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

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