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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.2 01-May-07
5    ---------------------
6    
7  Version 1.09 28 Apr-98   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
1475    ---------------------
1476    
1477    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1478    
1479    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1480         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1481         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1482         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1483         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1484           and BUILD_EXEEXT
1485         Note: automatic setting of the BUILD variables is not yet working
1486         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1487           compile-time but not at link-time
1488         [LINK]: use for linking executables only
1489         make different versions for Windows and non-Windows
1490         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1491           libraries
1492         [LINK_FOR_BUILD]: new variable
1493         [OBJEXT]: use throughout
1494         [EXEEXT]: use throughout
1495         <winshared>: new target
1496         <wininstall>: new target
1497         <dftables.o>: use native compiler
1498         <dftables>: use native linker
1499         <install>: handle Windows platform correctly
1500         <clean>: ditto
1501         <check>: ditto
1502         copy DLL to top builddir before testing
1503    
1504       As part of these changes, -no-undefined was removed again. This was reported
1505       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1506       in any case.
1507    
1508    3. Some tidies to get rid of compiler warnings:
1509    
1510       . In the match_data structure, match_limit was an unsigned long int, whereas
1511         match_call_count was an int. I've made them both unsigned long ints.
1512    
1513       . In pcretest the fact that a const uschar * doesn't automatically cast to
1514         a void * provoked a warning.
1515    
1516       . Turning on some more compiler warnings threw up some "shadow" variables
1517         and a few more missing casts.
1518    
1519    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1520       option, a class that contained a single character with a value between 128
1521       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1522    
1523    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1524       option, a class that contained several characters, but with at least one
1525       whose value was between 128 and 255 caused PCRE to crash.
1526    
1527    
1528    Version 4.1 12-Mar-03
1529    ---------------------
1530    
1531    1. Compiling with gcc -pedantic found a couple of places where casts were
1532    needed, and a string in dftables.c that was longer than standard compilers are
1533    required to support.
1534    
1535    2. Compiling with Sun's compiler found a few more places where the code could
1536    be tidied up in order to avoid warnings.
1537    
1538    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1539    first of these names is deprecated in the latest Autoconf in favour of the name
1540    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1541    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1542    analogy I have changed it to CFLAGS_FOR_BUILD.
1543    
1544    4. Added -no-undefined to the linking command in the Makefile, because this is
1545    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1546    linking step for the pcreposix library.
1547    
1548    5. PCRE was failing to diagnose the case of two named groups with the same
1549    name.
1550    
1551    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1552    literal character that is needed in the subject for a match, and scans along to
1553    ensure that it is present before embarking on the full matching process. This
1554    saves time in cases of nested unlimited repeats that are never going to match.
1555    Problem: the scan can take a lot of time if the subject is very long (e.g.
1556    megabytes), thus penalizing straightforward matches. It is now done only if the
1557    amount of subject to be scanned is less than 1000 bytes.
1558    
1559    7. A lesser problem with the same optimization is that it was recording the
1560    first character of an anchored pattern as "needed", thus provoking a search
1561    right along the subject, even when the first match of the pattern was going to
1562    fail. The "needed" character is now not set for anchored patterns, unless it
1563    follows something in the pattern that is of non-fixed length. Thus, it still
1564    fulfils its original purpose of finding quick non-matches in cases of nested
1565    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1566    
1567    
1568    Version 4.0 17-Feb-03
1569    ---------------------
1570    
1571    1. If a comment in an extended regex that started immediately after a meta-item
1572    extended to the end of string, PCRE compiled incorrect data. This could lead to
1573    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1574    
1575    2. Moved to autoconf 2.53 and libtool 1.4.2.
1576    
1577    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1578    the special perltest8 script is no longer needed - all the tests can be run
1579    from a single perltest script.
1580    
1581    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1582    by \s. It has now been removed in PCRE. This means it isn't recognized as
1583    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1584    class [:space:] *does* include VT, thereby creating a mess.
1585    
1586    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1587    space and tab.
1588    
1589    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1590    its new features into the main test script, reducing the number of scripts.
1591    
1592    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1593    were backward compatible, and made the (?i) apply to the whole pattern, as if
1594    /i were given. Now it behaves more logically, and applies the option setting
1595    only to what follows. PCRE has been changed to follow suit. However, if it
1596    finds options settings right at the start of the pattern, it extracts them into
1597    the global options, as before. Thus, they show up in the info data.
1598    
1599    8. Added support for the \Q...\E escape sequence. Characters in between are
1600    treated as literals. This is slightly different from Perl in that $ and @ are
1601    also handled as literals inside the quotes. In Perl, they will cause variable
1602    interpolation. Note the following examples:
1603    
1604        Pattern            PCRE matches      Perl matches
1605    
1606        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1607        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1608        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1609    
1610    For compatibility with Perl, \Q...\E sequences are recognized inside character
1611    classes as well as outside them.
1612    
1613    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1614    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1615    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1616    signed/unsigned warnings.
1617    
1618    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1619    option for pcretest, so I've replaced it by a simple function that does just
1620    that job.
1621    
1622    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1623    "pcregrep -".
1624    
1625    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1626    Java package. This provides some syntactic sugar for simple cases of what my
1627    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1628    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1629    item, you can use this simplified notation. Note that only makes sense with
1630    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1631    greediness, whatever the setting of the PCRE_UNGREEDY option.
1632    
1633    13. A change of greediness default within a pattern was not taking effect at
1634    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1635    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1636    was abstracted outside.
1637    
1638    14. PCRE now supports the \G assertion. It is true when the current matching
1639    position is at the start point of the match. This differs from \A when the
1640    starting offset is non-zero. Used with the /g option of pcretest (or similar
1641    code), it works in the same way as it does for Perl's /g option. If all
1642    alternatives of a regex begin with \G, the expression is anchored to the start
1643    match position, and the "anchored" flag is set in the compiled expression.
1644    
1645    15. Some bugs concerning the handling of certain option changes within patterns
1646    have been fixed. These applied to options other than (?ims). For example,
1647    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1648    been the other way round. Some of this was related to change 7 above.
1649    
1650    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1651    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1652    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1653    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1654    
1655    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1656    mode. Unlike ".", it always matches newline, whatever the setting of
1657    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1658    assertions. Perl allows it, but it doesn't (in general) work because it can't
1659    calculate the length of the lookbehind. At least, that's the case for Perl
1660    5.8.0 - I've been told they are going to document that it doesn't work in
1661    future.
1662    
1663    18. Added an error diagnosis for escapes that PCRE does not support: these are
1664    \L, \l, \N, \P, \p, \U, \u, and \X.
1665    
1666    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1667    reading past the end of the pattern in cases such as /[abcd/.
1668    
1669    20. PCRE was getting more memory than necessary for patterns with classes that
1670    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1671    
1672    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1673    compiling PCRE for use with Virtual Pascal.
1674    
1675    22. Small fix to the Makefile to make it work properly if the build is done
1676    outside the source tree.
1677    
1678    23. Added a new extension: a condition to go with recursion. If a conditional
1679    subpattern starts with (?(R) the "true" branch is used if recursion has
1680    happened, whereas the "false" branch is used only at the top level.
1681    
1682    24. When there was a very long string of literal characters (over 255 bytes
1683    without UTF support, over 250 bytes with UTF support), the computation of how
1684    much memory was required could be incorrect, leading to segfaults or other
1685    strange effects.
1686    
1687    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1688    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1689    there was a subsequent back reference to those brackets. This meant that, for
1690    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1691    possible to check for precisely this case. All we can do is abandon the
1692    optimization if .* occurs inside capturing brackets when there are any back
1693    references whatsoever. (See below for a better fix that came later.)
1694    
1695    26. The handling of the optimization for finding the first character of a
1696    non-anchored pattern, and for finding a character that is required later in the
1697    match were failing in some cases. This didn't break the matching; it just
1698    failed to optimize when it could. The way this is done has been re-implemented.
1699    
1700    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1701    
1702    28. Added a new feature that provides some of the functionality that Perl
1703    provides with (?{...}). The facility is termed a "callout". The way it is done
1704    in PCRE is for the caller to provide an optional function, by setting
1705    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1706    global variable. By default it is unset, which disables all calling out. To get
1707    the function called, the regex must include (?C) at appropriate points. This
1708    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1709    This provides a means of identifying different callout points. When PCRE
1710    reaches such a point in the regex, if pcre_callout has been set, the external
1711    function is called. It is provided with data in a structure called
1712    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1713    matching continues; if it returns a non-zero value, the match at the current
1714    point fails. However, backtracking will occur if possible. [This was changed
1715    later and other features added - see item 49 below.]
1716    
1717    29. pcretest is upgraded to test the callout functionality. It provides a
1718    callout function that displays information. By default, it shows the start of
1719    the match and the current position in the text. There are some new data escapes
1720    to vary what happens:
1721    
1722        \C+         in addition, show current contents of captured substrings
1723        \C-         do not supply a callout function
1724        \C!n        return 1 when callout number n is reached
1725        \C!n!m      return 1 when callout number n is reached for the mth time
1726    
1727    30. If pcregrep was called with the -l option and just a single file name, it
1728    output "<stdin>" if a match was found, instead of the file name.
1729    
1730    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1731    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1732    pcre_exec(). This saves a malloc/free per call. The default value of
1733    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1734    when configuring.
1735    
1736    32. The default maximum size of a compiled pattern is 64K. There have been a
1737    few cases of people hitting this limit. The code now uses macros to handle the
1738    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1739    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1740    configuring. Tests 2 and 5 work only with 2-byte links because they output
1741    debugging information about compiled patterns.
1742    
1743    33. Internal code re-arrangements:
1744    
1745    (a) Moved the debugging function for printing out a compiled regex into
1746        its own source file (printint.c) and used #include to pull it into
1747        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1748        separate copies.
1749    
1750    (b) Defined the list of op-code names for debugging as a macro in
1751        internal.h so that it is next to the definition of the opcodes.
1752    
1753    (c) Defined a table of op-code lengths for simpler skipping along compiled
1754        code. This is again a macro in internal.h so that it is next to the
1755        definition of the opcodes.
1756    
1757    34. Added support for recursive calls to individual subpatterns, along the
1758    lines of Robin Houston's patch (but implemented somewhat differently).
1759    
1760    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1761    allow it to read and process whole directories in Win32. This code was
1762    contributed by Lionel Fourquaux; it has not been tested by me.
1763    
1764    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1765    used to name a group. Names consist of alphanumerics and underscores, and must
1766    be unique. Back references use the syntax (?P=name) and recursive calls use
1767    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1768    numbers. The function pcre_fullinfo() can be used after compilation to extract
1769    a name/number map. There are three relevant calls:
1770    
1771      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1772      PCRE_INFO_NAMECOUNT            yields the number of entries
1773      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1774    
1775    The map is a vector of fixed-size entries. The size of each entry depends on
1776    the length of the longest name used. The first two bytes of each entry are the
1777    group number, most significant byte first. There follows the corresponding
1778    name, zero terminated. The names are in alphabetical order.
1779    
1780    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1781    case instead of 255. Making it the same both with and without UTF-8 support
1782    means that the same test output works with both.
1783    
1784    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1785    calling malloc() with a zero argument.
1786    
1787    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1788    optimization. I've improved things by keeping a bitmap of backreferences with
1789    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1790    fact referenced, the optimization can be applied. It is unlikely that a
1791    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1792    the match to follow \n) will appear inside brackets with a number greater than
1793    31, but if it does, any back reference > 31 suppresses the optimization.
1794    
1795    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1796    of disabling numbered capturing parentheses. Any opening parenthesis that is
1797    not followed by ? behaves as if it were followed by ?: but named parentheses
1798    can still be used for capturing (and they will acquire numbers in the usual
1799    way).
1800    
1801    41. Redesigned the return codes from the match() function into yes/no/error so
1802    that errors can be passed back from deep inside the nested calls. A malloc
1803    failure while inside a recursive subpattern call now causes the
1804    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1805    
1806    42. It is now possible to set a limit on the number of times the match()
1807    function is called in a call to pcre_exec(). This facility makes it possible to
1808    limit the amount of recursion and backtracking, though not in a directly
1809    obvious way, because the match() function is used in a number of different
1810    circumstances. The count starts from zero for each position in the subject
1811    string (for non-anchored patterns). The default limit is, for compatibility, a
1812    large number, namely 10 000 000. You can change this in two ways:
1813    
1814    (a) When configuring PCRE before making, you can use --with-match-limit=n
1815        to set a default value for the compiled library.
1816    
1817    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1818        a different value is set. See 45 below.
1819    
1820    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1821    
1822    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1823    of things that can be changed at compile time. The first argument specifies
1824    what is wanted and the second points to where the information is to be placed.
1825    The current list of available information is:
1826    
1827      PCRE_CONFIG_UTF8
1828    
1829    The output is an integer that is set to one if UTF-8 support is available;
1830    otherwise it is set to zero.
1831    
1832      PCRE_CONFIG_NEWLINE
1833    
1834    The output is an integer that it set to the value of the code that is used for
1835    newline. It is either LF (10) or CR (13).
1836    
1837      PCRE_CONFIG_LINK_SIZE
1838    
1839    The output is an integer that contains the number of bytes used for internal
1840    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1841    
1842      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1843    
1844    The output is an integer that contains the threshold above which the POSIX
1845    interface uses malloc() for output vectors. See item 31 above.
1846    
1847      PCRE_CONFIG_MATCH_LIMIT
1848    
1849    The output is an unsigned integer that contains the default limit of the number
1850    of match() calls in a pcre_exec() execution. See 42 above.
1851    
1852    44. pcretest has been upgraded by the addition of the -C option. This causes it
1853    to extract all the available output from the new pcre_config() function, and to
1854    output it. The program then exits immediately.
1855    
1856    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1857    order to support additional features. One way would have been to define
1858    pcre_exec2() (for example) with extra arguments, but this would not have been
1859    extensible, and would also have required all calls to the original function to
1860    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1861    is used for passing in "extra" data from pcre_study().
1862    
1863    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1864    contains the following fields:
1865    
1866      flags         a bitmap indicating which of the following fields are set
1867      study_data    opaque data from pcre_study()
1868      match_limit   a way of specifying a limit on match() calls for a specific
1869                      call to pcre_exec()
1870      callout_data  data for callouts (see 49 below)
1871    
1872    The flag bits are also defined in pcre.h, and are
1873    
1874      PCRE_EXTRA_STUDY_DATA
1875      PCRE_EXTRA_MATCH_LIMIT
1876      PCRE_EXTRA_CALLOUT_DATA
1877    
1878    The pcre_study() function now returns one of these new pcre_extra blocks, with
1879    the actual study data pointed to by the study_data field, and the
1880    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1881    before. That is, this change is entirely upwards-compatible and requires no
1882    change to existing code.
1883    
1884    If you want to pass in additional data to pcre_exec(), you can either place it
1885    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1886    block.
1887    
1888    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1889    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1890    times with different match limits, until it finds the minimum value needed for
1891    pcre_exec() to complete. The value is then output. This can be instructive; for
1892    most simple matches the number is quite small, but for pathological cases it
1893    gets very large very quickly.
1894    
1895    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1896    returns the size of the data block pointed to by the study_data field in a
1897    pcre_extra block, that is, the value that was passed as the argument to
1898    pcre_malloc() when PCRE was getting memory in which to place the information
1899    created by pcre_study(). The fourth argument should point to a size_t variable.
1900    pcretest has been extended so that this information is shown after a successful
1901    pcre_study() call when information about the compiled regex is being displayed.
1902    
1903    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1904    because what follows is always an absolute path. (Later: it turns out that this
1905    is more than cosmetic for MinGW, because it doesn't like empty path
1906    components.)
1907    
1908    49. Some changes have been made to the callout feature (see 28 above):
1909    
1910    (i)  A callout function now has three choices for what it returns:
1911    
1912           0  =>  success, carry on matching
1913         > 0  =>  failure at this point, but backtrack if possible
1914         < 0  =>  serious error, return this value from pcre_exec()
1915    
1916         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1917         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1918         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1919         use by callout functions. It will never be used by PCRE itself.
1920    
1921    (ii) The pcre_extra structure (see 45 above) has a void * field called
1922         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1923         pcre_callout_block structure has a field of the same name. The contents of
1924         the field passed in the pcre_extra structure are passed to the callout
1925         function in the corresponding field in the callout block. This makes it
1926         easier to use the same callout-containing regex from multiple threads. For
1927         testing, the pcretest program has a new data escape
1928    
1929           \C*n        pass the number n (may be negative) as callout_data
1930    
1931         If the callout function in pcretest receives a non-zero value as
1932         callout_data, it returns that value.
1933    
1934    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1935    there were some redundant $(CFLAGS) in commands that are now specified as
1936    $(LINK), which already includes $(CFLAGS).
1937    
1938    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1939    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1940    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1941    one-byte characters throughout. Note that case-insensitive matching applies
1942    only to characters whose values are less than 256. PCRE doesn't support the
1943    notion of cases for higher-valued characters.
1944    
1945    (i)   A character class whose characters are all within 0-255 is handled as
1946          a bit map, and the map is inverted for negative classes. Previously, a
1947          character > 255 always failed to match such a class; however it should
1948          match if the class was a negative one (e.g. [^ab]). This has been fixed.
1949    
1950    (ii)  A negated character class with a single character < 255 is coded as
1951          "not this character" (OP_NOT). This wasn't working properly when the test
1952          character was multibyte, either singly or repeated.
1953    
1954    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1955          mode, for example: \x{100}{2,3}.
1956    
1957    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1958          singly or repeated) now correctly test multibyte characters. However,
1959          PCRE doesn't recognize any characters with values greater than 255 as
1960          digits, spaces, or word characters. Such characters always match \D, \S,
1961          and \W, and never match \d, \s, or \w.
1962    
1963    (v)   Classes may now contain characters and character ranges with values
1964          greater than 255. For example: [ab\x{100}-\x{400}].
1965    
1966    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
1967          PCRE in UTF-8 mode.
1968    
1969    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1970    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1971    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1972    value.)
1973    
1974    53. The single man page has become too large. I have therefore split it up into
1975    a number of separate man pages. These also give rise to individual HTML pages;
1976    these are now put in a separate directory, and there is an index.html page that
1977    lists them all. Some hyperlinking between the pages has been installed.
1978    
1979    54. Added convenience functions for handling named capturing parentheses.
1980    
1981    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1982    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1983    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1984    are faulted.
1985    
1986    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1987    calling configure. These values are used when compiling the dftables.c program
1988    which is run to generate the source of the default character tables. They
1989    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1990    you will need to set these values.
1991    
1992    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1993    
1994    
1995    Version 3.9 02-Jan-02
1996    ---------------------
1997    
1998    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1999    
2000    2. If --disable-static was given, the building process failed when trying to
2001    build pcretest and pcregrep. (For some reason it was using libtool to compile
2002    them, which is not right, as they aren't part of the library.)
2003    
2004    
2005    Version 3.8 18-Dec-01
2006    ---------------------
2007    
2008    1. The experimental UTF-8 code was completely screwed up. It was packing the
2009    bytes in the wrong order. How dumb can you get?
2010    
2011    
2012    Version 3.7 29-Oct-01
2013    ---------------------
2014    
2015    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2016    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2017    this didn't happen under Solaris 8, where I normally test things.
2018    
2019    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2020    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2021    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2022    this fix an hour or so after the initial 3.7 release.)
2023    
2024    
2025    Version 3.6 23-Oct-01
2026    ---------------------
2027    
2028    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2029    offsets passed as NULL with zero offset count.
2030    
2031    2. The config.guess and config.sub files had not been updated when I moved to
2032    the latest autoconf.
2033    
2034    
2035    Version 3.5 15-Aug-01
2036    ---------------------
2037    
2038    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2039    had been forgotten.
2040    
2041    2. By using declared but undefined structures, we can avoid using "void"
2042    definitions in pcre.h while keeping the internal definitions of the structures
2043    private.
2044    
2045    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2046    user point of view, this means that both static and shared libraries are built
2047    by default, but this can be individually controlled. More of the work of
2048    handling this static/shared cases is now inside libtool instead of PCRE's make
2049    file.
2050    
2051    4. The pcretest utility is now installed along with pcregrep because it is
2052    useful for users (to test regexs) and by doing this, it automatically gets
2053    relinked by libtool. The documentation has been turned into a man page, so
2054    there are now .1, .txt, and .html versions in /doc.
2055    
2056    5. Upgrades to pcregrep:
2057       (i)   Added long-form option names like gnu grep.
2058       (ii)  Added --help to list all options with an explanatory phrase.
2059       (iii) Added -r, --recursive to recurse into sub-directories.
2060       (iv)  Added -f, --file to read patterns from a file.
2061    
2062    6. pcre_exec() was referring to its "code" argument before testing that
2063    argument for NULL (and giving an error if it was NULL).
2064    
2065    7. Upgraded Makefile.in to allow for compiling in a different directory from
2066    the source directory.
2067    
2068    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2069    options bits, the pointer it was passed was to an int instead of to an unsigned
2070    long int. This mattered only on 64-bit systems.
2071    
2072    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2073    generated) instead of pcre.in, which it its source. Also made the same change
2074    in several of the .c files.
2075    
2076    10. A new release of gcc defines printf() as a macro, which broke pcretest
2077    because it had an ifdef in the middle of a string argument for printf(). Fixed
2078    by using separate calls to printf().
2079    
2080    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2081    script, to force use of CR or LF instead of \n in the source. On non-Unix
2082    systems, the value can be set in config.h.
2083    
2084    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2085    absolute limit. Changed the text of the error message to make this clear, and
2086    likewise updated the man page.
2087    
2088    13. The limit of 99 on the number of capturing subpatterns has been removed.
2089    The new limit is 65535, which I hope will not be a "real" limit.
2090    
2091    
2092    Version 3.4 22-Aug-00
2093    ---------------------
2094    
2095    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2096    
2097    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2098    
2099    
2100    Version 3.3 01-Aug-00
2101    ---------------------
2102    
2103    1. If an octal character was given, but the value was greater than \377, it
2104    was not getting masked to the least significant bits, as documented. This could
2105    lead to crashes in some systems.
2106    
2107    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2108    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2109    
2110    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2111    These just pass their arguments on to (pcre_free)(), but they are provided
2112    because some uses of PCRE bind it to non-C systems that can call its functions,
2113    but cannot call free() or pcre_free() directly.
2114    
2115    4. Add "make test" as a synonym for "make check". Corrected some comments in
2116    the Makefile.
2117    
2118    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2119    Makefile.
2120    
2121    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2122    command called pgrep for grepping around the active processes.
2123    
2124    7. Added the beginnings of support for UTF-8 character strings.
2125    
2126    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2127    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2128    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2129    out for the ar command.)
2130    
2131    
2132    Version 3.2 12-May-00
2133    ---------------------
2134    
2135    This is purely a bug fixing release.
2136    
2137    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2138    of ZA. This was just one example of several cases that could provoke this bug,
2139    which was introduced by change 9 of version 2.00. The code for breaking
2140    infinite loops after an iteration that matches an empty string was't working
2141    correctly.
2142    
2143    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2144    when matched against abbab (for example). After matching an empty string, it
2145    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2146    caused it to match further down the string than it should.
2147    
2148    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2149    was there because it doesn't seem to be needed, and it causes trouble on some
2150    systems, as it is not a Standard C header. It has been removed.
2151    
2152    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2153    were reported on the Macintosh. The changes were from
2154    
2155      while ((c = *(++ptr)) != 0 && c != '\n');
2156    to
2157      while ((c = *(++ptr)) != 0 && c != '\n') ;
2158    
2159    Totally extraordinary, but if that's what it takes...
2160    
2161    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2162    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2163    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2164    assumes the way PCRE uses memmove() (always moving upwards).
2165    
2166    6. PCRE is being used in one environment where strchr() is not available. There
2167    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2168    faster code anyway.
2169    
2170    
2171    Version 3.1 09-Feb-00
2172    ---------------------
2173    
2174    The only change in this release is the fixing of some bugs in Makefile.in for
2175    the "install" target:
2176    
2177    (1) It was failing to install pcreposix.h.
2178    
2179    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2180    
2181    
2182    Version 3.0 01-Feb-00
2183    ---------------------
2184    
2185    1. Add support for the /+ modifier to perltest (to output $` like it does in
2186    pcretest).
2187    
2188    2. Add support for the /g modifier to perltest.
2189    
2190    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2191    matches null strings.
2192    
2193    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2194    pattern. Perl treats empty patterns specially - it reuses the most recent
2195    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2196    effect.
2197    
2198    5. The POSIX interface was broken in that it was just handing over the POSIX
2199    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2200    required a bigger vector, with some working space on the end. This means that
2201    the POSIX wrapper now has to get and free some memory, and copy the results.
2202    
2203    6. Added some simple autoconf support, placing the test data and the
2204    documentation in separate directories, re-organizing some of the
2205    information files, and making it build pcre-config (a GNU standard). Also added
2206    libtool support for building PCRE as a shared library, which is now the
2207    default.
2208    
2209    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2210    09 are not valid octal constants. Single digits will be used for minor values
2211    less than 10.
2212    
2213    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2214    existing programs that set these in the POSIX interface can use PCRE without
2215    modification.
2216    
2217    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2218    return all that pcre_info() returns, plus additional data. The pcre_info()
2219    function is retained for compatibility, but is considered to be obsolete.
2220    
2221    10. Added experimental recursion feature (?R) to handle one common case that
2222    Perl 5.6 will be able to do with (?p{...}).
2223    
2224    11. Added support for POSIX character classes like [:alpha:], which Perl is
2225    adopting.
2226    
2227    
2228    Version 2.08 31-Aug-99
2229    ----------------------
2230    
2231    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2232    trying to match at the startoffset position, but instead was moving forward to
2233    the next newline as if a previous match had failed.
2234    
2235    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2236    and could get into a loop if a null string was matched other than at the start
2237    of the subject.
2238    
2239    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2240    be distinguished at compile time, and for completeness also added PCRE_DATE.
2241    
2242    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2243    in GnuWin32 environments.
2244    
2245    
2246    Version 2.07 29-Jul-99
2247    ----------------------
2248    
2249    1. The documentation is now supplied in plain text form and HTML as well as in
2250    the form of man page sources.
2251    
2252    2. C++ compilers don't like assigning (void *) values to other pointer types.
2253    In particular this affects malloc(). Although there is no problem in Standard
2254    C, I've put in casts to keep C++ compilers happy.
2255    
2256    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2257    should be (const char *).
2258    
2259    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2260    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2261    However, I haven't made this a standard facility. The documentation doesn't
2262    mention it, and the Makefile doesn't support it.
2263    
2264    5. The Makefile now contains an "install" target, with editable destinations at
2265    the top of the file. The pcretest program is not installed.
2266    
2267    6. pgrep -V now gives the PCRE version number and date.
2268    
2269    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2270    causing the entire string to be ignored, instead of just the last character.
2271    
2272    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2273    non-matching string, it can take a very, very long time, even for strings of
2274    quite modest length, because of the nested recursion. PCRE now does better in
2275    some of these cases. It does this by remembering the last required literal
2276    character in the pattern, and pre-searching the subject to ensure it is present
2277    before running the real match. In other words, it applies a heuristic to detect
2278    some types of certain failure quickly, and in the above example, if presented
2279    with a string that has no trailing " it gives "no match" very quickly.
2280    
2281    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2282    other alternatives are tried instead.
2283    
2284    
2285    Version 2.06 09-Jun-99
2286    ----------------------
2287    
2288    1. Change pcretest's output for amount of store used to show just the code
2289    space, because the remainder (the data block) varies in size between 32-bit and
2290    64-bit systems.
2291    
2292    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2293    start matching at. This allows lookbehinds to work when searching for multiple
2294    occurrences in a string.
2295    
2296    3. Added additional options to pcretest for testing multiple occurrences:
2297    
2298       /+   outputs the rest of the string that follows a match
2299       /g   loops for multiple occurrences, using the new startoffset argument
2300       /G   loops for multiple occurrences by passing an incremented pointer
2301    
2302    4. PCRE wasn't doing the "first character" optimization for patterns starting
2303    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2304    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2305    the letter 'x'. On long subject strings, this gives a significant speed-up.
2306    
2307    
2308    Version 2.05 21-Apr-99
2309    ----------------------
2310    
2311    1. Changed the type of magic_number from int to long int so that it works
2312    properly on 16-bit systems.
2313    
2314    2. Fixed a bug which caused patterns starting with .* not to work correctly
2315    when the subject string contained newline characters. PCRE was assuming
2316    anchoring for such patterns in all cases, which is not correct because .* will
2317    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2318    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2319    must be retried after every newline in the subject.
2320    
2321    
2322    Version 2.04 18-Feb-99
2323    ----------------------
2324    
2325    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2326    computation of the store needed to hold the pattern was incorrect (too large).
2327    If such patterns were nested a few deep, this could multiply and become a real
2328    problem.
2329    
2330    2. Added /M option to pcretest to show the memory requirement of a specific
2331    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2332    
2333    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2334    compiled in such a way that the backtracking after subsequent failure was
2335    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2336    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2337    
2338    
2339    Version 2.03 02-Feb-99
2340    ----------------------
2341    
2342    1. Fixed typo and small mistake in man page.
2343    
2344    2. Added 4th condition (GPL supersedes if conflict) and created separate
2345    LICENCE file containing the conditions.
2346    
2347    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2348    Perl, that is the internal \ allows the delimiter to be included in the
2349    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2350    the final delimiter, add \ to the end of the pattern (to test the error).
2351    
2352    4. Added the convenience functions for extracting substrings after a successful
2353    match. Updated pcretest to make it able to test these functions.
2354    
2355    
2356    Version 2.02 14-Jan-99
2357    ----------------------
2358    
2359    1. Initialized the working variables associated with each extraction so that
2360    their saving and restoring doesn't refer to uninitialized store.
2361    
2362    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2363    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2364    fix the problem.
2365    
2366    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2367    calls, and wasn't printing the correct value for compiling calls. Increased the
2368    default value of LOOPREPEAT, and the number of significant figures in the
2369    times.
2370    
2371    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2372    
2373    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2374    a building problem on Windows NT with a FAT file system.
2375    
2376    
2377    Version 2.01 21-Oct-98
2378    ----------------------
2379    
2380    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2381    to character tables built by pcre_maketables() in the current locale. If NULL
2382    is passed, the default tables are used.
2383    
2384    
2385    Version 2.00 24-Sep-98
2386    ----------------------
2387    
2388    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2389    it any more.
2390    
2391    2. Allow quantification of (?>) groups, and make it work correctly.
2392    
2393    3. The first character computation wasn't working for (?>) groups.
2394    
2395    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2396    end of the subject) and add 5.005's \z, which really does match only at the
2397    very end of the subject.
2398    
2399    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2400    
2401    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2402    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2403    localized options. All options to pcre_study() were also removed.
2404    
2405    7. Add other new features from 5.005:
2406    
2407       $(?<=           positive lookbehind
2408       $(?<!           negative lookbehind
2409       (?imsx-imsx)    added the unsetting capability
2410                       such a setting is global if at outer level; local otherwise
2411       (?imsx-imsx:)   non-capturing groups with option setting
2412       (?(cond)re|re)  conditional pattern matching
2413    
2414       A backreference to itself in a repeated group matches the previous
2415       captured string.
2416    
2417    8. General tidying up of studying (both automatic and via "study")
2418    consequential on the addition of new assertions.
2419    
2420    9. As in 5.005, unlimited repeated groups that could match an empty substring
2421    are no longer faulted at compile time. Instead, the loop is forcibly broken at
2422    runtime if any iteration does actually match an empty substring.
2423    
2424    10. Include the RunTest script in the distribution.
2425    
2426    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2427    discrepancies, some of which were old and were also with respect to 5.004. They
2428    have now been fixed.
2429    
2430    
2431    Version 1.09 28-Apr-98
2432  ----------------------  ----------------------
2433    
2434  1. A negated single character class followed by a quantifier with a minimum  1. A negated single character class followed by a quantifier with a minimum

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