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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.1 12-Mar-07
5    ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other Autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The 132html script that I use to generate
25        HTML has been updated to handle .nf/.fi and to complain if it encounters
26        .br or .in.
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, with the name
30        config.h.generic, for the benefit of those who have to compile without
31        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
33     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
34        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
35        makevp.bat for the current PCRE, using the additional files
36        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
38     6. A Windows user reported a minor discrepancy with test 2, which turned out
39        to be caused by a trailing space on an input line that had got lost in his
40        copy. The trailing space was an accident, so I've just removed it.
42     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
43        that is needed.
45     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
46        as "const" (a) because they are and (b) because it helps the PHP
47        maintainers who have recently made a script to detect big data structures
48        in the php code that should be moved to the .rodata section. I remembered
49        to update Builducptable as well, so it won't revert if ucptable.h is ever
50        re-created.
52     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
53        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
54        order to be able to cut out the UTF-8 tables in the latter when UTF-8
55        support is not required. This saves 1.5-2K of code, which is important in
56        some applications.
58        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
59        so as not to refer to the tables, even though these functions will never be
60        called when UTF-8 support is disabled. Otherwise there are problems with a
61        shared library.
63    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
65        (a) It was defining its arguments as char * instead of void *.
67        (b) It was assuming that all moves were upwards in memory; this was true
68            a long time ago when I wrote it, but is no longer the case.
70        The emulated memove() is provided for those environments that have neither
71        memmove() nor bcopy(). I didn't think anyone used it these days, but that
72        is clearly not the case, as these two bugs were recently reported.
74    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
75        and Detrail to create the HTML documentation, the .txt form of the man
76        pages, and it removes trailing spaces from listed files. It also creates
77        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
78        case, it wraps all the #defines with #ifndefs. This script should be run
79        before "make dist".
81    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
82        with Unicode property support.
84        (a) For a maximizing quantifier, if the two different cases of the
85            character were of different lengths in their UTF-8 codings (there are
86            some cases like this - I found 11), and the matching function had to
87            back up over a mixture of the two cases, it incorrectly assumed they
88            were both the same length.
90        (b) When PCRE was configured to use the heap rather than the stack for
91            recursion during matching, it was not correctly preserving the data for
92            the other case of a UTF-8 character when checking ahead for a match
93            while processing a minimizing repeat. If the check also involved
94            matching a wide character, but failed, corruption could cause an
95            erroneous result when trying to check for a repeat of the original
96            character.
98    13. Some tidying changes to the testing mechanism:
100        (a) The RunTest script now detects the internal link size and whether there
101            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
102            values substituted by "configure". (The RunGrepTest script already did
103            this for UTF-8.) The configure.ac script no longer substitutes the
104            relevant variables.
106        (b) The debugging options /B and /D in pcretest show the compiled bytecode
107            with length and offset values. This means that the output is different
108            for different internal link sizes. Test 2 is skipped for link sizes
109            other than 2 because of this, bypassing the problem. Unfortunately,
110            there was also a test in test 3 (the locale tests) that used /B and
111            failed for link sizes other than 2. Rather than cut the whole test out,
112            I have added a new /Z option to pcretest that replaces the length and
113            offset values with spaces. This is now used to make test 3 independent
114            of link size. (Test 2 will be tidied up later.)
116    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
117        segmentation fault instead of returning the appropriate error message.
119    15. In multiline mode when the newline sequence was set to "any", the pattern
120        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
121        This doesn't seem right; it now treats the CRLF combination as the line
122        ending, and so does not match in that case. It's only a pattern such as ^$
123        that would hit this one: something like ^ABC$ would have failed after \r
124        and then tried again after \r\n.
126    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
127        in an attempt to make files that differ only in their line terminators
128        compare equal. This works on Linux.
130    17. Under certain error circumstances pcregrep might try to free random memory
131        as it exited. This is now fixed, thanks to valgrind.
133    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
134        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
135        was because its rules for how to advance for /g after matching an empty
136        string at the end of a line did not allow for this case. They now check for
137        it specially.
139    20. pcretest is supposed to handle patterns and data of any length, by
140        extending its buffers when necessary. It was getting this wrong when the
141        buffer for a data line had to be extended.
143    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
144        CRLF as a newline sequence.
147    Version 7.0 19-Dec-06
148    ---------------------
150     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
151        moving to gcc 4.1.1.
153     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
154        sys/time.h, which is documented as needed for this function. It doesn't
155        seem to matter on Linux, but it showed up on some releases of OS X.
157     3. It seems that there are systems where bytes whose values are greater than
158        127 match isprint() in the "C" locale. The "C" locale should be the
159        default when a C program starts up. In most systems, only ASCII printing
160        characters match isprint(). This difference caused the output from pcretest
161        to vary, making some of the tests fail. I have changed pcretest so that:
163        (a) When it is outputting text in the compiled version of a pattern, bytes
164            other than 32-126 are always shown as hex escapes.
166        (b) When it is outputting text that is a matched part of a subject string,
167            it does the same, unless a different locale has been set for the match
168            (using the /L modifier). In this case, it uses isprint() to decide.
170     4. Fixed a major bug that caused incorrect computation of the amount of memory
171        required for a compiled pattern when options that changed within the
172        pattern affected the logic of the preliminary scan that determines the
173        length. The relevant options are -x, and -i in UTF-8 mode. The result was
174        that the computed length was too small. The symptoms of this bug were
175        either the PCRE error "internal error: code overflow" from pcre_compile(),
176        or a glibc crash with a message such as "pcretest: free(): invalid next
177        size (fast)". Examples of patterns that provoked this bug (shown in
178        pcretest format) are:
180          /(?-x: )/x
181          /(?x)(?-x: \s*#\s*)/
182          /((?i)[\x{c0}])/8
183          /(?i:[\x{c0}])/8
185        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
186        is now done differently.
188     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
189        wrapper classes; (b) implement a new function in the C++ scanner that is
190        more efficient than the old way of doing things because it avoids levels of
191        recursion in the regex matching; (c) add a paragraph to the documentation
192        for the FullMatch() function.
194     6. The escape sequence \n was being treated as whatever was defined as
195        "newline". Not only was this contrary to the documentation, which states
196        that \n is character 10 (hex 0A), but it also went horribly wrong when
197        "newline" was defined as CRLF. This has been fixed.
199     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
200        was being set to -1 for the "end of line" case (supposedly a value that no
201        character can have). Though this value is never used (the check for end of
202        line is "zero bytes in current character"), it caused compiler complaints.
203        I've changed it to 0xffffffff.
205     8. In pcre_version.c, the version string was being built by a sequence of
206        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
207        string (as it is for production releases) called a macro with an empty
208        argument. The C standard says the result of this is undefined. The gcc
209        compiler treats it as an empty string (which was what was wanted) but it is
210        reported that Visual C gives an error. The source has been hacked around to
211        avoid this problem.
213     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
214        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
215        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
216        of them did).
218    10. Originally, pcretest opened its input and output without "b"; then I was
219        told that "b" was needed in some environments, so it was added for release
220        5.0 to both the input and output. (It makes no difference on Unix-like
221        systems.) Later I was told that it is wrong for the input on Windows. I've
222        now abstracted the modes into two macros, to make it easier to fiddle with
223        them, and removed "b" from the input mode under Windows.
225    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
227    12. Added -help and --help to pcretest as an official way of being reminded
228        of the options.
230    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
231        and pcrecpp.cc because they annoy compilers at high warning levels.
233    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
235    15. Fixed an occurrence of == in configure.ac that should have been = (shell
236        scripts are not C programs :-) and which was not noticed because it works
237        on Linux.
239    16. pcretest is supposed to handle any length of pattern and data line (as one
240        line or as a continued sequence of lines) by extending its input buffer if
241        necessary. This feature was broken for very long pattern lines, leading to
242        a string of junk being passed to pcre_compile() if the pattern was longer
243        than about 50K.
245    17. I have done a major re-factoring of the way pcre_compile() computes the
246        amount of memory needed for a compiled pattern. Previously, there was code
247        that made a preliminary scan of the pattern in order to do this. That was
248        OK when PCRE was new, but as the facilities have expanded, it has become
249        harder and harder to keep it in step with the real compile phase, and there
250        have been a number of bugs (see for example, 4 above). I have now found a
251        cunning way of running the real compile function in a "fake" mode that
252        enables it to compute how much memory it would need, while actually only
253        ever using a few hundred bytes of working memory and without too many
254        tests of the mode. This should make future maintenance and development
255        easier. A side effect of this work is that the limit of 200 on the nesting
256        depth of parentheses has been removed (though this was never a serious
257        limitation, I suspect). However, there is a downside: pcre_compile() now
258        runs more slowly than before (30% or more, depending on the pattern). I
259        hope this isn't a big issue. There is no effect on runtime performance.
261    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
262        newline (only possible for the last line of a file) and it was a
263        pattern that set a locale (followed by /Lsomething), pcretest crashed.
265    19. Added additional timing features to pcretest. (1) The -tm option now times
266        matching only, not compiling. (2) Both -t and -tm can be followed, as a
267        separate command line item, by a number that specifies the number of
268        repeats to use when timing. The default is 50000; this gives better
269        precision, but takes uncomfortably long for very large patterns.
271    20. Extended pcre_study() to be more clever in cases where a branch of a
272        subpattern has no definite first character. For example, (a*|b*)[cd] would
273        previously give no result from pcre_study(). Now it recognizes that the
274        first character must be a, b, c, or d.
276    21. There was an incorrect error "recursive call could loop indefinitely" if
277        a subpattern (or the entire pattern) that was being tested for matching an
278        empty string contained only one non-empty item after a nested subpattern.
279        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
280        incorrectly, because the \d was being skipped in the check.
282    22. The pcretest program now has a new pattern option /B and a command line
283        option -b, which is equivalent to adding /B to every pattern. This causes
284        it to show the compiled bytecode, without the additional information that
285        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
286        is the same as /B/I).
288    23. A new optimization is now able automatically to treat some sequences such
289        as a*b as a*+b. More specifically, if something simple (such as a character
290        or a simple class like \d) has an unlimited quantifier, and is followed by
291        something that cannot possibly match the quantified thing, the quantifier
292        is automatically "possessified".
294    24. A recursive reference to a subpattern whose number was greater than 39
295        went wrong under certain circumstances in UTF-8 mode. This bug could also
296        have affected the operation of pcre_study().
298    25. Realized that a little bit of performance could be had by replacing
299        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
301    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
303    27. Possessive quantifiers such as a++ were previously implemented by turning
304        them into atomic groups such as ($>a+). Now they have their own opcodes,
305        which improves performance. This includes the automatically created ones
306        from 23 above.
308    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
309        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
310        the first matched character to be a colon. This applied both to named and
311        numbered groups.
313    29. The ucpinternal.h header file was missing its idempotency #ifdef.
315    30. I was sent a "project" file called libpcre.a.dev which I understand makes
316        building PCRE on Windows easier, so I have included it in the distribution.
318    31. There is now a check in pcretest against a ridiculously large number being
319        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
320        loop, the loop is abandoned.
322    32. Forward references to subpatterns in conditions such as (?(2)...) where
323        subpattern 2 is defined later cause pcre_compile() to search forwards in
324        the pattern for the relevant set of parentheses. This search went wrong
325        when there were unescaped parentheses in a character class, parentheses
326        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
328    33. "Subroutine" calls and backreferences were previously restricted to
329        referencing subpatterns earlier in the regex. This restriction has now
330        been removed.
332    34. Added a number of extra features that are going to be in Perl 5.10. On the
333        whole, these are just syntactic alternatives for features that PCRE had
334        previously implemented using the Python syntax or my own invention. The
335        other formats are all retained for compatibility.
337        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
338            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
339            also .NET compatible.
341        (b) A recursion or subroutine call to a named group can now be defined as
342            (?&name) as well as (?P>name).
344        (c) A backreference to a named group can now be defined as \k<name> or
345            \k'name' as well as (?P=name). The new forms, as well as being in Perl
346            5.10, are also .NET compatible.
348        (d) A conditional reference to a named group can now use the syntax
349            (?(<name>) or (?('name') as well as (?(name).
351        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
352            groups (named and numbered) that are never evaluated inline, but can be
353            called as "subroutines" from elsewhere. In effect, the DEFINE condition
354            is always false. There may be only one alternative in such a group.
356        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
357            as the simple (?(R). The condition is true only if the most recent
358            recursion is that of the given number or name. It does not search out
359            through the entire recursion stack.
361        (g) The escape \gN or \g{N} has been added, where N is a positive or
362            negative number, specifying an absolute or relative reference.
364    35. Tidied to get rid of some further signed/unsigned compiler warnings and
365        some "unreachable code" warnings.
367    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
368        things, this adds five new scripts.
370    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
371        There were also incompatibilities regarding the handling of \Q..\E inside
372        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
373        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
375    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
376        matches an empty string, and forcibly breaks the loop. There were bugs in
377        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
378        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
379        separate and independent bugs (that affected different cases) have been
380        fixed.
382    39. Refactored the code to abolish the use of different opcodes for small
383        capturing bracket numbers. This is a tidy that I avoided doing when I
384        removed the limit on the number of capturing brackets for 3.5 back in 2001.
385        The new approach is not only tidier, it makes it possible to reduce the
386        memory needed to fix the previous bug (38).
388    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
389        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
390        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
391        mode.
393    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
394        report.
396    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
397        copy construction and assignment in the C++ wrapper.
399    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
400        couple of bugs that could have given wrong results in the "--newline=crlf"
401        case.
403    44. Added a number of casts and did some reorganization of signed/unsigned int
404        variables following suggestions from Dair Grant. Also renamed the variable
405        "this" as "item" because it is a C++ keyword.
407    45. Arranged for dftables to add
409          #include "pcre_internal.h"
411        to pcre_chartables.c because without it, gcc 4.x may remove the array
412        definition from the final binary if PCRE is built into a static library and
413        dead code stripping is activated.
415    46. For an unanchored pattern, if a match attempt fails at the start of a
416        newline sequence, and the newline setting is CRLF or ANY, and the next two
417        characters are CRLF, advance by two characters instead of one.
420    Version 6.7 04-Jul-06
421    ---------------------
423     1. In order to handle tests when input lines are enormously long, pcretest has
424        been re-factored so that it automatically extends its buffers when
425        necessary. The code is crude, but this _is_ just a test program. The
426        default size has been increased from 32K to 50K.
428     2. The code in pcre_study() was using the value of the re argument before
429        testing it for NULL. (Of course, in any sensible call of the function, it
430        won't be NULL.)
432     3. The memmove() emulation function in pcre_internal.h, which is used on
433        systems that lack both memmove() and bcopy() - that is, hardly ever -
434        was missing a "static" storage class specifier.
436     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
437        containing an extended class (one that cannot be represented by a bitmap
438        because it contains high-valued characters or Unicode property items, e.g.
439        [\pZ]). Almost always one would set UTF-8 mode when processing such a
440        pattern, but PCRE should not loop if you do not (it no longer does).
441        [Detail: two cases were found: (a) a repeated subpattern containing an
442        extended class; (b) a recursive reference to a subpattern that followed a
443        previous extended class. It wasn't skipping over the extended class
444        correctly when UTF-8 mode was not set.]
446     5. A negated single-character class was not being recognized as fixed-length
447        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
448        compile error "lookbehind assertion is not fixed length".
450     6. The RunPerlTest auxiliary script was showing an unexpected difference
451        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
452        write a Perl script that can interpret lines of an input file either as
453        byte characters or as UTF-8, which is what "perltest" was being required to
454        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
455        can't do is switch easily at run time between having the "use utf8;" pragma
456        or not. In the end, I fudged it by using the RunPerlTest script to insert
457        "use utf8;" explicitly for the UTF-8 tests.
459     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
460        the end of the subject string, contrary to the documentation and to what
461        Perl does. This was true of both matching functions. Now it matches only at
462        the start of the subject and immediately after *internal* newlines.
464     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
465        a pointer to an int instead of a pointer to an unsigned long int. This
466        caused problems on 64-bit systems.
468     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
469        instance of the 'standard' template library not being so standard".
471    10. There was no check on the number of named subpatterns nor the maximum
472        length of a subpattern name. The product of these values is used to compute
473        the size of the memory block for a compiled pattern. By supplying a very
474        long subpattern name and a large number of named subpatterns, the size
475        computation could be caused to overflow. This is now prevented by limiting
476        the length of names to 32 characters, and the number of named subpatterns
477        to 10,000.
479    11. Subpatterns that are repeated with specific counts have to be replicated in
480        the compiled pattern. The size of memory for this was computed from the
481        length of the subpattern and the repeat count. The latter is limited to
482        65535, but there was no limit on the former, meaning that integer overflow
483        could in principle occur. The compiled length of a repeated subpattern is
484        now limited to 30,000 bytes in order to prevent this.
486    12. Added the optional facility to have named substrings with the same name.
488    13. Added the ability to use a named substring as a condition, using the
489        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
490        are numbers (not recommended). Forward references are permitted.
492    14. Added forward references in named backreferences (if you see what I mean).
494    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
495        pattern could run off the end of the subject. For example, the pattern
496        "(?s)(.{1,5})"8 did this with the subject "ab".
498    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
499        PCRE_CASELESS was set when matching characters that were quantified with ?
500        or *.
502    17. A character class other than a single negated character that had a minimum
503        but no maximum quantifier - for example [ab]{6,} - was not handled
504        correctly by pce_dfa_exec(). It would match only one character.
506    18. A valid (though odd) pattern that looked like a POSIX character
507        class but used an invalid character after [ (for example [[,abc,]]) caused
508        pcre_compile() to give the error "Failed: internal error: code overflow" or
509        in some cases to crash with a glibc free() error. This could even happen if
510        the pattern terminated after [[ but there just happened to be a sequence of
511        letters, a binary zero, and a closing ] in the memory that followed.
513    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
514        over the years. Originally (before any Unicode support), just the bottom 8
515        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
516        output from "man perlunicode" includes this:
518          The regular expression compiler produces polymorphic opcodes.  That
519          is, the pattern adapts to the data and automatically switches to
520          the Unicode character scheme when presented with Unicode data--or
521          instead uses a traditional byte scheme when presented with byte
522          data.
524        Sadly, a wide octal escape does not cause a switch, and in a string with
525        no other multibyte characters, these octal escapes are treated as before.
526        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
527        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
528        Unicode string.
530        I have not perpetrated such confusion in PCRE. Up till now, it took just
531        the bottom 8 bits, as in old Perl. I have now made octal escapes with
532        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
533        translate to the appropriate multibyte character.
535    29. Applied some refactoring to reduce the number of warnings from Microsoft
536        and Borland compilers. This has included removing the fudge introduced
537        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
538        a warning about an unused variable.
540    21. PCRE has not included VT (character 0x0b) in the set of whitespace
541        characters since release 4.0, because Perl (from release 5.004) does not.
542        [Or at least, is documented not to: some releases seem to be in conflict
543        with the documentation.] However, when a pattern was studied with
544        pcre_study() and all its branches started with \s, PCRE still included VT
545        as a possible starting character. Of course, this did no harm; it just
546        caused an unnecessary match attempt.
548    22. Removed a now-redundant internal flag bit that recorded the fact that case
549        dependency changed within the pattern. This was once needed for "required
550        byte" processing, but is no longer used. This recovers a now-scarce options
551        bit. Also moved the least significant internal flag bit to the most-
552        significant bit of the word, which was not previously used (hangover from
553        the days when it was an int rather than a uint) to free up another bit for
554        the future.
556    23. Added support for CRLF line endings as well as CR and LF. As well as the
557        default being selectable at build time, it can now be changed at runtime
558        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
559        specify that it is scanning data with non-default line endings.
561    24. Changed the definition of CXXLINK to make it agree with the definition of
562        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
564    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
565        recursions. This makes a big different to stack usage for some patterns.
567    26. If a subpattern containing a named recursion or subroutine reference such
568        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
569        the space required for the compiled pattern went wrong and gave too small a
570        value. Depending on the environment, this could lead to "Failed: internal
571        error: code overflow at offset 49" or "glibc detected double free or
572        corruption" errors.
574    27. Applied patches from Google (a) to support the new newline modes and (b) to
575        advance over multibyte UTF-8 characters in GlobalReplace.
577    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
578        difference for some implementation of PCRE in some Windows version.
580    29. Added some extra testing facilities to pcretest:
582        \q<number>   in a data line sets the "match limit" value
583        \Q<number>   in a data line sets the "match recursion limt" value
584        -S <number>  sets the stack size, where <number> is in megabytes
586        The -S option isn't available for Windows.
589    Version 6.6 06-Feb-06
590    ---------------------
592     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
593        in pcreposix.h. I have copied the definition from pcre.h.
595     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
596        because pcre.h is no longer a built file.
598     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
599        not normally included in the compiled code.
602    Version 6.5 01-Feb-06
603    ---------------------
605     1. When using the partial match feature with pcre_dfa_exec(), it was not
606        anchoring the second and subsequent partial matches at the new starting
607        point. This could lead to incorrect results. For example, with the pattern
608        /1234/, partially matching against "123" and then "a4" gave a match.
610     2. Changes to pcregrep:
612        (a) All non-match returns from pcre_exec() were being treated as failures
613            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
614            error message is output. Some extra information is given for the
615            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
616            probably the only errors that are likely to be caused by users (by
617            specifying a regex that has nested indefinite repeats, for instance).
618            If there are more than 20 of these errors, pcregrep is abandoned.
620        (b) A binary zero was treated as data while matching, but terminated the
621            output line if it was written out. This has been fixed: binary zeroes
622            are now no different to any other data bytes.
624        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
625            used to set a locale for matching. The --locale=xxxx long option has
626            been added (no short equivalent) to specify a locale explicitly on the
627            pcregrep command, overriding the environment variables.
629        (d) When -B was used with -n, some line numbers in the output were one less
630            than they should have been.
632        (e) Added the -o (--only-matching) option.
634        (f) If -A or -C was used with -c (count only), some lines of context were
635            accidentally printed for the final match.
637        (g) Added the -H (--with-filename) option.
639        (h) The combination of options -rh failed to suppress file names for files
640            that were found from directory arguments.
642        (i) Added the -D (--devices) and -d (--directories) options.
644        (j) Added the -F (--fixed-strings) option.
646        (k) Allow "-" to be used as a file name for -f as well as for a data file.
648        (l) Added the --colo(u)r option.
650        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
651            is not present by default.
653     3. A nasty bug was discovered in the handling of recursive patterns, that is,
654        items such as (?R) or (?1), when the recursion could match a number of
655        alternatives. If it matched one of the alternatives, but subsequently,
656        outside the recursion, there was a failure, the code tried to back up into
657        the recursion. However, because of the way PCRE is implemented, this is not
658        possible, and the result was an incorrect result from the match.
660        In order to prevent this happening, the specification of recursion has
661        been changed so that all such subpatterns are automatically treated as
662        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
664     4. I had overlooked the fact that, in some locales, there are characters for
665        which isalpha() is true but neither isupper() nor islower() are true. In
666        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
667        and ordfeminine) are like this. This affected the treatment of \w and \W
668        when they appeared in character classes, but not when they appeared outside
669        a character class. The bit map for "word" characters is now created
670        separately from the results of isalnum() instead of just taking it from the
671        upper, lower, and digit maps. (Plus the underscore character, of course.)
673     5. The above bug also affected the handling of POSIX character classes such as
674        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
675        permanent tables. Instead, the bit maps for such a class were previously
676        created as the appropriate unions of the upper, lower, and digit bitmaps.
677        Now they are created by subtraction from the [[:word:]] class, which has
678        its own bitmap.
680     6. The [[:blank:]] character class matches horizontal, but not vertical space.
681        It is created by subtracting the vertical space characters (\x09, \x0a,
682        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
683        subtraction was done in the overall bitmap for a character class, meaning
684        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
685        be recognized. This bug has been fixed.
687     7. Patches from the folks at Google:
689          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
690          real life, but is still worth protecting against".
692          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
693          regular expressions".
695          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
696          have it.
698          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
699          "configure" and the latter not, in order to fix a problem somebody had
700          with compiling the Arg class on HP-UX.
702          (e) Improve the error-handling of the C++ wrapper a little bit.
704          (f) New tests for checking recursion limiting.
706     8. The pcre_memmove() function, which is used only if the environment does not
707        have a standard memmove() function (and is therefore rarely compiled),
708        contained two bugs: (a) use of int instead of size_t, and (b) it was not
709        returning a result (though PCRE never actually uses the result).
711     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
712        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
713        returned instead of calling malloc() with an overflowing number that would
714        most likely cause subsequent chaos.
716    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
718    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
719        with this option is matched, the nmatch and pmatch options of regexec() are
720        ignored.
722    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
723        provided in case anyone wants to the the POSIX interface with UTF-8
724        strings.
726    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
727        C++ linking (needed for some HP-UX environments).
729    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
730        (unused parameter) and in the pcre_printint() function (omitted "default"
731        switch label when the default is to do nothing).
733    15. Added some code to make it possible, when PCRE is compiled as a C++
734        library, to replace subject pointers for pcre_exec() with a smart pointer
735        class, thus making it possible to process discontinuous strings.
737    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
738        much the same function. They were added by different people who were trying
739        to make PCRE easy to compile on non-Unix systems. It has been suggested
740        that PCRE_EXPORT be abolished now that there is more automatic apparatus
741        for compiling on Windows systems. I have therefore replaced it with
742        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
743        defaults to "extern" for C or "extern C" for C++, which works fine on
744        Unix-like systems. It is now possible to override the value of PCRE_DATA_
745        SCOPE with something explicit in config.h. In addition:
747        (a) pcreposix.h still had just "extern" instead of either of these macros;
748            I have replaced it with PCRE_DATA_SCOPE.
750        (b) Functions such as _pcre_xclass(), which are internal to the library,
751            but external in the C sense, all had PCRE_EXPORT in their definitions.
752            This is apparently wrong for the Windows case, so I have removed it.
753            (It makes no difference on Unix-like systems.)
755    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
756        of recursive calls to match(). This is different to MATCH_LIMIT because
757        that limits the total number of calls to match(), not all of which increase
758        the depth of recursion. Limiting the recursion depth limits the amount of
759        stack (or heap if NO_RECURSE is set) that is used. The default can be set
760        when PCRE is compiled, and changed at run time. A patch from Google adds
761        this functionality to the C++ interface.
763    18. Changes to the handling of Unicode character properties:
765        (a) Updated the table to Unicode 4.1.0.
767        (b) Recognize characters that are not in the table as "Cn" (undefined).
769        (c) I revised the way the table is implemented to a much improved format
770            which includes recognition of ranges. It now supports the ranges that
771            are defined in UnicodeData.txt, and it also amalgamates other
772            characters into ranges. This has reduced the number of entries in the
773            table from around 16,000 to around 3,000, thus reducing its size
774            considerably. I realized I did not need to use a tree structure after
775            all - a binary chop search is just as efficient. Having reduced the
776            number of entries, I extended their size from 6 bytes to 8 bytes to
777            allow for more data.
779        (d) Added support for Unicode script names via properties such as \p{Han}.
781    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
782        matching that character.
784    20. When matching a repeated Unicode property with a minimum greater than zero,
785        (for example \pL{2,}), PCRE could look past the end of the subject if it
786        reached it while seeking the minimum number of characters. This could
787        happen only if some of the characters were more than one byte long, because
788        there is a check for at least the minimum number of bytes.
790    21. Refactored the implementation of \p and \P so as to be more general, to
791        allow for more different types of property in future. This has changed the
792        compiled form incompatibly. Anybody with saved compiled patterns that use
793        \p or \P will have to recompile them.
795    22. Added "Any" and "L&" to the supported property types.
797    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
798        but give a compile time error if the value is greater than 0xff.
800    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
801        accidentally not being installed or uninstalled.
803    25. The pcre.h file was built from pcre.h.in, but the only changes that were
804        made were to insert the current release number. This seemed silly, because
805        it made things harder for people building PCRE on systems that don't run
806        "configure". I have turned pcre.h into a distributed file, no longer built
807        by "configure", with the version identification directly included. There is
808        no longer a pcre.h.in file.
810        However, this change necessitated a change to the pcre-config script as
811        well. It is built from pcre-config.in, and one of the substitutions was the
812        release number. I have updated configure.ac so that ./configure now finds
813        the release number by grepping pcre.h.
815    26. Added the ability to run the tests under valgrind.
818    Version 6.4 05-Sep-05
819    ---------------------
821     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
822        "--" to be printed when multiple files were scanned, even when none of the
823        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
824        consider it to be a bug, and have restored the previous behaviour.
826     2. A couple of code tidies to get rid of compiler warnings.
828     3. The pcretest program used to cheat by referring to symbols in the library
829        whose names begin with _pcre_. These are internal symbols that are not
830        really supposed to be visible externally, and in some environments it is
831        possible to suppress them. The cheating is now confined to including
832        certain files from the library's source, which is a bit cleaner.
834     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
835        file's purpose clearer.
837     5. Reorganized pcre_ucp_findchar().
840    Version 6.3 15-Aug-05
841    ---------------------
843     1. The file libpcre.pc.in did not have general read permission in the tarball.
845     2. There were some problems when building without C++ support:
847        (a) If C++ support was not built, "make install" and "make test" still
848            tried to test it.
850        (b) There were problems when the value of CXX was explicitly set. Some
851            changes have been made to try to fix these, and ...
853        (c) --disable-cpp can now be used to explicitly disable C++ support.
855        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
856            backslash in a target when C++ was disabled. This confuses some
857            versions of "make", apparently. Using an intermediate variable solves
858            this. (Same for CPP_LOBJ.)
860     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
861        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
862        necessary on certain architectures.
864     4. Added a setting of -export-symbols-regex to the link command to remove
865        those symbols that are exported in the C sense, but actually are local
866        within the library, and not documented. Their names all begin with
867        "_pcre_". This is not a perfect job, because (a) we have to except some
868        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
869        available (and never for static libraries). I have made a note to try to
870        find a way round (a) in the future.
873    Version 6.2 01-Aug-05
874    ---------------------
876     1. There was no test for integer overflow of quantifier values. A construction
877        such as {1111111111111111} would give undefined results. What is worse, if
878        a minimum quantifier for a parenthesized subpattern overflowed and became
879        negative, the calculation of the memory size went wrong. This could have
880        led to memory overwriting.
882     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
884     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
885        operating environments where this matters.
887     4. Applied Giuseppe Maxia's patch to add additional features for controlling
888        PCRE options from within the C++ wrapper.
890     5. Named capturing subpatterns were not being correctly counted when a pattern
891        was compiled. This caused two problems: (a) If there were more than 100
892        such subpatterns, the calculation of the memory needed for the whole
893        compiled pattern went wrong, leading to an overflow error. (b) Numerical
894        back references of the form \12, where the number was greater than 9, were
895        not recognized as back references, even though there were sufficient
896        previous subpatterns.
898     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
899        versions of gcc, e.g. 2.95.4.
902    Version 6.1 21-Jun-05
903    ---------------------
905     1. There was one reference to the variable "posix" in pcretest.c that was not
906        surrounded by "#if !defined NOPOSIX".
908     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
909        the cross-check on the old pcre_info() function, for the benefit of the
910        cut-down version of PCRE that is currently imported into Exim.
912     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
913        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
914        patterns that start (?i) but I don't think that matters. The use of (?i) is
915        just an example; this all applies to the other options as well.
917     4. Since libtool seems to echo the compile commands it is issuing, the output
918        from "make" can be reduced a bit by putting "@" in front of each libtool
919        compile command.
921     5. Patch from the folks at Google for configure.in to be a bit more thorough
922        in checking for a suitable C++ installation before trying to compile the
923        C++ stuff. This should fix a reported problem when a compiler was present,
924        but no suitable headers.
926     6. The man pages all had just "PCRE" as their title. I have changed them to
927        be the relevant file name. I have also arranged that these names are
928        retained in the file doc/pcre.txt, which is a concatenation in text format
929        of all the man pages except the little individual ones for each function.
931     7. The NON-UNIX-USE file had not been updated for the different set of source
932        files that come with release 6. I also added a few comments about the C++
933        wrapper.
936    Version 6.0 07-Jun-05
937    ---------------------
939     1. Some minor internal re-organization to help with my DFA experiments.
941     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
942        didn't matter for the library itself when fully configured, but did matter
943        when compiling without UCP support, or within Exim, where the ucp files are
944        not imported.
946     3. Refactoring of the library code to split up the various functions into
947        different source modules. The addition of the new DFA matching code (see
948        below) to a single monolithic source would have made it really too
949        unwieldy, quite apart from causing all the code to be include in a
950        statically linked application, when only some functions are used. This is
951        relevant even without the DFA addition now that patterns can be compiled in
952        one application and matched in another.
954        The downside of splitting up is that there have to be some external
955        functions and data tables that are used internally in different modules of
956        the library but which are not part of the API. These have all had their
957        names changed to start with "_pcre_" so that they are unlikely to clash
958        with other external names.
960     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
961        a different (DFA) algorithm. Although it is slower than the original
962        function, it does have some advantages for certain types of matching
963        problem.
965     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
966        including restarting after a partial match.
968     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
969        defined when compiling for Windows was sent to me. I have put it into the
970        code, though I have no means of testing or verifying it.
972     7. Added the pcre_refcount() auxiliary function.
974     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
975        match before or at the first newline in the subject string. In pcretest,
976        the /f option on a pattern can be used to set this.
978     9. A repeated \w when used in UTF-8 mode with characters greater than 256
979        would behave wrongly. This has been present in PCRE since release 4.0.
981    10. A number of changes to the pcregrep command:
983        (a) Refactored how -x works; insert ^(...)$ instead of setting
984            PCRE_ANCHORED and checking the length, in preparation for adding
985            something similar for -w.
987        (b) Added the -w (match as a word) option.
989        (c) Refactored the way lines are read and buffered so as to have more
990            than one at a time available.
992        (d) Implemented a pcregrep test script.
994        (e) Added the -M (multiline match) option. This allows patterns to match
995            over several lines of the subject. The buffering ensures that at least
996            8K, or the rest of the document (whichever is the shorter) is available
997            for matching (and similarly the previous 8K for lookbehind assertions).
999        (f) Changed the --help output so that it now says
1001              -w, --word-regex(p)
1003            instead of two lines, one with "regex" and the other with "regexp"
1004            because that confused at least one person since the short forms are the
1005            same. (This required a bit of code, as the output is generated
1006            automatically from a table. It wasn't just a text change.)
1008        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1009            option but starts with a hyphen. Could be a pattern or a path name
1010            starting with a hyphen, for instance.
1012        (h) "-" can be given as a file name to represent stdin.
1014        (i) When file names are being printed, "(standard input)" is used for
1015            the standard input, for compatibility with GNU grep. Previously
1016            "<stdin>" was used.
1018        (j) The option --label=xxx can be used to supply a name to be used for
1019            stdin when file names are being printed. There is no short form.
1021        (k) Re-factored the options decoding logic because we are going to add
1022            two more options that take data. Such options can now be given in four
1023            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1025        (l) Added the -A, -B, and -C options for requesting that lines of context
1026            around matches be printed.
1028        (m) Added the -L option to print the names of files that do not contain
1029            any matching lines, that is, the complement of -l.
1031        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1032            continue to scan other files.
1034        (o) The -s option was incorrectly implemented. For compatibility with other
1035            greps, it now suppresses the error message for a non-existent or non-
1036            accessible file (but not the return code). There is a new option called
1037            -q that suppresses the output of matching lines, which was what -s was
1038            previously doing.
1040        (p) Added --include and --exclude options to specify files for inclusion
1041            and exclusion when recursing.
1043    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1044        Hopefully, it now does.
1046    12. Missing cast in pcre_study().
1048    13. Added an "uninstall" target to the makefile.
1050    14. Replaced "extern" in the function prototypes in Makefile.in with
1051        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1052        world, but is set differently for Windows.
1054    15. Added a second compiling function called pcre_compile2(). The only
1055        difference is that it has an extra argument, which is a pointer to an
1056        integer error code. When there is a compile-time failure, this is set
1057        non-zero, in addition to the error test pointer being set to point to an
1058        error message. The new argument may be NULL if no error number is required
1059        (but then you may as well call pcre_compile(), which is now just a
1060        wrapper). This facility is provided because some applications need a
1061        numeric error indication, but it has also enabled me to tidy up the way
1062        compile-time errors are handled in the POSIX wrapper.
1064    16. Added VPATH=.libs to the makefile; this should help when building with one
1065        prefix path and installing with another. (Or so I'm told by someone who
1066        knows more about this stuff than I do.)
1068    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1069        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1070        match everything, including newlines. This is not POSIX-compatible, but
1071        somebody wanted the feature. From pcretest it can be activated by using
1072        both the P and the s flags.
1074    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1076    19. libpcre.pc was being incorrectly installed as executable.
1078    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1079        it now also looks for '\r' so that it will work unmodified on Windows.
1081    21. Added Google's contributed C++ wrapper to the distribution.
1083    22. Added some untidy missing memory free() calls in pcretest, to keep
1084        Electric Fence happy when testing.
1088    Version 5.0 13-Sep-04
1089    ---------------------
1091     1. Internal change: literal characters are no longer packed up into items
1092        containing multiple characters in a single byte-string. Each character
1093        is now matched using a separate opcode. However, there may be more than one
1094        byte in the character in UTF-8 mode.
1096     2. The pcre_callout_block structure has two new fields: pattern_position and
1097        next_item_length. These contain the offset in the pattern to the next match
1098        item, and its length, respectively.
1100     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1101        insertion of callouts before each pattern item. Added the /C option to
1102        pcretest to make use of this.
1104     4. On the advice of a Windows user, the lines
1106          #if defined(_WIN32) || defined(WIN32)
1107          _setmode( _fileno( stdout ), 0x8000 );
1108          #endif  /* defined(_WIN32) || defined(WIN32) */
1110        have been added to the source of pcretest. This apparently does useful
1111        magic in relation to line terminators.
1113     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1114        for the benefit of those environments where the "b" makes a difference.
1116     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1117        to know about it. I have put a hack into configure.in that adds in code
1118        to set GCC=yes if CC=icc. This seems to end up at a point in the
1119        generated configure script that is early enough to affect the setting of
1120        compiler options, which is what is needed, but I have no means of testing
1121        whether it really works. (The user who reported this had patched the
1122        generated configure script, which of course I cannot do.)
1124        LATER: After change 22 below (new libtool files), the configure script
1125        seems to know about icc (and also ecc). Therefore, I have commented out
1126        this hack in configure.in.
1128     7. Added support for pkg-config (2 patches were sent in).
1130     8. Negated POSIX character classes that used a combination of internal tables
1131        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1132        [[:^ascii]]. Typically, they would match almost any characters. The other
1133        POSIX classes were not broken in this way.
1135     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1136        to find the match, as PCRE was deluded into thinking that the match had to
1137        start at the start point or following a newline. The same bug applied to
1138        patterns with negative forward assertions or any backward assertions
1139        preceding ".*" at the start, unless the pattern required a fixed first
1140        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1142    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1143        starting at the last subject character, bytes beyond the end of the subject
1144        string were read.
1146    11. Renamed the variable "class" as "classbits" to make life easier for C++
1147        users. (Previously there was a macro definition, but it apparently wasn't
1148        enough.)
1150    12. Added the new field "tables" to the extra data so that tables can be passed
1151        in at exec time, or the internal tables can be re-selected. This allows
1152        a compiled regex to be saved and re-used at a later time by a different
1153        program that might have everything at different addresses.
1155    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1156        -R library as well as a -L library.
1158    14. The debugging options of pcretest (-d on the command line or D on a
1159        pattern) showed incorrect output for anything following an extended class
1160        that contained multibyte characters and which was followed by a quantifier.
1162    15. Added optional support for general category Unicode character properties
1163        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1164        support. It adds about 90K to the size of the library. The meanings of the
1165        inbuilt class escapes such as \d and \s have NOT been changed.
1167    16. Updated pcredemo.c to include calls to free() to release the memory for the
1168        compiled pattern.
1170    17. The generated file chartables.c was being created in the source directory
1171        instead of in the building directory. This caused the build to fail if the
1172        source directory was different from the building directory, and was
1173        read-only.
1175    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1176        file. No doubt somebody will tell me if they don't make sense... Also added
1177        Dan Mooney's comments about building on OpenVMS.
1179    19. Added support for partial matching via the PCRE_PARTIAL option for
1180        pcre_exec() and the \P data escape in pcretest.
1182    20. Extended pcretest with 3 new pattern features:
1184        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1185              write the compiled pattern to the file whose name is "rest-of-line".
1186              This is a straight binary dump of the data, with the saved pointer to
1187              the character tables forced to be NULL. The study data, if any, is
1188              written too. After writing, pcretest reads a new pattern.
1190        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1191              compiled pattern from the given file. There must not be any
1192              occurrences of "<" in the file name (pretty unlikely); if there are,
1193              pcretest will instead treat the initial "<" as a pattern delimiter.
1194              After reading in the pattern, pcretest goes on to read data lines as
1195              usual.
1197        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1198              and 16-bit fields in a compiled pattern, to simulate a pattern that
1199              was compiled on a host of opposite endianness.
1201    21. The pcre-exec() function can now cope with patterns that were compiled on
1202        hosts of opposite endianness, with this restriction:
1204          As for any compiled expression that is saved and used later, the tables
1205          pointer field cannot be preserved; the extra_data field in the arguments
1206          to pcre_exec() should be used to pass in a tables address if a value
1207          other than the default internal tables were used at compile time.
1209    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1210        now diagnosed as an error. Previously, most of the time, a negative number
1211        would have been treated as zero, but if in addition "ovector" was passed as
1212        NULL, a crash could occur.
1214    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1215        new versions from the libtool 1.5 distribution (the last one is a copy of
1216        a file called libtool.m4). This seems to have fixed the need to patch
1217        "configure" to support Darwin 1.3 (which I used to do). However, I still
1218        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1219        workstation).
1221    24. Changed the PCRE licence to be the more standard "BSD" licence.
1224    Version 4.5 01-Dec-03
1225    ---------------------
1227     1. There has been some re-arrangement of the code for the match() function so
1228        that it can be compiled in a version that does not call itself recursively.
1229        Instead, it keeps those local variables that need separate instances for
1230        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1231        needs to "recurse". Keeping track of where control must go is done by means
1232        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1233        hide most of the details from the main code, and operates only if
1234        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1235        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1236        operating.
1238        To make it easier for callers to provide specially tailored get/free
1239        functions for this usage, two new functions, pcre_stack_malloc, and
1240        pcre_stack_free, are used. They are always called in strict stacking order,
1241        and the size of block requested is always the same.
1243        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1244        PCRE has been compiled to use the stack or the heap for recursion. The
1245        -C option of pcretest uses this to show which version is compiled.
1247        A new data escape \S, is added to pcretest; it causes the amounts of store
1248        obtained and freed by both kinds of malloc/free at match time to be added
1249        to the output.
1251     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1252        what's available on my current Linux desktop machine.
1254     3. When matching a UTF-8 string, the test for a valid string at the start has
1255        been extended. If start_offset is not zero, PCRE now checks that it points
1256        to a byte that is the start of a UTF-8 character. If not, it returns
1257        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1258        this is necessary because there may be backward assertions in the pattern.
1259        When matching the same subject several times, it may save resources to use
1260        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1262     4. The code for checking the validity of UTF-8 strings has been tightened so
1263        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1264        containing "overlong sequences".
1266     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1267        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1268        should have been "&", but it just so happened that all the cases this let
1269        through by mistake were picked up later in the function.
1271     6. I had used a variable called "isblank" - this is a C99 function, causing
1272        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1274     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1275        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1276        so the version is shown; (c) stop "make test" echoing "./RunTest".
1278     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1280     9. The prototype for memmove() for systems that don't have it was using
1281        size_t, but the inclusion of the header that defines size_t was later. I've
1282        moved the #includes for the C headers earlier to avoid this.
1284    10. Added some adjustments to the code to make it easier to compiler on certain
1285        special systems:
1287          (a) Some "const" qualifiers were missing.
1288          (b) Added the macro EXPORT before all exported functions; by default this
1289              is defined to be empty.
1290          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1291              that it reads its output file name as an argument instead of writing
1292              to the standard output and assuming this can be redirected.
1294    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1295        class containing characters with values greater than 255, PCRE compilation
1296        went into a loop.
1298    12. A recursive reference to a subpattern that was within another subpattern
1299        that had a minimum quantifier of zero caused PCRE to crash. For example,
1300        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1301        recursion. If the recursively-called subpattern itself had a zero repeat,
1302        that was OK.
1304    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1305        buffer into which it was copied (for escape processing) was still set at
1306        1024, so long lines caused crashes.
1308    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1309        "internal error: code overflow...". This applied to any character class
1310        that was followed by a possessive quantifier.
1312    15. Modified the Makefile to add libpcre.la as a prerequisite for
1313        libpcreposix.la because I was told this is needed for a parallel build to
1314        work.
1316    16. If a pattern that contained .* following optional items at the start was
1317        studied, the wrong optimizing data was generated, leading to matching
1318        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1319        matching string must start with a or b or c. The correct conclusion for
1320        this pattern is that a match can start with any character.
1323    Version 4.4 13-Aug-03
1324    ---------------------
1326     1. In UTF-8 mode, a character class containing characters with values between
1327        127 and 255 was not handled correctly if the compiled pattern was studied.
1328        In fixing this, I have also improved the studying algorithm for such
1329        classes (slightly).
1331     2. Three internal functions had redundant arguments passed to them. Removal
1332        might give a very teeny performance improvement.
1334     3. Documentation bug: the value of the capture_top field in a callout is *one
1335        more than* the number of the hightest numbered captured substring.
1337     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1338        in incorrectly linking with a previously installed version. They now link
1339        explicitly with libpcre.la.
1341     5. configure.in no longer needs to recognize Cygwin specially.
1343     6. A problem in pcre.in for Windows platforms is fixed.
1345     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1346        pcretest, it used to include the size of the study block as part of its
1347        output. Unfortunately, the structure contains a field that has a different
1348        size on different hardware architectures. This meant that the tests that
1349        showed this size failed. As the block is currently always of a fixed size,
1350        this information isn't actually particularly useful in pcretest output, so
1351        I have just removed it.
1353     8. Three pre-processor statements accidentally did not start in column 1.
1354        Sadly, there are *still* compilers around that complain, even though
1355        standard C has not required this for well over a decade. Sigh.
1357     9. In pcretest, the code for checking callouts passed small integers in the
1358        callout_data field, which is a void * field. However, some picky compilers
1359        complained about the casts involved for this on 64-bit systems. Now
1360        pcretest passes the address of the small integer instead, which should get
1361        rid of the warnings.
1363    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1364        both compile and run time, and gives an error if an invalid UTF-8 sequence
1365        is found. There is a option for disabling this check in cases where the
1366        string is known to be correct and/or the maximum performance is wanted.
1368    11. In response to a bug report, I changed one line in Makefile.in from
1370            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1371        to
1372            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1374        to look similar to other lines, but I have no way of telling whether this
1375        is the right thing to do, as I do not use Windows. No doubt I'll get told
1376        if it's wrong...
1379  Version 4.3 21-May-03  Version 4.3 21-May-03
1380  ---------------------  ---------------------

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