Small fix to the Makefile to make it work properly if the build is done
1626    outside the source tree.
1627    
1628    23. Added a new extension: a condition to go with recursion. If a conditional
1629    subpattern starts with (?(R) the "true" branch is used if recursion has
1630    happened, whereas the "false" branch is used only at the top level.
1631    
1632    24. When there was a very long string of literal characters (over 255 bytes
1633    without UTF support, over 250 bytes with UTF support), the computation of how
1634    much memory was required could be incorrect, leading to segfaults or other
1635    strange effects.
1636    
1637    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1638    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1639    there was a subsequent back reference to those brackets. This meant that, for
1640    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1641    possible to check for precisely this case. All we can do is abandon the
1642    optimization if .* occurs inside capturing brackets when there are any back
1643    references whatsoever. (See below for a better fix that came later.)
1644    
1645    26. The handling of the optimization for finding the first character of a
1646    non-anchored pattern, and for finding a character that is required later in the
1647    match were failing in some cases. This didn't break the matching; it just
1648    failed to optimize when it could. The way this is done has been re-implemented.
1649    
1650    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1651    
1652    28. Added a new feature that provides some of the functionality that Perl
1653    provides with (?{...}). The facility is termed a "callout". The way it is done
1654    in PCRE is for the caller to provide an optional function, by setting
1655    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1656    global variable. By default it is unset, which disables all calling out. To get
1657    the function called, the regex must include (?C) at appropriate points. This
1658    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1659    This provides a means of identifying different callout points. When PCRE
1660    reaches such a point in the regex, if pcre_callout has been set, the external
1661    function is called. It is provided with data in a structure called
1662    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1663    matching continues; if it returns a non-zero value, the match at the current
1664    point fails. However, backtracking will occur if possible. [This was changed
1665    later and other features added - see item 49 below.]
1666    
1667    29. pcretest is upgraded to test the callout functionality. It provides a
1668    callout function that displays information. By default, it shows the start of
1669    the match and the current position in the text. There are some new data escapes
1670    to vary what happens:
1671    
1672        \C+         in addition, show current contents of captured substrings
1673        \C-         do not supply a callout function
1674        \C!n        return 1 when callout number n is reached
1675        \C!n!m      return 1 when callout number n is reached for the mth time
1676    
1677    30. If pcregrep was called with the -l option and just a single file name, it
1678    output "<stdin>" if a match was found, instead of the file name.
1679    
1680    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1681    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1682    pcre_exec(). This saves a malloc/free per call. The default value of
1683    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1684    when configuring.
1685    
1686    32. The default maximum size of a compiled pattern is 64K. There have been a
1687    few cases of people hitting this limit. The code now uses macros to handle the
1688    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1689    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1690    configuring. Tests 2 and 5 work only with 2-byte links because they output
1691    debugging information about compiled patterns.
1692    
1693    33. Internal code re-arrangements:
1694    
1695    (a) Moved the debugging function for printing out a compiled regex into
1696        its own source file (printint.c) and used #include to pull it into
1697        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1698        separate copies.
1699    
1700    (b) Defined the list of op-code names for debugging as a macro in
1701        internal.h so that it is next to the definition of the opcodes.
1702    
1703    (c) Defined a table of op-code lengths for simpler skipping along compiled
1704        code. This is again a macro in internal.h so that it is next to the
1705        definition of the opcodes.
1706    
1707    34. Added support for recursive calls to individual subpatterns, along the
1708    lines of Robin Houston's patch (but implemented somewhat differently).
1709    
1710    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1711    allow it to read and process whole directories in Win32. This code was
1712    contributed by Lionel Fourquaux; it has not been tested by me.
1713    
1714    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1715    used to name a group. Names consist of alphanumerics and underscores, and must
1716    be unique. Back references use the syntax (?P=name) and recursive calls use
1717    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1718    numbers. The function pcre_fullinfo() can be used after compilation to extract
1719    a name/number map. There are three relevant calls:
1720    
1721      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1722      PCRE_INFO_NAMECOUNT            yields the number of entries
1723      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1724    
1725    The map is a vector of fixed-size entries. The size of each entry depends on
1726    the length of the longest name used. The first two bytes of each entry are the
1727    group number, most significant byte first. There follows the corresponding
1728    name, zero terminated. The names are in alphabetical order.
1729    
1730    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1731    case instead of 255. Making it the same both with and without UTF-8 support
1732    means that the same test output works with both.
1733    
1734    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1735    calling malloc() with a zero argument.
1736    
1737    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1738    optimization. I've improved things by keeping a bitmap of backreferences with
1739    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1740    fact referenced, the optimization can be applied. It is unlikely that a
1741    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1742    the match to follow \n) will appear inside brackets with a number greater than
1743    31, but if it does, any back reference > 31 suppresses the optimization.
1744    
1745    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1746    of disabling numbered capturing parentheses. Any opening parenthesis that is
1747    not followed by ? behaves as if it were followed by ?: but named parentheses
1748    can still be used for capturing (and they will acquire numbers in the usual
1749    way).
1750    
1751    41. Redesigned the return codes from the match() function into yes/no/error so
1752    that errors can be passed back from deep inside the nested calls. A malloc
1753    failure while inside a recursive subpattern call now causes the
1754    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1755    
1756    42. It is now possible to set a limit on the number of times the match()
1757    function is called in a call to pcre_exec(). This facility makes it possible to
1758    limit the amount of recursion and backtracking, though not in a directly
1759    obvious way, because the match() function is used in a number of different
1760    circumstances. The count starts from zero for each position in the subject
1761    string (for non-anchored patterns). The default limit is, for compatibility, a
1762    large number, namely 10 000 000. You can change this in two ways:
1763    
1764    (a) When configuring PCRE before making, you can use --with-match-limit=n
1765        to set a default value for the compiled library.
1766    
1767    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1768        a different value is set. See 45 below.
1769    
1770    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1771    
1772    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1773    of things that can be changed at compile time. The first argument specifies
1774    what is wanted and the second points to where the information is to be placed.
1775    The current list of available information is:
1776    
1777      PCRE_CONFIG_UTF8
1778    
1779    The output is an integer that is set to one if UTF-8 support is available;
1780    otherwise it is set to zero.
1781    
1782      PCRE_CONFIG_NEWLINE
1783    
1784    The output is an integer that it set to the value of the code that is used for
1785    newline. It is either LF (10) or CR (13).
1786    
1787      PCRE_CONFIG_LINK_SIZE
1788    
1789    The output is an integer that contains the number of bytes used for internal
1790    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1791    
1792      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1793    
1794    The output is an integer that contains the threshold above which the POSIX
1795    interface uses malloc() for output vectors. See item 31 above.
1796    
1797      PCRE_CONFIG_MATCH_LIMIT
1798    
1799    The output is an unsigned integer that contains the default limit of the number
1800    of match() calls in a pcre_exec() execution. See 42 above.
1801    
1802    44. pcretest has been upgraded by the addition of the -C option. This causes it
1803    to extract all the available output from the new pcre_config() function, and to
1804    output it. The program then exits immediately.
1805    
1806    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1807    order to support additional features. One way would have been to define
1808    pcre_exec2() (for example) with extra arguments, but this would not have been
1809    extensible, and would also have required all calls to the original function to
1810    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1811    is used for passing in "extra" data from pcre_study().
1812    
1813    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1814    contains the following fields:
1815    
1816      flags         a bitmap indicating which of the following fields are set
1817      study_data    opaque data from pcre_study()
1818      match_limit   a way of specifying a limit on match() calls for a specific
1819                      call to pcre_exec()
1820      callout_data  data for callouts (see 49 below)
1821    
1822    The flag bits are also defined in pcre.h, and are
1823    
1824      PCRE_EXTRA_STUDY_DATA
1825      PCRE_EXTRA_MATCH_LIMIT
1826      PCRE_EXTRA_CALLOUT_DATA
1827    
1828    The pcre_study() function now returns one of these new pcre_extra blocks, with
1829    the actual study data pointed to by the study_data field, and the
1830    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1831    before. That is, this change is entirely upwards-compatible and requires no
1832    change to existing code.
1833    
1834    If you want to pass in additional data to pcre_exec(), you can either place it
1835    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1836    block.
1837    
1838    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1839    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1840    times with different match limits, until it finds the minimum value needed for
1841    pcre_exec() to complete. The value is then output. This can be instructive; for
1842    most simple matches the number is quite small, but for pathological cases it
1843    gets very large very quickly.
1844    
1845    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1846    returns the size of the data block pointed to by the study_data field in a
1847    pcre_extra block, that is, the value that was passed as the argument to
1848    pcre_malloc() when PCRE was getting memory in which to place the information
1849    created by pcre_study(). The fourth argument should point to a size_t variable.
1850    pcretest has been extended so that this information is shown after a successful
1851    pcre_study() call when information about the compiled regex is being displayed.
1852    
1853    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1854    because what follows is always an absolute path. (Later: it turns out that this
1855    is more than cosmetic for MinGW, because it doesn't like empty path
1856    components.)
1857    
1858    49. Some changes have been made to the callout feature (see 28 above):
1859    
1860    (i)  A callout function now has three choices for what it returns:
1861    
1862           0  =>  success, carry on matching
1863         > 0  =>  failure at this point, but backtrack if possible
1864         < 0  =>  serious error, return this value from pcre_exec()
1865    
1866         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1867         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1868         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1869         use by callout functions. It will never be used by PCRE itself.
1870    
1871    (ii) The pcre_extra structure (see 45 above) has a void * field called
1872         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1873         pcre_callout_block structure has a field of the same name. The contents of
1874         the field passed in the pcre_extra structure are passed to the callout
1875         function in the corresponding field in the callout block. This makes it
1876         easier to use the same callout-containing regex from multiple threads. For
1877         testing, the pcretest program has a new data escape
1878    
1879           \C*n        pass the number n (may be negative) as callout_data
1880    
1881         If the callout function in pcretest receives a non-zero value as
1882         callout_data, it returns that value.
1883    
1884    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1885    there were some redundant $(CFLAGS) in commands that are now specified as
1886    $(LINK), which already includes $(CFLAGS).
1887    
1888    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1889    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1890    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1891    one-byte characters throughout. Note that case-insensitive matching applies
1892    only to characters whose values are less than 256. PCRE doesn't support the
1893    notion of cases for higher-valued characters.
1894    
1895    (i)   A character class whose characters are all within 0-255 is handled as
1896          a bit map, and the map is inverted for negative classes. Previously, a
1897          character > 255 always failed to match such a class; however it should
1898          match if the class was a negative one (e.g. [^ab]). This has been fixed.
1899    
1900    (ii)  A negated character class with a single character < 255 is coded as
1901          "not this character" (OP_NOT). This wasn't working properly when the test
1902          character was multibyte, either singly or repeated.
1903    
1904    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1905          mode, for example: \x{100}{2,3}.
1906    
1907    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1908          singly or repeated) now correctly test multibyte characters. However,
1909          PCRE doesn't recognize any characters with values greater than 255 as
1910          digits, spaces, or word characters. Such characters always match \D, \S,
1911          and \W, and never match \d, \s, or \w.
1912    
1913    (v)   Classes may now contain characters and character ranges with values
1914          greater than 255. For example: [ab\x{100}-\x{400}].
1915    
1916    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
1917          PCRE in UTF-8 mode.
1918    
1919    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1920    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1921    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1922    value.)
1923    
1924    53. The single man page has become too large. I have therefore split it up into
1925    a number of separate man pages. These also give rise to individual HTML pages;
1926    these are now put in a separate directory, and there is an index.html page that
1927    lists them all. Some hyperlinking between the pages has been installed.
1928    
1929    54. Added convenience functions for handling named capturing parentheses.
1930    
1931    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1932    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1933    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1934    are faulted.
1935    
1936    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1937    calling configure. These values are used when compiling the dftables.c program
1938    which is run to generate the source of the default character tables. They
1939    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1940    you will need to set these values.
1941    
1942    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1943    
1944    
1945    Version 3.9 02-Jan-02
1946    ---------------------
1947    
1948    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1949    
1950    2. If --disable-static was given, the building process failed when trying to
1951    build pcretest and pcregrep. (For some reason it was using libtool to compile
1952    them, which is not right, as they aren't part of the library.)
1953    
1954    
1955    Version 3.8 18-Dec-01
1956    ---------------------
1957    
1958    1. The experimental UTF-8 code was completely screwed up. It was packing the
1959    bytes in the wrong order. How dumb can you get?
1960    
1961    
1962    Version 3.7 29-Oct-01
1963    ---------------------
1964    
1965    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1966    This caused pcretest, when used on the test data, to segfault. Unfortunately,
1967    this didn't happen under Solaris 8, where I normally test things.
1968    
1969    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1970    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1971    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1972    this fix an hour or so after the initial 3.7 release.)
1973    
1974    
1975    Version 3.6 23-Oct-01
1976    ---------------------
1977    
1978    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1979    offsets passed as NULL with zero offset count.
1980    
1981    2. The config.guess and config.sub files had not been updated when I moved to
1982    the latest autoconf.
1983    
1984    
1985    Version 3.5 15-Aug-01
1986    ---------------------
1987    
1988    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1989    had been forgotten.
1990    
1991    2. By using declared but undefined structures, we can avoid using "void"
1992    definitions in pcre.h while keeping the internal definitions of the structures
1993    private.
1994    
1995    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1996    user point of view, this means that both static and shared libraries are built
1997    by default, but this can be individually controlled. More of the work of
1998    handling this static/shared cases is now inside libtool instead of PCRE's make
1999    file.
2000    
2001    4. The pcretest utility is now installed along with pcregrep because it is
2002    useful for users (to test regexs) and by doing this, it automatically gets
2003    relinked by libtool. The documentation has been turned into a man page, so
2004    there are now .1, .txt, and .html versions in /doc.
2005    
2006    5. Upgrades to pcregrep:
2007       (i)   Added long-form option names like gnu grep.
2008       (ii)  Added --help to list all options with an explanatory phrase.
2009       (iii) Added -r, --recursive to recurse into sub-directories.
2010       (iv)  Added -f, --file to read patterns from a file.
2011    
2012    6. pcre_exec() was referring to its "code" argument before testing that
2013    argument for NULL (and giving an error if it was NULL).
2014    
2015    7. Upgraded Makefile.in to allow for compiling in a different directory from
2016    the source directory.
2017    
2018    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2019    options bits, the pointer it was passed was to an int instead of to an unsigned
2020    long int. This mattered only on 64-bit systems.
2021    
2022    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2023    generated) instead of pcre.in, which it its source. Also made the same change
2024    in several of the .c files.
2025    
2026    10. A new release of gcc defines printf() as a macro, which broke pcretest
2027    because it had an ifdef in the middle of a string argument for printf(). Fixed
2028    by using separate calls to printf().
2029    
2030    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2031    script, to force use of CR or LF instead of \n in the source. On non-Unix
2032    systems, the value can be set in config.h.
2033    
2034    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2035    absolute limit. Changed the text of the error message to make this clear, and
2036    likewise updated the man page.
2037    
2038    13. The limit of 99 on the number of capturing subpatterns has been removed.
2039    The new limit is 65535, which I hope will not be a "real" limit.
2040    
2041    
2042    Version 3.4 22-Aug-00
2043    ---------------------
2044    
2045    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2046    
2047    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2048    
2049    
2050    Version 3.3 01-Aug-00
2051    ---------------------
2052    
2053    1. If an octal character was given, but the value was greater than \377, it
2054    was not getting masked to the least significant bits, as documented. This could
2055    lead to crashes in some systems.
2056    
2057    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2058    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2059    
2060    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2061    These just pass their arguments on to (pcre_free)(), but they are provided
2062    because some uses of PCRE bind it to non-C systems that can call its functions,
2063    but cannot call free() or pcre_free() directly.
2064    
2065    4. Add "make test" as a synonym for "make check". Corrected some comments in
2066    the Makefile.
2067    
2068    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2069    Makefile.
2070    
2071    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2072    command called pgrep for grepping around the active processes.
2073    
2074    7. Added the beginnings of support for UTF-8 character strings.
2075    
2076    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2077    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2078    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2079    out for the ar command.)
2080    
2081    
2082    Version 3.2 12-May-00
2083    ---------------------
2084    
2085    This is purely a bug fixing release.
2086    
2087    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2088    of ZA. This was just one example of several cases that could provoke this bug,
2089    which was introduced by change 9 of version 2.00. The code for breaking
2090    infinite loops after an iteration that matches an empty string was't working
2091    correctly.
2092    
2093    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2094    when matched against abbab (for example). After matching an empty string, it
2095    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2096    caused it to match further down the string than it should.
2097    
2098    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2099    was there because it doesn't seem to be needed, and it causes trouble on some
2100    systems, as it is not a Standard C header. It has been removed.
2101    
2102    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2103    were reported on the Macintosh. The changes were from
2104    
2105      while ((c = *(++ptr)) != 0 && c != '\n');
2106    to
2107      while ((c = *(++ptr)) != 0 && c != '\n') ;
2108    
2109    Totally extraordinary, but if that's what it takes...
2110    
2111    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2112    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2113    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2114    assumes the way PCRE uses memmove() (always moving upwards).
2115    
2116    6. PCRE is being used in one environment where strchr() is not available. There
2117    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2118    faster code anyway.
2119    
2120    
2121    Version 3.1 09-Feb-00
2122    ---------------------
2123    
2124    The only change in this release is the fixing of some bugs in Makefile.in for
2125    the "install" target:
2126    
2127    (1) It was failing to install pcreposix.h.
2128    
2129    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2130    
2131    
2132    Version 3.0 01-Feb-00
2133    ---------------------
2134    
2135    1. Add support for the /+ modifier to perltest (to output $` like it does in
2136    pcretest).
2137    
2138    2. Add support for the /g modifier to perltest.
2139    
2140    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2141    matches null strings.
2142    
2143    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2144    pattern. Perl treats empty patterns specially - it reuses the most recent
2145    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2146    effect.
2147    
2148    5. The POSIX interface was broken in that it was just handing over the POSIX
2149    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2150    required a bigger vector, with some working space on the end. This means that
2151    the POSIX wrapper now has to get and free some memory, and copy the results.
2152    
2153    6. Added some simple autoconf support, placing the test data and the
2154    documentation in separate directories, re-organizing some of the
2155    information files, and making it build pcre-config (a GNU standard). Also added
2156    libtool support for building PCRE as a shared library, which is now the
2157    default.
2158    
2159    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2160    09 are not valid octal constants. Single digits will be used for minor values
2161    less than 10.
2162    
2163    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2164    existing programs that set these in the POSIX interface can use PCRE without
2165    modification.
2166    
2167    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2168    return all that pcre_info() returns, plus additional data. The pcre_info()
2169    function is retained for compatibility, but is considered to be obsolete.
2170    
2171    10. Added experimental recursion feature (?R) to handle one common case that
2172    Perl 5.6 will be able to do with (?p{...}).
2173    
2174    11. Added support for POSIX character classes like [:alpha:], which Perl is
2175    adopting.
2176    
2177    
2178    Version 2.08 31-Aug-99
2179    ----------------------
2180    
2181    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2182    trying to match at the startoffset position, but instead was moving forward to
2183    the next newline as if a previous match had failed.
2184    
2185    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2186    and could get into a loop if a null string was matched other than at the start
2187    of the subject.
2188    
2189    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2190    be distinguished at compile time, and for completeness also added PCRE_DATE.
2191    
2192    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2193    in GnuWin32 environments.
2194    
2195    
2196    Version 2.07 29-Jul-99
2197    ----------------------
2198    
2199    1. The documentation is now supplied in plain text form and HTML as well as in
2200    the form of man page sources.
2201    
2202    2. C++ compilers don't like assigning (void *) values to other pointer types.
2203    In particular this affects malloc(). Although there is no problem in Standard
2204    C, I've put in casts to keep C++ compilers happy.
2205    
2206    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2207    should be (const char *).
2208    
2209    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2210    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2211    However, I haven't made this a standard facility. The documentation doesn't
2212    mention it, and the Makefile doesn't support it.
2213    
2214    5. The Makefile now contains an "install" target, with editable destinations at
2215    the top of the file. The pcretest program is not installed.
2216    
2217    6. pgrep -V now gives the PCRE version number and date.
2218    
2219    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2220    causing the entire string to be ignored, instead of just the last character.
2221    
2222    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2223    non-matching string, it can take a very, very long time, even for strings of
2224    quite modest length, because of the nested recursion. PCRE now does better in
2225    some of these cases. It does this by remembering the last required literal
2226    character in the pattern, and pre-searching the subject to ensure it is present
2227    before running the real match. In other words, it applies a heuristic to detect
2228    some types of certain failure quickly, and in the above example, if presented
2229    with a string that has no trailing " it gives "no match" very quickly.
2230    
2231    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2232    other alternatives are tried instead.
2233    
2234    
2235    Version 2.06 09-Jun-99
2236    ----------------------
2237    
2238    1. Change pcretest's output for amount of store used to show just the code
2239    space, because the remainder (the data block) varies in size between 32-bit and
2240    64-bit systems.
2241    
2242    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2243    start matching at. This allows lookbehinds to work when searching for multiple
2244    occurrences in a string.
2245    
2246    3. Added additional options to pcretest for testing multiple occurrences:
2247    
2248       /+   outputs the rest of the string that follows a match
2249       /g   loops for multiple occurrences, using the new startoffset argument
2250       /G   loops for multiple occurrences by passing an incremented pointer
2251    
2252    4. PCRE wasn't doing the "first character" optimization for patterns starting
2253    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2254    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2255    the letter 'x'. On long subject strings, this gives a significant speed-up.
2256    
2257    
2258    Version 2.05 21-Apr-99
2259    ----------------------
2260    
2261    1. Changed the type of magic_number from int to long int so that it works
2262    properly on 16-bit systems.
2263    
2264    2. Fixed a bug which caused patterns starting with .* not to work correctly
2265    when the subject string contained newline characters. PCRE was assuming
2266    anchoring for such patterns in all cases, which is not correct because .* will
2267    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2268    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2269    must be retried after every newline in the subject.
2270    
2271    
2272    Version 2.04 18-Feb-99
2273    ----------------------
2274    
2275    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2276    computation of the store needed to hold the pattern was incorrect (too large).
2277    If such patterns were nested a few deep, this could multiply and become a real
2278    problem.
2279    
2280    2. Added /M option to pcretest to show the memory requirement of a specific
2281    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2282    
2283    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2284    compiled in such a way that the backtracking after subsequent failure was
2285    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2286    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2287    
2288    
2289    Version 2.03 02-Feb-99
2290    ----------------------
2291    
2292    1. Fixed typo and small mistake in man page.
2293    
2294    2. Added 4th condition (GPL supersedes if conflict) and created separate
2295    LICENCE file containing the conditions.
2296    
2297    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2298    Perl, that is the internal \ allows the delimiter to be included in the
2299    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2300    the final delimiter, add \ to the end of the pattern (to test the error).
2301    
2302    4. Added the convenience functions for extracting substrings after a successful
2303    match. Updated pcretest to make it able to test these functions.
2304    
2305    
2306    Version 2.02 14-Jan-99
2307    ----------------------
2308    
2309    1. Initialized the working variables associated with each extraction so that
2310    their saving and restoring doesn't refer to uninitialized store.
2311    
2312    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2313    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2314    fix the problem.
2315    
2316    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2317    calls, and wasn't printing the correct value for compiling calls. Increased the
2318    default value of LOOPREPEAT, and the number of significant figures in the
2319    times.
2320    
2321    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2322    
2323    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2324    a building problem on Windows NT with a FAT file system.
2325    
2326    
2327  Version 2.01 21-Oct-98  Version 2.01 21-Oct-98
2328  ----------------------  ----------------------

Legend:
Removed from v.25  
changed lines
  Added in v.147

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12