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revision 67 by nigel, Sat Feb 24 21:40:13 2007 UTC revision 169 by ph10, Mon Jun 4 10:49:21 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.2 01-May-07
5    ---------------------
6    
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.
9    
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.
12    
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
14    
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.
19    
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.
24    
25     6. Added more features from the forthcoming Perl 5.10:
26    
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.
29    
30        (b) (?+n) is also a relative subroutine call; it refers to the nth next
31            to be opened parentheses.
32    
33        (c) Conditions that refer to capturing parentheses can be specified
34            relatively, for example, (?(-2)... or (?(+3)...
35    
36        (d) \K resets the start of the current match so that everything before
37            is not part of it.
38    
39     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
40        PCRE_INFO_JCHANGED.
41    
42    
43    Version 7.1 24-Apr-07
44    ---------------------
45    
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.
50    
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.
57    
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.
66    
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).
71    
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.
76    
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.
80    
81     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
82        that is needed.
83    
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.
90    
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.
96    
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.
101    
102    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
103    
104        (a) It was defining its arguments as char * instead of void *.
105    
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.
108    
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.
112    
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".
119    
120    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
121        with Unicode property support.
122    
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.
128    
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.
136    
137    13. Some tidying changes to the testing mechanism:
138    
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.
144    
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.)
154    
155    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
156        segmentation fault instead of returning the appropriate error message.
157    
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.
164    
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.
168    
169    17. Under certain error circumstances pcregrep might try to free random memory
170        as it exited. This is now fixed, thanks to valgrind.
171    
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.
177    
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.
181    
182    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
183        CRLF as a newline sequence.
184    
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.
188    
189    23. Added some casts to kill warnings from HP-UX ia64 compiler.
190    
191    24. Added a man page for pcre-config.
192    
193    
194    Version 7.0 19-Dec-06
195    ---------------------
196    
197     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
198        moving to gcc 4.1.1.
199    
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.
203    
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:
209    
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.
212    
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.
216    
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:
226    
227          /(?-x: )/x
228          /(?x)(?-x: \s*#\s*)/
229          /((?i)[\x{c0}])/8
230          /(?i:[\x{c0}])/8
231    
232        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
233        is now done differently.
234    
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.
240    
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.
245    
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.
251    
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.
259    
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).
264    
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.
271    
272    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
273    
274    12. Added -help and --help to pcretest as an official way of being reminded
275        of the options.
276    
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.
279    
280    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
281    
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.
285    
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.
291    
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.
307    
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.
311    
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.
317    
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.
322    
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.
328    
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).
334    
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".
340    
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().
344    
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.
347    
348    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
349    
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.
354    
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.
359    
360    29. The ucpinternal.h header file was missing its idempotency #ifdef.
361    
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.
364    
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.
368    
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.
374    
375    33. "Subroutine" calls and backreferences were previously restricted to
376        referencing subpatterns earlier in the regex. This restriction has now
377        been removed.
378    
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.
383    
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.
387    
388        (b) A recursion or subroutine call to a named group can now be defined as
389            (?&name) as well as (?P>name).
390    
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.
394    
395        (d) A conditional reference to a named group can now use the syntax
396            (?(<name>) or (?('name') as well as (?(name).
397    
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.
402    
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.
407    
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.
410    
411    35. Tidied to get rid of some further signed/unsigned compiler warnings and
412        some "unreachable code" warnings.
413    
414    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
415        things, this adds five new scripts.
416    
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.
421    
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.
428    
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).
434    
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.
439    
440    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
441        report.
442    
443    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
444        copy construction and assignment in the C++ wrapper.
445    
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.
449    
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.
453    
454    45. Arranged for dftables to add
455    
456          #include "pcre_internal.h"
457    
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.
461    
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.
465    
466    
467    Version 6.7 04-Jul-06
468    ---------------------
469    
470     1. In order to handle tests when input lines are enormously long, pcretest has
471        been re-factored so that it automatically extends its buffers when
472        necessary. The code is crude, but this _is_ just a test program. The
473        default size has been increased from 32K to 50K.
474    
475     2. The code in pcre_study() was using the value of the re argument before
476        testing it for NULL. (Of course, in any sensible call of the function, it
477        won't be NULL.)
478    
479     3. The memmove() emulation function in pcre_internal.h, which is used on
480        systems that lack both memmove() and bcopy() - that is, hardly ever -
481        was missing a "static" storage class specifier.
482    
483     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
484        containing an extended class (one that cannot be represented by a bitmap
485        because it contains high-valued characters or Unicode property items, e.g.
486        [\pZ]). Almost always one would set UTF-8 mode when processing such a
487        pattern, but PCRE should not loop if you do not (it no longer does).
488        [Detail: two cases were found: (a) a repeated subpattern containing an
489        extended class; (b) a recursive reference to a subpattern that followed a
490        previous extended class. It wasn't skipping over the extended class
491        correctly when UTF-8 mode was not set.]
492    
493     5. A negated single-character class was not being recognized as fixed-length
494        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
495        compile error "lookbehind assertion is not fixed length".
496    
497     6. The RunPerlTest auxiliary script was showing an unexpected difference
498        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
499        write a Perl script that can interpret lines of an input file either as
500        byte characters or as UTF-8, which is what "perltest" was being required to
501        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
502        can't do is switch easily at run time between having the "use utf8;" pragma
503        or not. In the end, I fudged it by using the RunPerlTest script to insert
504        "use utf8;" explicitly for the UTF-8 tests.
505    
506     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
507        the end of the subject string, contrary to the documentation and to what
508        Perl does. This was true of both matching functions. Now it matches only at
509        the start of the subject and immediately after *internal* newlines.
510    
511     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
512        a pointer to an int instead of a pointer to an unsigned long int. This
513        caused problems on 64-bit systems.
514    
515     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
516        instance of the 'standard' template library not being so standard".
517    
518    10. There was no check on the number of named subpatterns nor the maximum
519        length of a subpattern name. The product of these values is used to compute
520        the size of the memory block for a compiled pattern. By supplying a very
521        long subpattern name and a large number of named subpatterns, the size
522        computation could be caused to overflow. This is now prevented by limiting
523        the length of names to 32 characters, and the number of named subpatterns
524        to 10,000.
525    
526    11. Subpatterns that are repeated with specific counts have to be replicated in
527        the compiled pattern. The size of memory for this was computed from the
528        length of the subpattern and the repeat count. The latter is limited to
529        65535, but there was no limit on the former, meaning that integer overflow
530        could in principle occur. The compiled length of a repeated subpattern is
531        now limited to 30,000 bytes in order to prevent this.
532    
533    12. Added the optional facility to have named substrings with the same name.
534    
535    13. Added the ability to use a named substring as a condition, using the
536        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
537        are numbers (not recommended). Forward references are permitted.
538    
539    14. Added forward references in named backreferences (if you see what I mean).
540    
541    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
542        pattern could run off the end of the subject. For example, the pattern
543        "(?s)(.{1,5})"8 did this with the subject "ab".
544    
545    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
546        PCRE_CASELESS was set when matching characters that were quantified with ?
547        or *.
548    
549    17. A character class other than a single negated character that had a minimum
550        but no maximum quantifier - for example [ab]{6,} - was not handled
551        correctly by pce_dfa_exec(). It would match only one character.
552    
553    18. A valid (though odd) pattern that looked like a POSIX character
554        class but used an invalid character after [ (for example [[,abc,]]) caused
555        pcre_compile() to give the error "Failed: internal error: code overflow" or
556        in some cases to crash with a glibc free() error. This could even happen if
557        the pattern terminated after [[ but there just happened to be a sequence of
558        letters, a binary zero, and a closing ] in the memory that followed.
559    
560    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
561        over the years. Originally (before any Unicode support), just the bottom 8
562        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
563        output from "man perlunicode" includes this:
564    
565          The regular expression compiler produces polymorphic opcodes.  That
566          is, the pattern adapts to the data and automatically switches to
567          the Unicode character scheme when presented with Unicode data--or
568          instead uses a traditional byte scheme when presented with byte
569          data.
570    
571        Sadly, a wide octal escape does not cause a switch, and in a string with
572        no other multibyte characters, these octal escapes are treated as before.
573        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
574        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
575        Unicode string.
576    
577        I have not perpetrated such confusion in PCRE. Up till now, it took just
578        the bottom 8 bits, as in old Perl. I have now made octal escapes with
579        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
580        translate to the appropriate multibyte character.
581    
582    29. Applied some refactoring to reduce the number of warnings from Microsoft
583        and Borland compilers. This has included removing the fudge introduced
584        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
585        a warning about an unused variable.
586    
587    21. PCRE has not included VT (character 0x0b) in the set of whitespace
588        characters since release 4.0, because Perl (from release 5.004) does not.
589        [Or at least, is documented not to: some releases seem to be in conflict
590        with the documentation.] However, when a pattern was studied with
591        pcre_study() and all its branches started with \s, PCRE still included VT
592        as a possible starting character. Of course, this did no harm; it just
593        caused an unnecessary match attempt.
594    
595    22. Removed a now-redundant internal flag bit that recorded the fact that case
596        dependency changed within the pattern. This was once needed for "required
597        byte" processing, but is no longer used. This recovers a now-scarce options
598        bit. Also moved the least significant internal flag bit to the most-
599        significant bit of the word, which was not previously used (hangover from
600        the days when it was an int rather than a uint) to free up another bit for
601        the future.
602    
603    23. Added support for CRLF line endings as well as CR and LF. As well as the
604        default being selectable at build time, it can now be changed at runtime
605        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
606        specify that it is scanning data with non-default line endings.
607    
608    24. Changed the definition of CXXLINK to make it agree with the definition of
609        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
610    
611    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
612        recursions. This makes a big different to stack usage for some patterns.
613    
614    26. If a subpattern containing a named recursion or subroutine reference such
615        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
616        the space required for the compiled pattern went wrong and gave too small a
617        value. Depending on the environment, this could lead to "Failed: internal
618        error: code overflow at offset 49" or "glibc detected double free or
619        corruption" errors.
620    
621    27. Applied patches from Google (a) to support the new newline modes and (b) to
622        advance over multibyte UTF-8 characters in GlobalReplace.
623    
624    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
625        difference for some implementation of PCRE in some Windows version.
626    
627    29. Added some extra testing facilities to pcretest:
628    
629        \q<number>   in a data line sets the "match limit" value
630        \Q<number>   in a data line sets the "match recursion limt" value
631        -S <number>  sets the stack size, where <number> is in megabytes
632    
633        The -S option isn't available for Windows.
634    
635    
636    Version 6.6 06-Feb-06
637    ---------------------
638    
639     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
640        in pcreposix.h. I have copied the definition from pcre.h.
641    
642     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
643        because pcre.h is no longer a built file.
644    
645     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
646        not normally included in the compiled code.
647    
648    
649    Version 6.5 01-Feb-06
650    ---------------------
651    
652     1. When using the partial match feature with pcre_dfa_exec(), it was not
653        anchoring the second and subsequent partial matches at the new starting
654        point. This could lead to incorrect results. For example, with the pattern
655        /1234/, partially matching against "123" and then "a4" gave a match.
656    
657     2. Changes to pcregrep:
658    
659        (a) All non-match returns from pcre_exec() were being treated as failures
660            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
661            error message is output. Some extra information is given for the
662            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
663            probably the only errors that are likely to be caused by users (by
664            specifying a regex that has nested indefinite repeats, for instance).
665            If there are more than 20 of these errors, pcregrep is abandoned.
666    
667        (b) A binary zero was treated as data while matching, but terminated the
668            output line if it was written out. This has been fixed: binary zeroes
669            are now no different to any other data bytes.
670    
671        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
672            used to set a locale for matching. The --locale=xxxx long option has
673            been added (no short equivalent) to specify a locale explicitly on the
674            pcregrep command, overriding the environment variables.
675    
676        (d) When -B was used with -n, some line numbers in the output were one less
677            than they should have been.
678    
679        (e) Added the -o (--only-matching) option.
680    
681        (f) If -A or -C was used with -c (count only), some lines of context were
682            accidentally printed for the final match.
683    
684        (g) Added the -H (--with-filename) option.
685    
686        (h) The combination of options -rh failed to suppress file names for files
687            that were found from directory arguments.
688    
689        (i) Added the -D (--devices) and -d (--directories) options.
690    
691        (j) Added the -F (--fixed-strings) option.
692    
693        (k) Allow "-" to be used as a file name for -f as well as for a data file.
694    
695        (l) Added the --colo(u)r option.
696    
697        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
698            is not present by default.
699    
700     3. A nasty bug was discovered in the handling of recursive patterns, that is,
701        items such as (?R) or (?1), when the recursion could match a number of
702        alternatives. If it matched one of the alternatives, but subsequently,
703        outside the recursion, there was a failure, the code tried to back up into
704        the recursion. However, because of the way PCRE is implemented, this is not
705        possible, and the result was an incorrect result from the match.
706    
707        In order to prevent this happening, the specification of recursion has
708        been changed so that all such subpatterns are automatically treated as
709        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
710    
711     4. I had overlooked the fact that, in some locales, there are characters for
712        which isalpha() is true but neither isupper() nor islower() are true. In
713        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
714        and ordfeminine) are like this. This affected the treatment of \w and \W
715        when they appeared in character classes, but not when they appeared outside
716        a character class. The bit map for "word" characters is now created
717        separately from the results of isalnum() instead of just taking it from the
718        upper, lower, and digit maps. (Plus the underscore character, of course.)
719    
720     5. The above bug also affected the handling of POSIX character classes such as
721        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
722        permanent tables. Instead, the bit maps for such a class were previously
723        created as the appropriate unions of the upper, lower, and digit bitmaps.
724        Now they are created by subtraction from the [[:word:]] class, which has
725        its own bitmap.
726    
727     6. The [[:blank:]] character class matches horizontal, but not vertical space.
728        It is created by subtracting the vertical space characters (\x09, \x0a,
729        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
730        subtraction was done in the overall bitmap for a character class, meaning
731        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
732        be recognized. This bug has been fixed.
733    
734     7. Patches from the folks at Google:
735    
736          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
737          real life, but is still worth protecting against".
738    
739          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
740          regular expressions".
741    
742          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
743          have it.
744    
745          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
746          "configure" and the latter not, in order to fix a problem somebody had
747          with compiling the Arg class on HP-UX.
748    
749          (e) Improve the error-handling of the C++ wrapper a little bit.
750    
751          (f) New tests for checking recursion limiting.
752    
753     8. The pcre_memmove() function, which is used only if the environment does not
754        have a standard memmove() function (and is therefore rarely compiled),
755        contained two bugs: (a) use of int instead of size_t, and (b) it was not
756        returning a result (though PCRE never actually uses the result).
757    
758     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
759        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
760        returned instead of calling malloc() with an overflowing number that would
761        most likely cause subsequent chaos.
762    
763    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
764    
765    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
766        with this option is matched, the nmatch and pmatch options of regexec() are
767        ignored.
768    
769    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
770        provided in case anyone wants to the the POSIX interface with UTF-8
771        strings.
772    
773    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
774        C++ linking (needed for some HP-UX environments).
775    
776    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
777        (unused parameter) and in the pcre_printint() function (omitted "default"
778        switch label when the default is to do nothing).
779    
780    15. Added some code to make it possible, when PCRE is compiled as a C++
781        library, to replace subject pointers for pcre_exec() with a smart pointer
782        class, thus making it possible to process discontinuous strings.
783    
784    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
785        much the same function. They were added by different people who were trying
786        to make PCRE easy to compile on non-Unix systems. It has been suggested
787        that PCRE_EXPORT be abolished now that there is more automatic apparatus
788        for compiling on Windows systems. I have therefore replaced it with
789        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
790        defaults to "extern" for C or "extern C" for C++, which works fine on
791        Unix-like systems. It is now possible to override the value of PCRE_DATA_
792        SCOPE with something explicit in config.h. In addition:
793    
794        (a) pcreposix.h still had just "extern" instead of either of these macros;
795            I have replaced it with PCRE_DATA_SCOPE.
796    
797        (b) Functions such as _pcre_xclass(), which are internal to the library,
798            but external in the C sense, all had PCRE_EXPORT in their definitions.
799            This is apparently wrong for the Windows case, so I have removed it.
800            (It makes no difference on Unix-like systems.)
801    
802    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
803        of recursive calls to match(). This is different to MATCH_LIMIT because
804        that limits the total number of calls to match(), not all of which increase
805        the depth of recursion. Limiting the recursion depth limits the amount of
806        stack (or heap if NO_RECURSE is set) that is used. The default can be set
807        when PCRE is compiled, and changed at run time. A patch from Google adds
808        this functionality to the C++ interface.
809    
810    18. Changes to the handling of Unicode character properties:
811    
812        (a) Updated the table to Unicode 4.1.0.
813    
814        (b) Recognize characters that are not in the table as "Cn" (undefined).
815    
816        (c) I revised the way the table is implemented to a much improved format
817            which includes recognition of ranges. It now supports the ranges that
818            are defined in UnicodeData.txt, and it also amalgamates other
819            characters into ranges. This has reduced the number of entries in the
820            table from around 16,000 to around 3,000, thus reducing its size
821            considerably. I realized I did not need to use a tree structure after
822            all - a binary chop search is just as efficient. Having reduced the
823            number of entries, I extended their size from 6 bytes to 8 bytes to
824            allow for more data.
825    
826        (d) Added support for Unicode script names via properties such as \p{Han}.
827    
828    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
829        matching that character.
830    
831    20. When matching a repeated Unicode property with a minimum greater than zero,
832        (for example \pL{2,}), PCRE could look past the end of the subject if it
833        reached it while seeking the minimum number of characters. This could
834        happen only if some of the characters were more than one byte long, because
835        there is a check for at least the minimum number of bytes.
836    
837    21. Refactored the implementation of \p and \P so as to be more general, to
838        allow for more different types of property in future. This has changed the
839        compiled form incompatibly. Anybody with saved compiled patterns that use
840        \p or \P will have to recompile them.
841    
842    22. Added "Any" and "L&" to the supported property types.
843    
844    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
845        but give a compile time error if the value is greater than 0xff.
846    
847    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
848        accidentally not being installed or uninstalled.
849    
850    25. The pcre.h file was built from pcre.h.in, but the only changes that were
851        made were to insert the current release number. This seemed silly, because
852        it made things harder for people building PCRE on systems that don't run
853        "configure". I have turned pcre.h into a distributed file, no longer built
854        by "configure", with the version identification directly included. There is
855        no longer a pcre.h.in file.
856    
857        However, this change necessitated a change to the pcre-config script as
858        well. It is built from pcre-config.in, and one of the substitutions was the
859        release number. I have updated configure.ac so that ./configure now finds
860        the release number by grepping pcre.h.
861    
862    26. Added the ability to run the tests under valgrind.
863    
864    
865    Version 6.4 05-Sep-05
866    ---------------------
867    
868     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
869        "--" to be printed when multiple files were scanned, even when none of the
870        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
871        consider it to be a bug, and have restored the previous behaviour.
872    
873     2. A couple of code tidies to get rid of compiler warnings.
874    
875     3. The pcretest program used to cheat by referring to symbols in the library
876        whose names begin with _pcre_. These are internal symbols that are not
877        really supposed to be visible externally, and in some environments it is
878        possible to suppress them. The cheating is now confined to including
879        certain files from the library's source, which is a bit cleaner.
880    
881     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
882        file's purpose clearer.
883    
884     5. Reorganized pcre_ucp_findchar().
885    
886    
887    Version 6.3 15-Aug-05
888    ---------------------
889    
890     1. The file libpcre.pc.in did not have general read permission in the tarball.
891    
892     2. There were some problems when building without C++ support:
893    
894        (a) If C++ support was not built, "make install" and "make test" still
895            tried to test it.
896    
897        (b) There were problems when the value of CXX was explicitly set. Some
898            changes have been made to try to fix these, and ...
899    
900        (c) --disable-cpp can now be used to explicitly disable C++ support.
901    
902        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
903            backslash in a target when C++ was disabled. This confuses some
904            versions of "make", apparently. Using an intermediate variable solves
905            this. (Same for CPP_LOBJ.)
906    
907     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
908        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
909        necessary on certain architectures.
910    
911     4. Added a setting of -export-symbols-regex to the link command to remove
912        those symbols that are exported in the C sense, but actually are local
913        within the library, and not documented. Their names all begin with
914        "_pcre_". This is not a perfect job, because (a) we have to except some
915        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
916        available (and never for static libraries). I have made a note to try to
917        find a way round (a) in the future.
918    
919    
920    Version 6.2 01-Aug-05
921    ---------------------
922    
923     1. There was no test for integer overflow of quantifier values. A construction
924        such as {1111111111111111} would give undefined results. What is worse, if
925        a minimum quantifier for a parenthesized subpattern overflowed and became
926        negative, the calculation of the memory size went wrong. This could have
927        led to memory overwriting.
928    
929     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
930    
931     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
932        operating environments where this matters.
933    
934     4. Applied Giuseppe Maxia's patch to add additional features for controlling
935        PCRE options from within the C++ wrapper.
936    
937     5. Named capturing subpatterns were not being correctly counted when a pattern
938        was compiled. This caused two problems: (a) If there were more than 100
939        such subpatterns, the calculation of the memory needed for the whole
940        compiled pattern went wrong, leading to an overflow error. (b) Numerical
941        back references of the form \12, where the number was greater than 9, were
942        not recognized as back references, even though there were sufficient
943        previous subpatterns.
944    
945     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
946        versions of gcc, e.g. 2.95.4.
947    
948    
949    Version 6.1 21-Jun-05
950    ---------------------
951    
952     1. There was one reference to the variable "posix" in pcretest.c that was not
953        surrounded by "#if !defined NOPOSIX".
954    
955     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
956        the cross-check on the old pcre_info() function, for the benefit of the
957        cut-down version of PCRE that is currently imported into Exim.
958    
959     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
960        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
961        patterns that start (?i) but I don't think that matters. The use of (?i) is
962        just an example; this all applies to the other options as well.
963    
964     4. Since libtool seems to echo the compile commands it is issuing, the output
965        from "make" can be reduced a bit by putting "@" in front of each libtool
966        compile command.
967    
968     5. Patch from the folks at Google for configure.in to be a bit more thorough
969        in checking for a suitable C++ installation before trying to compile the
970        C++ stuff. This should fix a reported problem when a compiler was present,
971        but no suitable headers.
972    
973     6. The man pages all had just "PCRE" as their title. I have changed them to
974        be the relevant file name. I have also arranged that these names are
975        retained in the file doc/pcre.txt, which is a concatenation in text format
976        of all the man pages except the little individual ones for each function.
977    
978     7. The NON-UNIX-USE file had not been updated for the different set of source
979        files that come with release 6. I also added a few comments about the C++
980        wrapper.
981    
982    
983    Version 6.0 07-Jun-05
984    ---------------------
985    
986     1. Some minor internal re-organization to help with my DFA experiments.
987    
988     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
989        didn't matter for the library itself when fully configured, but did matter
990        when compiling without UCP support, or within Exim, where the ucp files are
991        not imported.
992    
993     3. Refactoring of the library code to split up the various functions into
994        different source modules. The addition of the new DFA matching code (see
995        below) to a single monolithic source would have made it really too
996        unwieldy, quite apart from causing all the code to be include in a
997        statically linked application, when only some functions are used. This is
998        relevant even without the DFA addition now that patterns can be compiled in
999        one application and matched in another.
1000    
1001        The downside of splitting up is that there have to be some external
1002        functions and data tables that are used internally in different modules of
1003        the library but which are not part of the API. These have all had their
1004        names changed to start with "_pcre_" so that they are unlikely to clash
1005        with other external names.
1006    
1007     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1008        a different (DFA) algorithm. Although it is slower than the original
1009        function, it does have some advantages for certain types of matching
1010        problem.
1011    
1012     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1013        including restarting after a partial match.
1014    
1015     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1016        defined when compiling for Windows was sent to me. I have put it into the
1017        code, though I have no means of testing or verifying it.
1018    
1019     7. Added the pcre_refcount() auxiliary function.
1020    
1021     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1022        match before or at the first newline in the subject string. In pcretest,
1023        the /f option on a pattern can be used to set this.
1024    
1025     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1026        would behave wrongly. This has been present in PCRE since release 4.0.
1027    
1028    10. A number of changes to the pcregrep command:
1029    
1030        (a) Refactored how -x works; insert ^(...)$ instead of setting
1031            PCRE_ANCHORED and checking the length, in preparation for adding
1032            something similar for -w.
1033    
1034        (b) Added the -w (match as a word) option.
1035    
1036        (c) Refactored the way lines are read and buffered so as to have more
1037            than one at a time available.
1038    
1039        (d) Implemented a pcregrep test script.
1040    
1041        (e) Added the -M (multiline match) option. This allows patterns to match
1042            over several lines of the subject. The buffering ensures that at least
1043            8K, or the rest of the document (whichever is the shorter) is available
1044            for matching (and similarly the previous 8K for lookbehind assertions).
1045    
1046        (f) Changed the --help output so that it now says
1047    
1048              -w, --word-regex(p)
1049    
1050            instead of two lines, one with "regex" and the other with "regexp"
1051            because that confused at least one person since the short forms are the
1052            same. (This required a bit of code, as the output is generated
1053            automatically from a table. It wasn't just a text change.)
1054    
1055        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1056            option but starts with a hyphen. Could be a pattern or a path name
1057            starting with a hyphen, for instance.
1058    
1059        (h) "-" can be given as a file name to represent stdin.
1060    
1061        (i) When file names are being printed, "(standard input)" is used for
1062            the standard input, for compatibility with GNU grep. Previously
1063            "<stdin>" was used.
1064    
1065        (j) The option --label=xxx can be used to supply a name to be used for
1066            stdin when file names are being printed. There is no short form.
1067    
1068        (k) Re-factored the options decoding logic because we are going to add
1069            two more options that take data. Such options can now be given in four
1070            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1071    
1072        (l) Added the -A, -B, and -C options for requesting that lines of context
1073            around matches be printed.
1074    
1075        (m) Added the -L option to print the names of files that do not contain
1076            any matching lines, that is, the complement of -l.
1077    
1078        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1079            continue to scan other files.
1080    
1081        (o) The -s option was incorrectly implemented. For compatibility with other
1082            greps, it now suppresses the error message for a non-existent or non-
1083            accessible file (but not the return code). There is a new option called
1084            -q that suppresses the output of matching lines, which was what -s was
1085            previously doing.
1086    
1087        (p) Added --include and --exclude options to specify files for inclusion
1088            and exclusion when recursing.
1089    
1090    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1091        Hopefully, it now does.
1092    
1093    12. Missing cast in pcre_study().
1094    
1095    13. Added an "uninstall" target to the makefile.
1096    
1097    14. Replaced "extern" in the function prototypes in Makefile.in with
1098        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1099        world, but is set differently for Windows.
1100    
1101    15. Added a second compiling function called pcre_compile2(). The only
1102        difference is that it has an extra argument, which is a pointer to an
1103        integer error code. When there is a compile-time failure, this is set
1104        non-zero, in addition to the error test pointer being set to point to an
1105        error message. The new argument may be NULL if no error number is required
1106        (but then you may as well call pcre_compile(), which is now just a
1107        wrapper). This facility is provided because some applications need a
1108        numeric error indication, but it has also enabled me to tidy up the way
1109        compile-time errors are handled in the POSIX wrapper.
1110    
1111    16. Added VPATH=.libs to the makefile; this should help when building with one
1112        prefix path and installing with another. (Or so I'm told by someone who
1113        knows more about this stuff than I do.)
1114    
1115    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1116        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1117        match everything, including newlines. This is not POSIX-compatible, but
1118        somebody wanted the feature. From pcretest it can be activated by using
1119        both the P and the s flags.
1120    
1121    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1122    
1123    19. libpcre.pc was being incorrectly installed as executable.
1124    
1125    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1126        it now also looks for '\r' so that it will work unmodified on Windows.
1127    
1128    21. Added Google's contributed C++ wrapper to the distribution.
1129    
1130    22. Added some untidy missing memory free() calls in pcretest, to keep
1131        Electric Fence happy when testing.
1132    
1133    
1134    
1135    Version 5.0 13-Sep-04
1136    ---------------------
1137    
1138     1. Internal change: literal characters are no longer packed up into items
1139        containing multiple characters in a single byte-string. Each character
1140        is now matched using a separate opcode. However, there may be more than one
1141        byte in the character in UTF-8 mode.
1142    
1143     2. The pcre_callout_block structure has two new fields: pattern_position and
1144        next_item_length. These contain the offset in the pattern to the next match
1145        item, and its length, respectively.
1146    
1147     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1148        insertion of callouts before each pattern item. Added the /C option to
1149        pcretest to make use of this.
1150    
1151     4. On the advice of a Windows user, the lines
1152    
1153          #if defined(_WIN32) || defined(WIN32)
1154          _setmode( _fileno( stdout ), 0x8000 );
1155          #endif  /* defined(_WIN32) || defined(WIN32) */
1156    
1157        have been added to the source of pcretest. This apparently does useful
1158        magic in relation to line terminators.
1159    
1160     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1161        for the benefit of those environments where the "b" makes a difference.
1162    
1163     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1164        to know about it. I have put a hack into configure.in that adds in code
1165        to set GCC=yes if CC=icc. This seems to end up at a point in the
1166        generated configure script that is early enough to affect the setting of
1167        compiler options, which is what is needed, but I have no means of testing
1168        whether it really works. (The user who reported this had patched the
1169        generated configure script, which of course I cannot do.)
1170    
1171        LATER: After change 22 below (new libtool files), the configure script
1172        seems to know about icc (and also ecc). Therefore, I have commented out
1173        this hack in configure.in.
1174    
1175     7. Added support for pkg-config (2 patches were sent in).
1176    
1177     8. Negated POSIX character classes that used a combination of internal tables
1178        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1179        [[:^ascii]]. Typically, they would match almost any characters. The other
1180        POSIX classes were not broken in this way.
1181    
1182     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1183        to find the match, as PCRE was deluded into thinking that the match had to
1184        start at the start point or following a newline. The same bug applied to
1185        patterns with negative forward assertions or any backward assertions
1186        preceding ".*" at the start, unless the pattern required a fixed first
1187        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1188    
1189    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1190        starting at the last subject character, bytes beyond the end of the subject
1191        string were read.
1192    
1193    11. Renamed the variable "class" as "classbits" to make life easier for C++
1194        users. (Previously there was a macro definition, but it apparently wasn't
1195        enough.)
1196    
1197    12. Added the new field "tables" to the extra data so that tables can be passed
1198        in at exec time, or the internal tables can be re-selected. This allows
1199        a compiled regex to be saved and re-used at a later time by a different
1200        program that might have everything at different addresses.
1201    
1202    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1203        -R library as well as a -L library.
1204    
1205    14. The debugging options of pcretest (-d on the command line or D on a
1206        pattern) showed incorrect output for anything following an extended class
1207        that contained multibyte characters and which was followed by a quantifier.
1208    
1209    15. Added optional support for general category Unicode character properties
1210        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1211        support. It adds about 90K to the size of the library. The meanings of the
1212        inbuilt class escapes such as \d and \s have NOT been changed.
1213    
1214    16. Updated pcredemo.c to include calls to free() to release the memory for the
1215        compiled pattern.
1216    
1217    17. The generated file chartables.c was being created in the source directory
1218        instead of in the building directory. This caused the build to fail if the
1219        source directory was different from the building directory, and was
1220        read-only.
1221    
1222    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1223        file. No doubt somebody will tell me if they don't make sense... Also added
1224        Dan Mooney's comments about building on OpenVMS.
1225    
1226    19. Added support for partial matching via the PCRE_PARTIAL option for
1227        pcre_exec() and the \P data escape in pcretest.
1228    
1229    20. Extended pcretest with 3 new pattern features:
1230    
1231        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1232              write the compiled pattern to the file whose name is "rest-of-line".
1233              This is a straight binary dump of the data, with the saved pointer to
1234              the character tables forced to be NULL. The study data, if any, is
1235              written too. After writing, pcretest reads a new pattern.
1236    
1237        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1238              compiled pattern from the given file. There must not be any
1239              occurrences of "<" in the file name (pretty unlikely); if there are,
1240              pcretest will instead treat the initial "<" as a pattern delimiter.
1241              After reading in the pattern, pcretest goes on to read data lines as
1242              usual.
1243    
1244        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1245              and 16-bit fields in a compiled pattern, to simulate a pattern that
1246              was compiled on a host of opposite endianness.
1247    
1248    21. The pcre-exec() function can now cope with patterns that were compiled on
1249        hosts of opposite endianness, with this restriction:
1250    
1251          As for any compiled expression that is saved and used later, the tables
1252          pointer field cannot be preserved; the extra_data field in the arguments
1253          to pcre_exec() should be used to pass in a tables address if a value
1254          other than the default internal tables were used at compile time.
1255    
1256    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1257        now diagnosed as an error. Previously, most of the time, a negative number
1258        would have been treated as zero, but if in addition "ovector" was passed as
1259        NULL, a crash could occur.
1260    
1261    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1262        new versions from the libtool 1.5 distribution (the last one is a copy of
1263        a file called libtool.m4). This seems to have fixed the need to patch
1264        "configure" to support Darwin 1.3 (which I used to do). However, I still
1265        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1266        workstation).
1267    
1268    24. Changed the PCRE licence to be the more standard "BSD" licence.
1269    
1270    
1271    Version 4.5 01-Dec-03
1272    ---------------------
1273    
1274     1. There has been some re-arrangement of the code for the match() function so
1275        that it can be compiled in a version that does not call itself recursively.
1276        Instead, it keeps those local variables that need separate instances for
1277        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1278        needs to "recurse". Keeping track of where control must go is done by means
1279        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1280        hide most of the details from the main code, and operates only if
1281        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1282        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1283        operating.
1284    
1285        To make it easier for callers to provide specially tailored get/free
1286        functions for this usage, two new functions, pcre_stack_malloc, and
1287        pcre_stack_free, are used. They are always called in strict stacking order,
1288        and the size of block requested is always the same.
1289    
1290        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1291        PCRE has been compiled to use the stack or the heap for recursion. The
1292        -C option of pcretest uses this to show which version is compiled.
1293    
1294        A new data escape \S, is added to pcretest; it causes the amounts of store
1295        obtained and freed by both kinds of malloc/free at match time to be added
1296        to the output.
1297    
1298     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1299        what's available on my current Linux desktop machine.
1300    
1301     3. When matching a UTF-8 string, the test for a valid string at the start has
1302        been extended. If start_offset is not zero, PCRE now checks that it points
1303        to a byte that is the start of a UTF-8 character. If not, it returns
1304        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1305        this is necessary because there may be backward assertions in the pattern.
1306        When matching the same subject several times, it may save resources to use
1307        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1308    
1309     4. The code for checking the validity of UTF-8 strings has been tightened so
1310        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1311        containing "overlong sequences".
1312    
1313     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1314        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1315        should have been "&", but it just so happened that all the cases this let
1316        through by mistake were picked up later in the function.
1317    
1318     6. I had used a variable called "isblank" - this is a C99 function, causing
1319        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1320    
1321     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1322        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1323        so the version is shown; (c) stop "make test" echoing "./RunTest".
1324    
1325     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1326    
1327     9. The prototype for memmove() for systems that don't have it was using
1328        size_t, but the inclusion of the header that defines size_t was later. I've
1329        moved the #includes for the C headers earlier to avoid this.
1330    
1331    10. Added some adjustments to the code to make it easier to compiler on certain
1332        special systems:
1333    
1334          (a) Some "const" qualifiers were missing.
1335          (b) Added the macro EXPORT before all exported functions; by default this
1336              is defined to be empty.
1337          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1338              that it reads its output file name as an argument instead of writing
1339              to the standard output and assuming this can be redirected.
1340    
1341    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1342        class containing characters with values greater than 255, PCRE compilation
1343        went into a loop.
1344    
1345    12. A recursive reference to a subpattern that was within another subpattern
1346        that had a minimum quantifier of zero caused PCRE to crash. For example,
1347        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1348        recursion. If the recursively-called subpattern itself had a zero repeat,
1349        that was OK.
1350    
1351    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1352        buffer into which it was copied (for escape processing) was still set at
1353        1024, so long lines caused crashes.
1354    
1355    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1356        "internal error: code overflow...". This applied to any character class
1357        that was followed by a possessive quantifier.
1358    
1359    15. Modified the Makefile to add libpcre.la as a prerequisite for
1360        libpcreposix.la because I was told this is needed for a parallel build to
1361        work.
1362    
1363    16. If a pattern that contained .* following optional items at the start was
1364        studied, the wrong optimizing data was generated, leading to matching
1365        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1366        matching string must start with a or b or c. The correct conclusion for
1367        this pattern is that a match can start with any character.
1368    
1369    
1370    Version 4.4 13-Aug-03
1371    ---------------------
1372    
1373     1. In UTF-8 mode, a character class containing characters with values between
1374        127 and 255 was not handled correctly if the compiled pattern was studied.
1375        In fixing this, I have also improved the studying algorithm for such
1376        classes (slightly).
1377    
1378     2. Three internal functions had redundant arguments passed to them. Removal
1379        might give a very teeny performance improvement.
1380    
1381     3. Documentation bug: the value of the capture_top field in a callout is *one
1382        more than* the number of the hightest numbered captured substring.
1383    
1384     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1385        in incorrectly linking with a previously installed version. They now link
1386        explicitly with libpcre.la.
1387    
1388     5. configure.in no longer needs to recognize Cygwin specially.
1389    
1390     6. A problem in pcre.in for Windows platforms is fixed.
1391    
1392     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1393        pcretest, it used to include the size of the study block as part of its
1394        output. Unfortunately, the structure contains a field that has a different
1395        size on different hardware architectures. This meant that the tests that
1396        showed this size failed. As the block is currently always of a fixed size,
1397        this information isn't actually particularly useful in pcretest output, so
1398        I have just removed it.
1399    
1400     8. Three pre-processor statements accidentally did not start in column 1.
1401        Sadly, there are *still* compilers around that complain, even though
1402        standard C has not required this for well over a decade. Sigh.
1403    
1404     9. In pcretest, the code for checking callouts passed small integers in the
1405        callout_data field, which is a void * field. However, some picky compilers
1406        complained about the casts involved for this on 64-bit systems. Now
1407        pcretest passes the address of the small integer instead, which should get
1408        rid of the warnings.
1409    
1410    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1411        both compile and run time, and gives an error if an invalid UTF-8 sequence
1412        is found. There is a option for disabling this check in cases where the
1413        string is known to be correct and/or the maximum performance is wanted.
1414    
1415    11. In response to a bug report, I changed one line in Makefile.in from
1416    
1417            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1418        to
1419            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1420    
1421        to look similar to other lines, but I have no way of telling whether this
1422        is the right thing to do, as I do not use Windows. No doubt I'll get told
1423        if it's wrong...
1424    
1425    
1426    Version 4.3 21-May-03
1427    ---------------------
1428    
1429    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1430       Makefile.
1431    
1432    2. Some refactoring to improve the quality of the code:
1433    
1434       (i)   The utf8_table... variables are now declared "const".
1435    
1436       (ii)  The code for \cx, which used the "case flipping" table to upper case
1437             lower case letters, now just substracts 32. This is ASCII-specific,
1438             but the whole concept of \cx is ASCII-specific, so it seems
1439             reasonable.
1440    
1441       (iii) PCRE was using its character types table to recognize decimal and
1442             hexadecimal digits in the pattern. This is silly, because it handles
1443             only 0-9, a-f, and A-F, but the character types table is locale-
1444             specific, which means strange things might happen. A private
1445             table is now used for this - though it costs 256 bytes, a table is
1446             much faster than multiple explicit tests. Of course, the standard
1447             character types table is still used for matching digits in subject
1448             strings against \d.
1449    
1450       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1451             ending in _t are). So I've renamed it as ESC_tee.
1452    
1453    3. The first argument for regexec() in the POSIX wrapper should have been
1454       defined as "const".
1455    
1456    4. Changed pcretest to use malloc() for its buffers so that they can be
1457       Electric Fenced for debugging.
1458    
1459    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1460       to read one or more bytes before the start of the subject string. Often this
1461       had no effect on PCRE's behaviour, but in some circumstances it could
1462       provoke a segmentation fault.
1463    
1464    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1465       to try to read one or more bytes before the start of the subject string.
1466    
1467    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1468       UTF-8 support could misbehave in various ways if the subject string
1469       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1470       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1471       back over UTF-8 characters.)
1472    
1473    
1474  Version 4.2 14-Apr-03  Version 4.2 14-Apr-03
1475  ---------------------  ---------------------
1476    

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