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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.1 05-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 maintain/132html script that I use to
25        generate HTML has been updated to handle .nf/.fi and to complain if it
26        encounters .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, for the benefit
30        of those who have to compile without Autotools (compare pcre.h).
31    
32     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
33        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
34        makevp.bat for the current PCRE, using the additional files !compile.txt,
35        !linklib.txt, and pcregexp.pas.
36    
37     6. A Windows user reported a minor discrepancy with test 2, which turned out
38        to be caused by a trailing space on an input line that had got lost in his
39        copy. The trailing space was an accident, so I've just removed it.
40    
41     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
42        that is needed.
43    
44     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
45        as "const" (a) because they are and (b) because it helps the PHP
46        maintainers who have recently made a script to detect big data structures
47        in the php code that should be moved to the .rodata section. I remembered
48        to update Builducptable as well, so it won't revert if ucptable.h is ever
49        re-created.
50    
51     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
52        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
53        order to be able to cut out the UTF-8 tables in the latter when UTF-8
54        support is not required. This saves 1.5-2K of code, which is important in
55        some applications.
56    
57        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
58        so as not to refer to the tables, even though these functions will never be
59        called when UTF-8 support is disabled. Otherwise there are problems with a
60        shared library.
61    
62    10. The emulated memmove() function in pcre_internal.h (provided for those
63        environments that have neither memmove() nor bcopy()) was defining its
64        arguments as char * instead of void *.
65    
66    
67    Version 7.0 19-Dec-06
68    ---------------------
69    
70     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
71        moving to gcc 4.1.1.
72    
73     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
74        sys/time.h, which is documented as needed for this function. It doesn't
75        seem to matter on Linux, but it showed up on some releases of OS X.
76    
77     3. It seems that there are systems where bytes whose values are greater than
78        127 match isprint() in the "C" locale. The "C" locale should be the
79        default when a C program starts up. In most systems, only ASCII printing
80        characters match isprint(). This difference caused the output from pcretest
81        to vary, making some of the tests fail. I have changed pcretest so that:
82    
83        (a) When it is outputting text in the compiled version of a pattern, bytes
84            other than 32-126 are always shown as hex escapes.
85    
86        (b) When it is outputting text that is a matched part of a subject string,
87            it does the same, unless a different locale has been set for the match
88            (using the /L modifier). In this case, it uses isprint() to decide.
89    
90     4. Fixed a major bug that caused incorrect computation of the amount of memory
91        required for a compiled pattern when options that changed within the
92        pattern affected the logic of the preliminary scan that determines the
93        length. The relevant options are -x, and -i in UTF-8 mode. The result was
94        that the computed length was too small. The symptoms of this bug were
95        either the PCRE error "internal error: code overflow" from pcre_compile(),
96        or a glibc crash with a message such as "pcretest: free(): invalid next
97        size (fast)". Examples of patterns that provoked this bug (shown in
98        pcretest format) are:
99    
100          /(?-x: )/x
101          /(?x)(?-x: \s*#\s*)/
102          /((?i)[\x{c0}])/8
103          /(?i:[\x{c0}])/8
104    
105        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
106        is now done differently.
107    
108     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
109        wrapper classes; (b) implement a new function in the C++ scanner that is
110        more efficient than the old way of doing things because it avoids levels of
111        recursion in the regex matching; (c) add a paragraph to the documentation
112        for the FullMatch() function.
113    
114     6. The escape sequence \n was being treated as whatever was defined as
115        "newline". Not only was this contrary to the documentation, which states
116        that \n is character 10 (hex 0A), but it also went horribly wrong when
117        "newline" was defined as CRLF. This has been fixed.
118    
119     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
120        was being set to -1 for the "end of line" case (supposedly a value that no
121        character can have). Though this value is never used (the check for end of
122        line is "zero bytes in current character"), it caused compiler complaints.
123        I've changed it to 0xffffffff.
124    
125     8. In pcre_version.c, the version string was being built by a sequence of
126        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
127        string (as it is for production releases) called a macro with an empty
128        argument. The C standard says the result of this is undefined. The gcc
129        compiler treats it as an empty string (which was what was wanted) but it is
130        reported that Visual C gives an error. The source has been hacked around to
131        avoid this problem.
132    
133     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
134        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
135        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
136        of them did).
137    
138    10. Originally, pcretest opened its input and output without "b"; then I was
139        told that "b" was needed in some environments, so it was added for release
140        5.0 to both the input and output. (It makes no difference on Unix-like
141        systems.) Later I was told that it is wrong for the input on Windows. I've
142        now abstracted the modes into two macros, to make it easier to fiddle with
143        them, and removed "b" from the input mode under Windows.
144    
145    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
146    
147    12. Added -help and --help to pcretest as an official way of being reminded
148        of the options.
149    
150    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
151        and pcrecpp.cc because they annoy compilers at high warning levels.
152    
153    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
154    
155    15. Fixed an occurrence of == in configure.ac that should have been = (shell
156        scripts are not C programs :-) and which was not noticed because it works
157        on Linux.
158    
159    16. pcretest is supposed to handle any length of pattern and data line (as one
160        line or as a continued sequence of lines) by extending its input buffer if
161        necessary. This feature was broken for very long pattern lines, leading to
162        a string of junk being passed to pcre_compile() if the pattern was longer
163        than about 50K.
164    
165    17. I have done a major re-factoring of the way pcre_compile() computes the
166        amount of memory needed for a compiled pattern. Previously, there was code
167        that made a preliminary scan of the pattern in order to do this. That was
168        OK when PCRE was new, but as the facilities have expanded, it has become
169        harder and harder to keep it in step with the real compile phase, and there
170        have been a number of bugs (see for example, 4 above). I have now found a
171        cunning way of running the real compile function in a "fake" mode that
172        enables it to compute how much memory it would need, while actually only
173        ever using a few hundred bytes of working memory and without too many
174        tests of the mode. This should make future maintenance and development
175        easier. A side effect of this work is that the limit of 200 on the nesting
176        depth of parentheses has been removed (though this was never a serious
177        limitation, I suspect). However, there is a downside: pcre_compile() now
178        runs more slowly than before (30% or more, depending on the pattern). I
179        hope this isn't a big issue. There is no effect on runtime performance.
180    
181    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
182        newline (only possible for the last line of a file) and it was a
183        pattern that set a locale (followed by /Lsomething), pcretest crashed.
184    
185    19. Added additional timing features to pcretest. (1) The -tm option now times
186        matching only, not compiling. (2) Both -t and -tm can be followed, as a
187        separate command line item, by a number that specifies the number of
188        repeats to use when timing. The default is 50000; this gives better
189        precision, but takes uncomfortably long for very large patterns.
190    
191    20. Extended pcre_study() to be more clever in cases where a branch of a
192        subpattern has no definite first character. For example, (a*|b*)[cd] would
193        previously give no result from pcre_study(). Now it recognizes that the
194        first character must be a, b, c, or d.
195    
196    21. There was an incorrect error "recursive call could loop indefinitely" if
197        a subpattern (or the entire pattern) that was being tested for matching an
198        empty string contained only one non-empty item after a nested subpattern.
199        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
200        incorrectly, because the \d was being skipped in the check.
201    
202    22. The pcretest program now has a new pattern option /B and a command line
203        option -b, which is equivalent to adding /B to every pattern. This causes
204        it to show the compiled bytecode, without the additional information that
205        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
206        is the same as /B/I).
207    
208    23. A new optimization is now able automatically to treat some sequences such
209        as a*b as a*+b. More specifically, if something simple (such as a character
210        or a simple class like \d) has an unlimited quantifier, and is followed by
211        something that cannot possibly match the quantified thing, the quantifier
212        is automatically "possessified".
213    
214    24. A recursive reference to a subpattern whose number was greater than 39
215        went wrong under certain circumstances in UTF-8 mode. This bug could also
216        have affected the operation of pcre_study().
217    
218    25. Realized that a little bit of performance could be had by replacing
219        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
220    
221    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
222    
223    27. Possessive quantifiers such as a++ were previously implemented by turning
224        them into atomic groups such as ($>a+). Now they have their own opcodes,
225        which improves performance. This includes the automatically created ones
226        from 23 above.
227    
228    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
229        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
230        the first matched character to be a colon. This applied both to named and
231        numbered groups.
232    
233    29. The ucpinternal.h header file was missing its idempotency #ifdef.
234    
235    30. I was sent a "project" file called libpcre.a.dev which I understand makes
236        building PCRE on Windows easier, so I have included it in the distribution.
237    
238    31. There is now a check in pcretest against a ridiculously large number being
239        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
240        loop, the loop is abandoned.
241    
242    32. Forward references to subpatterns in conditions such as (?(2)...) where
243        subpattern 2 is defined later cause pcre_compile() to search forwards in
244        the pattern for the relevant set of parentheses. This search went wrong
245        when there were unescaped parentheses in a character class, parentheses
246        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
247    
248    33. "Subroutine" calls and backreferences were previously restricted to
249        referencing subpatterns earlier in the regex. This restriction has now
250        been removed.
251    
252    34. Added a number of extra features that are going to be in Perl 5.10. On the
253        whole, these are just syntactic alternatives for features that PCRE had
254        previously implemented using the Python syntax or my own invention. The
255        other formats are all retained for compatibility.
256    
257        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
258            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
259            also .NET compatible.
260    
261        (b) A recursion or subroutine call to a named group can now be defined as
262            (?&name) as well as (?P>name).
263    
264        (c) A backreference to a named group can now be defined as \k<name> or
265            \k'name' as well as (?P=name). The new forms, as well as being in Perl
266            5.10, are also .NET compatible.
267    
268        (d) A conditional reference to a named group can now use the syntax
269            (?(<name>) or (?('name') as well as (?(name).
270    
271        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
272            groups (named and numbered) that are never evaluated inline, but can be
273            called as "subroutines" from elsewhere. In effect, the DEFINE condition
274            is always false. There may be only one alternative in such a group.
275    
276        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
277            as the simple (?(R). The condition is true only if the most recent
278            recursion is that of the given number or name. It does not search out
279            through the entire recursion stack.
280    
281        (g) The escape \gN or \g{N} has been added, where N is a positive or
282            negative number, specifying an absolute or relative reference.
283    
284    35. Tidied to get rid of some further signed/unsigned compiler warnings and
285        some "unreachable code" warnings.
286    
287    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
288        things, this adds five new scripts.
289    
290    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
291        There were also incompatibilities regarding the handling of \Q..\E inside
292        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
293        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
294    
295    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
296        matches an empty string, and forcibly breaks the loop. There were bugs in
297        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
298        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
299        separate and independent bugs (that affected different cases) have been
300        fixed.
301    
302    39. Refactored the code to abolish the use of different opcodes for small
303        capturing bracket numbers. This is a tidy that I avoided doing when I
304        removed the limit on the number of capturing brackets for 3.5 back in 2001.
305        The new approach is not only tidier, it makes it possible to reduce the
306        memory needed to fix the previous bug (38).
307    
308    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
309        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
310        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
311        mode.
312    
313    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
314        report.
315    
316    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
317        copy construction and assignment in the C++ wrapper.
318    
319    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
320        couple of bugs that could have given wrong results in the "--newline=crlf"
321        case.
322    
323    44. Added a number of casts and did some reorganization of signed/unsigned int
324        variables following suggestions from Dair Grant. Also renamed the variable
325        "this" as "item" because it is a C++ keyword.
326    
327    45. Arranged for dftables to add
328    
329          #include "pcre_internal.h"
330    
331        to pcre_chartables.c because without it, gcc 4.x may remove the array
332        definition from the final binary if PCRE is built into a static library and
333        dead code stripping is activated.
334    
335    46. For an unanchored pattern, if a match attempt fails at the start of a
336        newline sequence, and the newline setting is CRLF or ANY, and the next two
337        characters are CRLF, advance by two characters instead of one.
338    
339    
340    Version 6.7 04-Jul-06
341    ---------------------
342    
343     1. In order to handle tests when input lines are enormously long, pcretest has
344        been re-factored so that it automatically extends its buffers when
345        necessary. The code is crude, but this _is_ just a test program. The
346        default size has been increased from 32K to 50K.
347    
348     2. The code in pcre_study() was using the value of the re argument before
349        testing it for NULL. (Of course, in any sensible call of the function, it
350        won't be NULL.)
351    
352     3. The memmove() emulation function in pcre_internal.h, which is used on
353        systems that lack both memmove() and bcopy() - that is, hardly ever -
354        was missing a "static" storage class specifier.
355    
356     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
357        containing an extended class (one that cannot be represented by a bitmap
358        because it contains high-valued characters or Unicode property items, e.g.
359        [\pZ]). Almost always one would set UTF-8 mode when processing such a
360        pattern, but PCRE should not loop if you do not (it no longer does).
361        [Detail: two cases were found: (a) a repeated subpattern containing an
362        extended class; (b) a recursive reference to a subpattern that followed a
363        previous extended class. It wasn't skipping over the extended class
364        correctly when UTF-8 mode was not set.]
365    
366     5. A negated single-character class was not being recognized as fixed-length
367        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
368        compile error "lookbehind assertion is not fixed length".
369    
370     6. The RunPerlTest auxiliary script was showing an unexpected difference
371        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
372        write a Perl script that can interpret lines of an input file either as
373        byte characters or as UTF-8, which is what "perltest" was being required to
374        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
375        can't do is switch easily at run time between having the "use utf8;" pragma
376        or not. In the end, I fudged it by using the RunPerlTest script to insert
377        "use utf8;" explicitly for the UTF-8 tests.
378    
379     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
380        the end of the subject string, contrary to the documentation and to what
381        Perl does. This was true of both matching functions. Now it matches only at
382        the start of the subject and immediately after *internal* newlines.
383    
384     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
385        a pointer to an int instead of a pointer to an unsigned long int. This
386        caused problems on 64-bit systems.
387    
388     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
389        instance of the 'standard' template library not being so standard".
390    
391    10. There was no check on the number of named subpatterns nor the maximum
392        length of a subpattern name. The product of these values is used to compute
393        the size of the memory block for a compiled pattern. By supplying a very
394        long subpattern name and a large number of named subpatterns, the size
395        computation could be caused to overflow. This is now prevented by limiting
396        the length of names to 32 characters, and the number of named subpatterns
397        to 10,000.
398    
399    11. Subpatterns that are repeated with specific counts have to be replicated in
400        the compiled pattern. The size of memory for this was computed from the
401        length of the subpattern and the repeat count. The latter is limited to
402        65535, but there was no limit on the former, meaning that integer overflow
403        could in principle occur. The compiled length of a repeated subpattern is
404        now limited to 30,000 bytes in order to prevent this.
405    
406    12. Added the optional facility to have named substrings with the same name.
407    
408    13. Added the ability to use a named substring as a condition, using the
409        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
410        are numbers (not recommended). Forward references are permitted.
411    
412    14. Added forward references in named backreferences (if you see what I mean).
413    
414    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
415        pattern could run off the end of the subject. For example, the pattern
416        "(?s)(.{1,5})"8 did this with the subject "ab".
417    
418    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
419        PCRE_CASELESS was set when matching characters that were quantified with ?
420        or *.
421    
422    17. A character class other than a single negated character that had a minimum
423        but no maximum quantifier - for example [ab]{6,} - was not handled
424        correctly by pce_dfa_exec(). It would match only one character.
425    
426    18. A valid (though odd) pattern that looked like a POSIX character
427        class but used an invalid character after [ (for example [[,abc,]]) caused
428        pcre_compile() to give the error "Failed: internal error: code overflow" or
429        in some cases to crash with a glibc free() error. This could even happen if
430        the pattern terminated after [[ but there just happened to be a sequence of
431        letters, a binary zero, and a closing ] in the memory that followed.
432    
433    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
434        over the years. Originally (before any Unicode support), just the bottom 8
435        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
436        output from "man perlunicode" includes this:
437    
438          The regular expression compiler produces polymorphic opcodes.  That
439          is, the pattern adapts to the data and automatically switches to
440          the Unicode character scheme when presented with Unicode data--or
441          instead uses a traditional byte scheme when presented with byte
442          data.
443    
444        Sadly, a wide octal escape does not cause a switch, and in a string with
445        no other multibyte characters, these octal escapes are treated as before.
446        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
447        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
448        Unicode string.
449    
450        I have not perpetrated such confusion in PCRE. Up till now, it took just
451        the bottom 8 bits, as in old Perl. I have now made octal escapes with
452        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
453        translate to the appropriate multibyte character.
454    
455    29. Applied some refactoring to reduce the number of warnings from Microsoft
456        and Borland compilers. This has included removing the fudge introduced
457        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
458        a warning about an unused variable.
459    
460    21. PCRE has not included VT (character 0x0b) in the set of whitespace
461        characters since release 4.0, because Perl (from release 5.004) does not.
462        [Or at least, is documented not to: some releases seem to be in conflict
463        with the documentation.] However, when a pattern was studied with
464        pcre_study() and all its branches started with \s, PCRE still included VT
465        as a possible starting character. Of course, this did no harm; it just
466        caused an unnecessary match attempt.
467    
468    22. Removed a now-redundant internal flag bit that recorded the fact that case
469        dependency changed within the pattern. This was once needed for "required
470        byte" processing, but is no longer used. This recovers a now-scarce options
471        bit. Also moved the least significant internal flag bit to the most-
472        significant bit of the word, which was not previously used (hangover from
473        the days when it was an int rather than a uint) to free up another bit for
474        the future.
475    
476    23. Added support for CRLF line endings as well as CR and LF. As well as the
477        default being selectable at build time, it can now be changed at runtime
478        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
479        specify that it is scanning data with non-default line endings.
480    
481    24. Changed the definition of CXXLINK to make it agree with the definition of
482        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
483    
484    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
485        recursions. This makes a big different to stack usage for some patterns.
486    
487    26. If a subpattern containing a named recursion or subroutine reference such
488        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
489        the space required for the compiled pattern went wrong and gave too small a
490        value. Depending on the environment, this could lead to "Failed: internal
491        error: code overflow at offset 49" or "glibc detected double free or
492        corruption" errors.
493    
494    27. Applied patches from Google (a) to support the new newline modes and (b) to
495        advance over multibyte UTF-8 characters in GlobalReplace.
496    
497    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
498        difference for some implementation of PCRE in some Windows version.
499    
500    29. Added some extra testing facilities to pcretest:
501    
502        \q<number>   in a data line sets the "match limit" value
503        \Q<number>   in a data line sets the "match recursion limt" value
504        -S <number>  sets the stack size, where <number> is in megabytes
505    
506        The -S option isn't available for Windows.
507    
508    
509    Version 6.6 06-Feb-06
510    ---------------------
511    
512     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
513        in pcreposix.h. I have copied the definition from pcre.h.
514    
515     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
516        because pcre.h is no longer a built file.
517    
518     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
519        not normally included in the compiled code.
520    
521    
522    Version 6.5 01-Feb-06
523    ---------------------
524    
525     1. When using the partial match feature with pcre_dfa_exec(), it was not
526        anchoring the second and subsequent partial matches at the new starting
527        point. This could lead to incorrect results. For example, with the pattern
528        /1234/, partially matching against "123" and then "a4" gave a match.
529    
530     2. Changes to pcregrep:
531    
532        (a) All non-match returns from pcre_exec() were being treated as failures
533            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
534            error message is output. Some extra information is given for the
535            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
536            probably the only errors that are likely to be caused by users (by
537            specifying a regex that has nested indefinite repeats, for instance).
538            If there are more than 20 of these errors, pcregrep is abandoned.
539    
540        (b) A binary zero was treated as data while matching, but terminated the
541            output line if it was written out. This has been fixed: binary zeroes
542            are now no different to any other data bytes.
543    
544        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
545            used to set a locale for matching. The --locale=xxxx long option has
546            been added (no short equivalent) to specify a locale explicitly on the
547            pcregrep command, overriding the environment variables.
548    
549        (d) When -B was used with -n, some line numbers in the output were one less
550            than they should have been.
551    
552        (e) Added the -o (--only-matching) option.
553    
554        (f) If -A or -C was used with -c (count only), some lines of context were
555            accidentally printed for the final match.
556    
557        (g) Added the -H (--with-filename) option.
558    
559        (h) The combination of options -rh failed to suppress file names for files
560            that were found from directory arguments.
561    
562        (i) Added the -D (--devices) and -d (--directories) options.
563    
564        (j) Added the -F (--fixed-strings) option.
565    
566        (k) Allow "-" to be used as a file name for -f as well as for a data file.
567    
568        (l) Added the --colo(u)r option.
569    
570        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
571            is not present by default.
572    
573     3. A nasty bug was discovered in the handling of recursive patterns, that is,
574        items such as (?R) or (?1), when the recursion could match a number of
575        alternatives. If it matched one of the alternatives, but subsequently,
576        outside the recursion, there was a failure, the code tried to back up into
577        the recursion. However, because of the way PCRE is implemented, this is not
578        possible, and the result was an incorrect result from the match.
579    
580        In order to prevent this happening, the specification of recursion has
581        been changed so that all such subpatterns are automatically treated as
582        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
583    
584     4. I had overlooked the fact that, in some locales, there are characters for
585        which isalpha() is true but neither isupper() nor islower() are true. In
586        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
587        and ordfeminine) are like this. This affected the treatment of \w and \W
588        when they appeared in character classes, but not when they appeared outside
589        a character class. The bit map for "word" characters is now created
590        separately from the results of isalnum() instead of just taking it from the
591        upper, lower, and digit maps. (Plus the underscore character, of course.)
592    
593     5. The above bug also affected the handling of POSIX character classes such as
594        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
595        permanent tables. Instead, the bit maps for such a class were previously
596        created as the appropriate unions of the upper, lower, and digit bitmaps.
597        Now they are created by subtraction from the [[:word:]] class, which has
598        its own bitmap.
599    
600     6. The [[:blank:]] character class matches horizontal, but not vertical space.
601        It is created by subtracting the vertical space characters (\x09, \x0a,
602        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
603        subtraction was done in the overall bitmap for a character class, meaning
604        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
605        be recognized. This bug has been fixed.
606    
607     7. Patches from the folks at Google:
608    
609          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
610          real life, but is still worth protecting against".
611    
612          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
613          regular expressions".
614    
615          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
616          have it.
617    
618          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
619          "configure" and the latter not, in order to fix a problem somebody had
620          with compiling the Arg class on HP-UX.
621    
622          (e) Improve the error-handling of the C++ wrapper a little bit.
623    
624          (f) New tests for checking recursion limiting.
625    
626     8. The pcre_memmove() function, which is used only if the environment does not
627        have a standard memmove() function (and is therefore rarely compiled),
628        contained two bugs: (a) use of int instead of size_t, and (b) it was not
629        returning a result (though PCRE never actually uses the result).
630    
631     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
632        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
633        returned instead of calling malloc() with an overflowing number that would
634        most likely cause subsequent chaos.
635    
636    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
637    
638    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
639        with this option is matched, the nmatch and pmatch options of regexec() are
640        ignored.
641    
642    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
643        provided in case anyone wants to the the POSIX interface with UTF-8
644        strings.
645    
646    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
647        C++ linking (needed for some HP-UX environments).
648    
649    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
650        (unused parameter) and in the pcre_printint() function (omitted "default"
651        switch label when the default is to do nothing).
652    
653    15. Added some code to make it possible, when PCRE is compiled as a C++
654        library, to replace subject pointers for pcre_exec() with a smart pointer
655        class, thus making it possible to process discontinuous strings.
656    
657    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
658        much the same function. They were added by different people who were trying
659        to make PCRE easy to compile on non-Unix systems. It has been suggested
660        that PCRE_EXPORT be abolished now that there is more automatic apparatus
661        for compiling on Windows systems. I have therefore replaced it with
662        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
663        defaults to "extern" for C or "extern C" for C++, which works fine on
664        Unix-like systems. It is now possible to override the value of PCRE_DATA_
665        SCOPE with something explicit in config.h. In addition:
666    
667        (a) pcreposix.h still had just "extern" instead of either of these macros;
668            I have replaced it with PCRE_DATA_SCOPE.
669    
670        (b) Functions such as _pcre_xclass(), which are internal to the library,
671            but external in the C sense, all had PCRE_EXPORT in their definitions.
672            This is apparently wrong for the Windows case, so I have removed it.
673            (It makes no difference on Unix-like systems.)
674    
675    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
676        of recursive calls to match(). This is different to MATCH_LIMIT because
677        that limits the total number of calls to match(), not all of which increase
678        the depth of recursion. Limiting the recursion depth limits the amount of
679        stack (or heap if NO_RECURSE is set) that is used. The default can be set
680        when PCRE is compiled, and changed at run time. A patch from Google adds
681        this functionality to the C++ interface.
682    
683    18. Changes to the handling of Unicode character properties:
684    
685        (a) Updated the table to Unicode 4.1.0.
686    
687        (b) Recognize characters that are not in the table as "Cn" (undefined).
688    
689        (c) I revised the way the table is implemented to a much improved format
690            which includes recognition of ranges. It now supports the ranges that
691            are defined in UnicodeData.txt, and it also amalgamates other
692            characters into ranges. This has reduced the number of entries in the
693            table from around 16,000 to around 3,000, thus reducing its size
694            considerably. I realized I did not need to use a tree structure after
695            all - a binary chop search is just as efficient. Having reduced the
696            number of entries, I extended their size from 6 bytes to 8 bytes to
697            allow for more data.
698    
699        (d) Added support for Unicode script names via properties such as \p{Han}.
700    
701    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
702        matching that character.
703    
704    20. When matching a repeated Unicode property with a minimum greater than zero,
705        (for example \pL{2,}), PCRE could look past the end of the subject if it
706        reached it while seeking the minimum number of characters. This could
707        happen only if some of the characters were more than one byte long, because
708        there is a check for at least the minimum number of bytes.
709    
710    21. Refactored the implementation of \p and \P so as to be more general, to
711        allow for more different types of property in future. This has changed the
712        compiled form incompatibly. Anybody with saved compiled patterns that use
713        \p or \P will have to recompile them.
714    
715    22. Added "Any" and "L&" to the supported property types.
716    
717    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
718        but give a compile time error if the value is greater than 0xff.
719    
720    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
721        accidentally not being installed or uninstalled.
722    
723    25. The pcre.h file was built from pcre.h.in, but the only changes that were
724        made were to insert the current release number. This seemed silly, because
725        it made things harder for people building PCRE on systems that don't run
726        "configure". I have turned pcre.h into a distributed file, no longer built
727        by "configure", with the version identification directly included. There is
728        no longer a pcre.h.in file.
729    
730        However, this change necessitated a change to the pcre-config script as
731        well. It is built from pcre-config.in, and one of the substitutions was the
732        release number. I have updated configure.ac so that ./configure now finds
733        the release number by grepping pcre.h.
734    
735    26. Added the ability to run the tests under valgrind.
736    
737    
738    Version 6.4 05-Sep-05
739    ---------------------
740    
741     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
742        "--" to be printed when multiple files were scanned, even when none of the
743        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
744        consider it to be a bug, and have restored the previous behaviour.
745    
746     2. A couple of code tidies to get rid of compiler warnings.
747    
748     3. The pcretest program used to cheat by referring to symbols in the library
749        whose names begin with _pcre_. These are internal symbols that are not
750        really supposed to be visible externally, and in some environments it is
751        possible to suppress them. The cheating is now confined to including
752        certain files from the library's source, which is a bit cleaner.
753    
754     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
755        file's purpose clearer.
756    
757     5. Reorganized pcre_ucp_findchar().
758    
759    
760    Version 6.3 15-Aug-05
761    ---------------------
762    
763     1. The file libpcre.pc.in did not have general read permission in the tarball.
764    
765     2. There were some problems when building without C++ support:
766    
767        (a) If C++ support was not built, "make install" and "make test" still
768            tried to test it.
769    
770        (b) There were problems when the value of CXX was explicitly set. Some
771            changes have been made to try to fix these, and ...
772    
773        (c) --disable-cpp can now be used to explicitly disable C++ support.
774    
775        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
776            backslash in a target when C++ was disabled. This confuses some
777            versions of "make", apparently. Using an intermediate variable solves
778            this. (Same for CPP_LOBJ.)
779    
780     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
781        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
782        necessary on certain architectures.
783    
784     4. Added a setting of -export-symbols-regex to the link command to remove
785        those symbols that are exported in the C sense, but actually are local
786        within the library, and not documented. Their names all begin with
787        "_pcre_". This is not a perfect job, because (a) we have to except some
788        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
789        available (and never for static libraries). I have made a note to try to
790        find a way round (a) in the future.
791    
792    
793  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
794  ---------------------  ---------------------
795    

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