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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 05-Jul-07
5    ---------------------
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
13          #include "pcre.h"
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
32     5. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp
33        unittest when running under MinGW.
35     6. ESC_K was left out of the EBCDIC table.
39    Version 7.2 19-Jun-07
40    ---------------------
42     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
43        which is apparently normally available under Windows.
45     2. Re-jig the pcregrep tests with different newline settings in an attempt
46        to make them independent of the local environment's newline setting.
48     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
50     4. Some of the "internals" tests were previously cut out when the link size
51        was not 2, because the output contained actual offsets. The recent new
52        "Z" feature of pcretest means that these can be cut out, making the tests
53        usable with all link sizes.
55     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
56        stack recursion. This gives a massive performance boost under BSD, but just
57        a small improvement under Linux. However, it saves one field in the frame
58        in all cases.
60     6. Added more features from the forthcoming Perl 5.10:
62        (a) (?-n) (where n is a string of digits) is a relative subroutine or
63            recursion call. It refers to the nth most recently opened parentheses.
65        (b) (?+n) is also a relative subroutine call; it refers to the nth next
66            to be opened parentheses.
68        (c) Conditions that refer to capturing parentheses can be specified
69            relatively, for example, (?(-2)... or (?(+3)...
71        (d) \K resets the start of the current match so that everything before
72            is not part of it.
74        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
76        (f) \g{name} is another synonym - part of Perl 5.10's unification of
77            reference syntax.
79        (g) (?| introduces a group in which the numbering of parentheses in each
80            alternative starts with the same number.
82        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
84     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
87     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
88        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
89        for detecting groups that can match an empty string.
91     9. A pattern with a very large number of alternatives (more than several
92        hundred) was running out of internal workspace during the pre-compile
93        phase, where pcre_compile() figures out how much memory will be needed. A
94        bit of new cunning has reduced the workspace needed for groups with
95        alternatives. The 1000-alternative test pattern now uses 12 bytes of
96        workspace instead of running out of the 4096 that are available.
98    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
100    11. Applied patch from Google to remove an optimization that didn't quite work.
101        The report of the bug said:
103          pcrecpp::RE("a*").FullMatch("aaa") matches, while
104          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
105          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
107    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
108        it matched the wrong number of bytes.
111    Version 7.1 24-Apr-07
112    ---------------------
114     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
115        that is more "standard", making use of automake and other Autotools. There
116        is some re-arrangement of the files and adjustment of comments consequent
117        on this.
119     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
120        for recursive directory scanning broke on some systems because the files
121        are not scanned in any specific order and on different systems the order
122        was different. A call to "sort" has been inserted into RunGrepTest for the
123        approprate test as a short-term fix. In the longer term there may be an
124        alternative.
126     3. I had an email from Eric Raymond about problems translating some of PCRE's
127        man pages to HTML (despite the fact that I distribute HTML pages, some
128        people do their own conversions for various reasons). The problems
129        concerned the use of low-level troff macros .br and .in. I have therefore
130        removed all such uses from the man pages (some were redundant, some could
131        be replaced by .nf/.fi pairs). The 132html script that I use to generate
132        HTML has been updated to handle .nf/.fi and to complain if it encounters
133        .br or .in.
135     4. Updated comments in configure.ac that get placed in config.h.in and also
136        arranged for config.h to be included in the distribution, with the name
137        config.h.generic, for the benefit of those who have to compile without
138        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
140     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
141        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
142        makevp.bat for the current PCRE, using the additional files
143        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
145     6. A Windows user reported a minor discrepancy with test 2, which turned out
146        to be caused by a trailing space on an input line that had got lost in his
147        copy. The trailing space was an accident, so I've just removed it.
149     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
150        that is needed.
152     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
153        as "const" (a) because they are and (b) because it helps the PHP
154        maintainers who have recently made a script to detect big data structures
155        in the php code that should be moved to the .rodata section. I remembered
156        to update Builducptable as well, so it won't revert if ucptable.h is ever
157        re-created.
159     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
160        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
161        order to be able to cut out the UTF-8 tables in the latter when UTF-8
162        support is not required. This saves 1.5-2K of code, which is important in
163        some applications.
165        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
166        so as not to refer to the tables, even though these functions will never be
167        called when UTF-8 support is disabled. Otherwise there are problems with a
168        shared library.
170    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
172        (a) It was defining its arguments as char * instead of void *.
174        (b) It was assuming that all moves were upwards in memory; this was true
175            a long time ago when I wrote it, but is no longer the case.
177        The emulated memove() is provided for those environments that have neither
178        memmove() nor bcopy(). I didn't think anyone used it these days, but that
179        is clearly not the case, as these two bugs were recently reported.
181    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
182        and Detrail to create the HTML documentation, the .txt form of the man
183        pages, and it removes trailing spaces from listed files. It also creates
184        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
185        case, it wraps all the #defines with #ifndefs. This script should be run
186        before "make dist".
188    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
189        with Unicode property support.
191        (a) For a maximizing quantifier, if the two different cases of the
192            character were of different lengths in their UTF-8 codings (there are
193            some cases like this - I found 11), and the matching function had to
194            back up over a mixture of the two cases, it incorrectly assumed they
195            were both the same length.
197        (b) When PCRE was configured to use the heap rather than the stack for
198            recursion during matching, it was not correctly preserving the data for
199            the other case of a UTF-8 character when checking ahead for a match
200            while processing a minimizing repeat. If the check also involved
201            matching a wide character, but failed, corruption could cause an
202            erroneous result when trying to check for a repeat of the original
203            character.
205    13. Some tidying changes to the testing mechanism:
207        (a) The RunTest script now detects the internal link size and whether there
208            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
209            values substituted by "configure". (The RunGrepTest script already did
210            this for UTF-8.) The configure.ac script no longer substitutes the
211            relevant variables.
213        (b) The debugging options /B and /D in pcretest show the compiled bytecode
214            with length and offset values. This means that the output is different
215            for different internal link sizes. Test 2 is skipped for link sizes
216            other than 2 because of this, bypassing the problem. Unfortunately,
217            there was also a test in test 3 (the locale tests) that used /B and
218            failed for link sizes other than 2. Rather than cut the whole test out,
219            I have added a new /Z option to pcretest that replaces the length and
220            offset values with spaces. This is now used to make test 3 independent
221            of link size. (Test 2 will be tidied up later.)
223    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
224        segmentation fault instead of returning the appropriate error message.
226    15. In multiline mode when the newline sequence was set to "any", the pattern
227        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
228        This doesn't seem right; it now treats the CRLF combination as the line
229        ending, and so does not match in that case. It's only a pattern such as ^$
230        that would hit this one: something like ^ABC$ would have failed after \r
231        and then tried again after \r\n.
233    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
234        in an attempt to make files that differ only in their line terminators
235        compare equal. This works on Linux.
237    17. Under certain error circumstances pcregrep might try to free random memory
238        as it exited. This is now fixed, thanks to valgrind.
240    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
241        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
242        was because its rules for how to advance for /g after matching an empty
243        string at the end of a line did not allow for this case. They now check for
244        it specially.
246    20. pcretest is supposed to handle patterns and data of any length, by
247        extending its buffers when necessary. It was getting this wrong when the
248        buffer for a data line had to be extended.
250    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
251        CRLF as a newline sequence.
253    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
254        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
255        I have nevertheless tidied it up.
257    23. Added some casts to kill warnings from HP-UX ia64 compiler.
259    24. Added a man page for pcre-config.
262    Version 7.0 19-Dec-06
263    ---------------------
265     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
266        moving to gcc 4.1.1.
268     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
269        sys/time.h, which is documented as needed for this function. It doesn't
270        seem to matter on Linux, but it showed up on some releases of OS X.
272     3. It seems that there are systems where bytes whose values are greater than
273        127 match isprint() in the "C" locale. The "C" locale should be the
274        default when a C program starts up. In most systems, only ASCII printing
275        characters match isprint(). This difference caused the output from pcretest
276        to vary, making some of the tests fail. I have changed pcretest so that:
278        (a) When it is outputting text in the compiled version of a pattern, bytes
279            other than 32-126 are always shown as hex escapes.
281        (b) When it is outputting text that is a matched part of a subject string,
282            it does the same, unless a different locale has been set for the match
283            (using the /L modifier). In this case, it uses isprint() to decide.
285     4. Fixed a major bug that caused incorrect computation of the amount of memory
286        required for a compiled pattern when options that changed within the
287        pattern affected the logic of the preliminary scan that determines the
288        length. The relevant options are -x, and -i in UTF-8 mode. The result was
289        that the computed length was too small. The symptoms of this bug were
290        either the PCRE error "internal error: code overflow" from pcre_compile(),
291        or a glibc crash with a message such as "pcretest: free(): invalid next
292        size (fast)". Examples of patterns that provoked this bug (shown in
293        pcretest format) are:
295          /(?-x: )/x
296          /(?x)(?-x: \s*#\s*)/
297          /((?i)[\x{c0}])/8
298          /(?i:[\x{c0}])/8
300        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
301        is now done differently.
303     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
304        wrapper classes; (b) implement a new function in the C++ scanner that is
305        more efficient than the old way of doing things because it avoids levels of
306        recursion in the regex matching; (c) add a paragraph to the documentation
307        for the FullMatch() function.
309     6. The escape sequence \n was being treated as whatever was defined as
310        "newline". Not only was this contrary to the documentation, which states
311        that \n is character 10 (hex 0A), but it also went horribly wrong when
312        "newline" was defined as CRLF. This has been fixed.
314     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
315        was being set to -1 for the "end of line" case (supposedly a value that no
316        character can have). Though this value is never used (the check for end of
317        line is "zero bytes in current character"), it caused compiler complaints.
318        I've changed it to 0xffffffff.
320     8. In pcre_version.c, the version string was being built by a sequence of
321        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
322        string (as it is for production releases) called a macro with an empty
323        argument. The C standard says the result of this is undefined. The gcc
324        compiler treats it as an empty string (which was what was wanted) but it is
325        reported that Visual C gives an error. The source has been hacked around to
326        avoid this problem.
328     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
329        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
330        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
331        of them did).
333    10. Originally, pcretest opened its input and output without "b"; then I was
334        told that "b" was needed in some environments, so it was added for release
335        5.0 to both the input and output. (It makes no difference on Unix-like
336        systems.) Later I was told that it is wrong for the input on Windows. I've
337        now abstracted the modes into two macros, to make it easier to fiddle with
338        them, and removed "b" from the input mode under Windows.
340    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
342    12. Added -help and --help to pcretest as an official way of being reminded
343        of the options.
345    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
346        and pcrecpp.cc because they annoy compilers at high warning levels.
348    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
350    15. Fixed an occurrence of == in configure.ac that should have been = (shell
351        scripts are not C programs :-) and which was not noticed because it works
352        on Linux.
354    16. pcretest is supposed to handle any length of pattern and data line (as one
355        line or as a continued sequence of lines) by extending its input buffer if
356        necessary. This feature was broken for very long pattern lines, leading to
357        a string of junk being passed to pcre_compile() if the pattern was longer
358        than about 50K.
360    17. I have done a major re-factoring of the way pcre_compile() computes the
361        amount of memory needed for a compiled pattern. Previously, there was code
362        that made a preliminary scan of the pattern in order to do this. That was
363        OK when PCRE was new, but as the facilities have expanded, it has become
364        harder and harder to keep it in step with the real compile phase, and there
365        have been a number of bugs (see for example, 4 above). I have now found a
366        cunning way of running the real compile function in a "fake" mode that
367        enables it to compute how much memory it would need, while actually only
368        ever using a few hundred bytes of working memory and without too many
369        tests of the mode. This should make future maintenance and development
370        easier. A side effect of this work is that the limit of 200 on the nesting
371        depth of parentheses has been removed (though this was never a serious
372        limitation, I suspect). However, there is a downside: pcre_compile() now
373        runs more slowly than before (30% or more, depending on the pattern). I
374        hope this isn't a big issue. There is no effect on runtime performance.
376    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
377        newline (only possible for the last line of a file) and it was a
378        pattern that set a locale (followed by /Lsomething), pcretest crashed.
380    19. Added additional timing features to pcretest. (1) The -tm option now times
381        matching only, not compiling. (2) Both -t and -tm can be followed, as a
382        separate command line item, by a number that specifies the number of
383        repeats to use when timing. The default is 50000; this gives better
384        precision, but takes uncomfortably long for very large patterns.
386    20. Extended pcre_study() to be more clever in cases where a branch of a
387        subpattern has no definite first character. For example, (a*|b*)[cd] would
388        previously give no result from pcre_study(). Now it recognizes that the
389        first character must be a, b, c, or d.
391    21. There was an incorrect error "recursive call could loop indefinitely" if
392        a subpattern (or the entire pattern) that was being tested for matching an
393        empty string contained only one non-empty item after a nested subpattern.
394        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
395        incorrectly, because the \d was being skipped in the check.
397    22. The pcretest program now has a new pattern option /B and a command line
398        option -b, which is equivalent to adding /B to every pattern. This causes
399        it to show the compiled bytecode, without the additional information that
400        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
401        is the same as /B/I).
403    23. A new optimization is now able automatically to treat some sequences such
404        as a*b as a*+b. More specifically, if something simple (such as a character
405        or a simple class like \d) has an unlimited quantifier, and is followed by
406        something that cannot possibly match the quantified thing, the quantifier
407        is automatically "possessified".
409    24. A recursive reference to a subpattern whose number was greater than 39
410        went wrong under certain circumstances in UTF-8 mode. This bug could also
411        have affected the operation of pcre_study().
413    25. Realized that a little bit of performance could be had by replacing
414        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
416    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
418    27. Possessive quantifiers such as a++ were previously implemented by turning
419        them into atomic groups such as ($>a+). Now they have their own opcodes,
420        which improves performance. This includes the automatically created ones
421        from 23 above.
423    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
424        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
425        the first matched character to be a colon. This applied both to named and
426        numbered groups.
428    29. The ucpinternal.h header file was missing its idempotency #ifdef.
430    30. I was sent a "project" file called libpcre.a.dev which I understand makes
431        building PCRE on Windows easier, so I have included it in the distribution.
433    31. There is now a check in pcretest against a ridiculously large number being
434        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
435        loop, the loop is abandoned.
437    32. Forward references to subpatterns in conditions such as (?(2)...) where
438        subpattern 2 is defined later cause pcre_compile() to search forwards in
439        the pattern for the relevant set of parentheses. This search went wrong
440        when there were unescaped parentheses in a character class, parentheses
441        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
443    33. "Subroutine" calls and backreferences were previously restricted to
444        referencing subpatterns earlier in the regex. This restriction has now
445        been removed.
447    34. Added a number of extra features that are going to be in Perl 5.10. On the
448        whole, these are just syntactic alternatives for features that PCRE had
449        previously implemented using the Python syntax or my own invention. The
450        other formats are all retained for compatibility.
452        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
453            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
454            also .NET compatible.
456        (b) A recursion or subroutine call to a named group can now be defined as
457            (?&name) as well as (?P>name).
459        (c) A backreference to a named group can now be defined as \k<name> or
460            \k'name' as well as (?P=name). The new forms, as well as being in Perl
461            5.10, are also .NET compatible.
463        (d) A conditional reference to a named group can now use the syntax
464            (?(<name>) or (?('name') as well as (?(name).
466        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
467            groups (named and numbered) that are never evaluated inline, but can be
468            called as "subroutines" from elsewhere. In effect, the DEFINE condition
469            is always false. There may be only one alternative in such a group.
471        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
472            as the simple (?(R). The condition is true only if the most recent
473            recursion is that of the given number or name. It does not search out
474            through the entire recursion stack.
476        (g) The escape \gN or \g{N} has been added, where N is a positive or
477            negative number, specifying an absolute or relative reference.
479    35. Tidied to get rid of some further signed/unsigned compiler warnings and
480        some "unreachable code" warnings.
482    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
483        things, this adds five new scripts.
485    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
486        There were also incompatibilities regarding the handling of \Q..\E inside
487        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
488        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
490    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
491        matches an empty string, and forcibly breaks the loop. There were bugs in
492        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
493        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
494        separate and independent bugs (that affected different cases) have been
495        fixed.
497    39. Refactored the code to abolish the use of different opcodes for small
498        capturing bracket numbers. This is a tidy that I avoided doing when I
499        removed the limit on the number of capturing brackets for 3.5 back in 2001.
500        The new approach is not only tidier, it makes it possible to reduce the
501        memory needed to fix the previous bug (38).
503    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
504        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
505        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
506        mode.
508    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
509        report.
511    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
512        copy construction and assignment in the C++ wrapper.
514    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
515        couple of bugs that could have given wrong results in the "--newline=crlf"
516        case.
518    44. Added a number of casts and did some reorganization of signed/unsigned int
519        variables following suggestions from Dair Grant. Also renamed the variable
520        "this" as "item" because it is a C++ keyword.
522    45. Arranged for dftables to add
524          #include "pcre_internal.h"
526        to pcre_chartables.c because without it, gcc 4.x may remove the array
527        definition from the final binary if PCRE is built into a static library and
528        dead code stripping is activated.
530    46. For an unanchored pattern, if a match attempt fails at the start of a
531        newline sequence, and the newline setting is CRLF or ANY, and the next two
532        characters are CRLF, advance by two characters instead of one.
535  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
536  ---------------------  ---------------------

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