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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.2 01-May-07
5    ---------------------
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8        which is apparently normally available under Windows.
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11        to make them independent of the local environment's newline setting.
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
15     4. Some of the "internals" tests were previously cut out when the link size
16        was not 2, because the output contained actual offsets. The recent new
17        "Z" feature of pcretest means that these can be cut out, making the tests
18        usable with all link sizes.
20     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21        stack recursion. This gives a massive performance boost under BSD, but just
22        a small improvement under Linux. However, it saves one field in the frame
23        in all cases.
25     6. Added more features from the forthcoming Perl 5.10:
27        (a) (?-n) (where n is a string of digits) is a relative subroutine or
28            recursion call. It refers to the nth most recently opened parentheses.
30        (b) (?+n) is also a relative subroutine call; it refers to the nth next
31            to be opened parentheses.
33        (c) Conditions that refer to capturing parentheses can be specified
34            relatively, for example, (?(-2)... or (?(+3)...
36        (d) \K resets the start of the current match so that everything before
37            is not part of it.
39     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
43    Version 7.1 24-Apr-07
44    ---------------------
46     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
47        that is more "standard", making use of automake and other Autotools. There
48        is some re-arrangement of the files and adjustment of comments consequent
49        on this.
51     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
52        for recursive directory scanning broke on some systems because the files
53        are not scanned in any specific order and on different systems the order
54        was different. A call to "sort" has been inserted into RunGrepTest for the
55        approprate test as a short-term fix. In the longer term there may be an
56        alternative.
58     3. I had an email from Eric Raymond about problems translating some of PCRE's
59        man pages to HTML (despite the fact that I distribute HTML pages, some
60        people do their own conversions for various reasons). The problems
61        concerned the use of low-level troff macros .br and .in. I have therefore
62        removed all such uses from the man pages (some were redundant, some could
63        be replaced by .nf/.fi pairs). The 132html script that I use to generate
64        HTML has been updated to handle .nf/.fi and to complain if it encounters
65        .br or .in.
67     4. Updated comments in configure.ac that get placed in config.h.in and also
68        arranged for config.h to be included in the distribution, with the name
69        config.h.generic, for the benefit of those who have to compile without
70        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
72     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
73        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
74        makevp.bat for the current PCRE, using the additional files
75        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
77     6. A Windows user reported a minor discrepancy with test 2, which turned out
78        to be caused by a trailing space on an input line that had got lost in his
79        copy. The trailing space was an accident, so I've just removed it.
81     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
82        that is needed.
84     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
85        as "const" (a) because they are and (b) because it helps the PHP
86        maintainers who have recently made a script to detect big data structures
87        in the php code that should be moved to the .rodata section. I remembered
88        to update Builducptable as well, so it won't revert if ucptable.h is ever
89        re-created.
91     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
92        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
93        order to be able to cut out the UTF-8 tables in the latter when UTF-8
94        support is not required. This saves 1.5-2K of code, which is important in
95        some applications.
97        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
98        so as not to refer to the tables, even though these functions will never be
99        called when UTF-8 support is disabled. Otherwise there are problems with a
100        shared library.
102    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
104        (a) It was defining its arguments as char * instead of void *.
106        (b) It was assuming that all moves were upwards in memory; this was true
107            a long time ago when I wrote it, but is no longer the case.
109        The emulated memove() is provided for those environments that have neither
110        memmove() nor bcopy(). I didn't think anyone used it these days, but that
111        is clearly not the case, as these two bugs were recently reported.
113    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
114        and Detrail to create the HTML documentation, the .txt form of the man
115        pages, and it removes trailing spaces from listed files. It also creates
116        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
117        case, it wraps all the #defines with #ifndefs. This script should be run
118        before "make dist".
120    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
121        with Unicode property support.
123        (a) For a maximizing quantifier, if the two different cases of the
124            character were of different lengths in their UTF-8 codings (there are
125            some cases like this - I found 11), and the matching function had to
126            back up over a mixture of the two cases, it incorrectly assumed they
127            were both the same length.
129        (b) When PCRE was configured to use the heap rather than the stack for
130            recursion during matching, it was not correctly preserving the data for
131            the other case of a UTF-8 character when checking ahead for a match
132            while processing a minimizing repeat. If the check also involved
133            matching a wide character, but failed, corruption could cause an
134            erroneous result when trying to check for a repeat of the original
135            character.
137    13. Some tidying changes to the testing mechanism:
139        (a) The RunTest script now detects the internal link size and whether there
140            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
141            values substituted by "configure". (The RunGrepTest script already did
142            this for UTF-8.) The configure.ac script no longer substitutes the
143            relevant variables.
145        (b) The debugging options /B and /D in pcretest show the compiled bytecode
146            with length and offset values. This means that the output is different
147            for different internal link sizes. Test 2 is skipped for link sizes
148            other than 2 because of this, bypassing the problem. Unfortunately,
149            there was also a test in test 3 (the locale tests) that used /B and
150            failed for link sizes other than 2. Rather than cut the whole test out,
151            I have added a new /Z option to pcretest that replaces the length and
152            offset values with spaces. This is now used to make test 3 independent
153            of link size. (Test 2 will be tidied up later.)
155    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
156        segmentation fault instead of returning the appropriate error message.
158    15. In multiline mode when the newline sequence was set to "any", the pattern
159        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
160        This doesn't seem right; it now treats the CRLF combination as the line
161        ending, and so does not match in that case. It's only a pattern such as ^$
162        that would hit this one: something like ^ABC$ would have failed after \r
163        and then tried again after \r\n.
165    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
166        in an attempt to make files that differ only in their line terminators
167        compare equal. This works on Linux.
169    17. Under certain error circumstances pcregrep might try to free random memory
170        as it exited. This is now fixed, thanks to valgrind.
172    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
173        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
174        was because its rules for how to advance for /g after matching an empty
175        string at the end of a line did not allow for this case. They now check for
176        it specially.
178    20. pcretest is supposed to handle patterns and data of any length, by
179        extending its buffers when necessary. It was getting this wrong when the
180        buffer for a data line had to be extended.
182    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
183        CRLF as a newline sequence.
185    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
186        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
187        I have nevertheless tidied it up.
189    23. Added some casts to kill warnings from HP-UX ia64 compiler.
191    24. Added a man page for pcre-config.
194    Version 7.0 19-Dec-06
195    ---------------------
197     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
198        moving to gcc 4.1.1.
200     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
201        sys/time.h, which is documented as needed for this function. It doesn't
202        seem to matter on Linux, but it showed up on some releases of OS X.
204     3. It seems that there are systems where bytes whose values are greater than
205        127 match isprint() in the "C" locale. The "C" locale should be the
206        default when a C program starts up. In most systems, only ASCII printing
207        characters match isprint(). This difference caused the output from pcretest
208        to vary, making some of the tests fail. I have changed pcretest so that:
210        (a) When it is outputting text in the compiled version of a pattern, bytes
211            other than 32-126 are always shown as hex escapes.
213        (b) When it is outputting text that is a matched part of a subject string,
214            it does the same, unless a different locale has been set for the match
215            (using the /L modifier). In this case, it uses isprint() to decide.
217     4. Fixed a major bug that caused incorrect computation of the amount of memory
218        required for a compiled pattern when options that changed within the
219        pattern affected the logic of the preliminary scan that determines the
220        length. The relevant options are -x, and -i in UTF-8 mode. The result was
221        that the computed length was too small. The symptoms of this bug were
222        either the PCRE error "internal error: code overflow" from pcre_compile(),
223        or a glibc crash with a message such as "pcretest: free(): invalid next
224        size (fast)". Examples of patterns that provoked this bug (shown in
225        pcretest format) are:
227          /(?-x: )/x
228          /(?x)(?-x: \s*#\s*)/
229          /((?i)[\x{c0}])/8
230          /(?i:[\x{c0}])/8
232        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
233        is now done differently.
235     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
236        wrapper classes; (b) implement a new function in the C++ scanner that is
237        more efficient than the old way of doing things because it avoids levels of
238        recursion in the regex matching; (c) add a paragraph to the documentation
239        for the FullMatch() function.
241     6. The escape sequence \n was being treated as whatever was defined as
242        "newline". Not only was this contrary to the documentation, which states
243        that \n is character 10 (hex 0A), but it also went horribly wrong when
244        "newline" was defined as CRLF. This has been fixed.
246     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
247        was being set to -1 for the "end of line" case (supposedly a value that no
248        character can have). Though this value is never used (the check for end of
249        line is "zero bytes in current character"), it caused compiler complaints.
250        I've changed it to 0xffffffff.
252     8. In pcre_version.c, the version string was being built by a sequence of
253        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
254        string (as it is for production releases) called a macro with an empty
255        argument. The C standard says the result of this is undefined. The gcc
256        compiler treats it as an empty string (which was what was wanted) but it is
257        reported that Visual C gives an error. The source has been hacked around to
258        avoid this problem.
260     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
261        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
262        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
263        of them did).
265    10. Originally, pcretest opened its input and output without "b"; then I was
266        told that "b" was needed in some environments, so it was added for release
267        5.0 to both the input and output. (It makes no difference on Unix-like
268        systems.) Later I was told that it is wrong for the input on Windows. I've
269        now abstracted the modes into two macros, to make it easier to fiddle with
270        them, and removed "b" from the input mode under Windows.
272    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
274    12. Added -help and --help to pcretest as an official way of being reminded
275        of the options.
277    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
278        and pcrecpp.cc because they annoy compilers at high warning levels.
280    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
282    15. Fixed an occurrence of == in configure.ac that should have been = (shell
283        scripts are not C programs :-) and which was not noticed because it works
284        on Linux.
286    16. pcretest is supposed to handle any length of pattern and data line (as one
287        line or as a continued sequence of lines) by extending its input buffer if
288        necessary. This feature was broken for very long pattern lines, leading to
289        a string of junk being passed to pcre_compile() if the pattern was longer
290        than about 50K.
292    17. I have done a major re-factoring of the way pcre_compile() computes the
293        amount of memory needed for a compiled pattern. Previously, there was code
294        that made a preliminary scan of the pattern in order to do this. That was
295        OK when PCRE was new, but as the facilities have expanded, it has become
296        harder and harder to keep it in step with the real compile phase, and there
297        have been a number of bugs (see for example, 4 above). I have now found a
298        cunning way of running the real compile function in a "fake" mode that
299        enables it to compute how much memory it would need, while actually only
300        ever using a few hundred bytes of working memory and without too many
301        tests of the mode. This should make future maintenance and development
302        easier. A side effect of this work is that the limit of 200 on the nesting
303        depth of parentheses has been removed (though this was never a serious
304        limitation, I suspect). However, there is a downside: pcre_compile() now
305        runs more slowly than before (30% or more, depending on the pattern). I
306        hope this isn't a big issue. There is no effect on runtime performance.
308    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
309        newline (only possible for the last line of a file) and it was a
310        pattern that set a locale (followed by /Lsomething), pcretest crashed.
312    19. Added additional timing features to pcretest. (1) The -tm option now times
313        matching only, not compiling. (2) Both -t and -tm can be followed, as a
314        separate command line item, by a number that specifies the number of
315        repeats to use when timing. The default is 50000; this gives better
316        precision, but takes uncomfortably long for very large patterns.
318    20. Extended pcre_study() to be more clever in cases where a branch of a
319        subpattern has no definite first character. For example, (a*|b*)[cd] would
320        previously give no result from pcre_study(). Now it recognizes that the
321        first character must be a, b, c, or d.
323    21. There was an incorrect error "recursive call could loop indefinitely" if
324        a subpattern (or the entire pattern) that was being tested for matching an
325        empty string contained only one non-empty item after a nested subpattern.
326        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
327        incorrectly, because the \d was being skipped in the check.
329    22. The pcretest program now has a new pattern option /B and a command line
330        option -b, which is equivalent to adding /B to every pattern. This causes
331        it to show the compiled bytecode, without the additional information that
332        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
333        is the same as /B/I).
335    23. A new optimization is now able automatically to treat some sequences such
336        as a*b as a*+b. More specifically, if something simple (such as a character
337        or a simple class like \d) has an unlimited quantifier, and is followed by
338        something that cannot possibly match the quantified thing, the quantifier
339        is automatically "possessified".
341    24. A recursive reference to a subpattern whose number was greater than 39
342        went wrong under certain circumstances in UTF-8 mode. This bug could also
343        have affected the operation of pcre_study().
345    25. Realized that a little bit of performance could be had by replacing
346        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
348    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
350    27. Possessive quantifiers such as a++ were previously implemented by turning
351        them into atomic groups such as ($>a+). Now they have their own opcodes,
352        which improves performance. This includes the automatically created ones
353        from 23 above.
355    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
356        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
357        the first matched character to be a colon. This applied both to named and
358        numbered groups.
360    29. The ucpinternal.h header file was missing its idempotency #ifdef.
362    30. I was sent a "project" file called libpcre.a.dev which I understand makes
363        building PCRE on Windows easier, so I have included it in the distribution.
365    31. There is now a check in pcretest against a ridiculously large number being
366        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
367        loop, the loop is abandoned.
369    32. Forward references to subpatterns in conditions such as (?(2)...) where
370        subpattern 2 is defined later cause pcre_compile() to search forwards in
371        the pattern for the relevant set of parentheses. This search went wrong
372        when there were unescaped parentheses in a character class, parentheses
373        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
375    33. "Subroutine" calls and backreferences were previously restricted to
376        referencing subpatterns earlier in the regex. This restriction has now
377        been removed.
379    34. Added a number of extra features that are going to be in Perl 5.10. On the
380        whole, these are just syntactic alternatives for features that PCRE had
381        previously implemented using the Python syntax or my own invention. The
382        other formats are all retained for compatibility.
384        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
385            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
386            also .NET compatible.
388        (b) A recursion or subroutine call to a named group can now be defined as
389            (?&name) as well as (?P>name).
391        (c) A backreference to a named group can now be defined as \k<name> or
392            \k'name' as well as (?P=name). The new forms, as well as being in Perl
393            5.10, are also .NET compatible.
395        (d) A conditional reference to a named group can now use the syntax
396            (?(<name>) or (?('name') as well as (?(name).
398        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
399            groups (named and numbered) that are never evaluated inline, but can be
400            called as "subroutines" from elsewhere. In effect, the DEFINE condition
401            is always false. There may be only one alternative in such a group.
403        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
404            as the simple (?(R). The condition is true only if the most recent
405            recursion is that of the given number or name. It does not search out
406            through the entire recursion stack.
408        (g) The escape \gN or \g{N} has been added, where N is a positive or
409            negative number, specifying an absolute or relative reference.
411    35. Tidied to get rid of some further signed/unsigned compiler warnings and
412        some "unreachable code" warnings.
414    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
415        things, this adds five new scripts.
417    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
418        There were also incompatibilities regarding the handling of \Q..\E inside
419        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
420        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
422    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
423        matches an empty string, and forcibly breaks the loop. There were bugs in
424        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
425        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
426        separate and independent bugs (that affected different cases) have been
427        fixed.
429    39. Refactored the code to abolish the use of different opcodes for small
430        capturing bracket numbers. This is a tidy that I avoided doing when I
431        removed the limit on the number of capturing brackets for 3.5 back in 2001.
432        The new approach is not only tidier, it makes it possible to reduce the
433        memory needed to fix the previous bug (38).
435    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
436        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
437        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
438        mode.
440    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
441        report.
443    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
444        copy construction and assignment in the C++ wrapper.
446    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
447        couple of bugs that could have given wrong results in the "--newline=crlf"
448        case.
450    44. Added a number of casts and did some reorganization of signed/unsigned int
451        variables following suggestions from Dair Grant. Also renamed the variable
452        "this" as "item" because it is a C++ keyword.
454    45. Arranged for dftables to add
456          #include "pcre_internal.h"
458        to pcre_chartables.c because without it, gcc 4.x may remove the array
459        definition from the final binary if PCRE is built into a static library and
460        dead code stripping is activated.
462    46. For an unanchored pattern, if a match attempt fails at the start of a
463        newline sequence, and the newline setting is CRLF or ANY, and the next two
464        characters are CRLF, advance by two characters instead of one.
467  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
468  ---------------------  ---------------------

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