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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.1 05-Mar-07
5    ---------------------
6    
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
11    
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
18    
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The maintain/132html script that I use to
25        generate HTML has been updated to handle .nf/.fi and to complain if it
26        encounters .br or .in.
27    
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, for the benefit
30        of those who have to compile without Autotools (compare pcre.h).
31    
32     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
33        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
34        makevp.bat for the current PCRE, using the additional files !compile.txt,
35        !linklib.txt, and pcregexp.pas.
36    
37     6. A Windows user reported a minor discrepancy with test 2, which turned out
38        to be caused by a trailing space on an input line that had got lost in his
39        copy. The trailing space was an accident, so I've just removed it.
40    
41     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
42        that is needed.
43    
44     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
45        as "const" (a) because they are and (b) because it helps the PHP
46        maintainers who have recently made a script to detect big data structures
47        in the php code that should be moved to the .rodata section. I remembered
48        to update Builducptable as well, so it won't revert if ucptable.h is ever
49        re-created.
50    
51     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
52        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
53        order to be able to cut out the UTF-8 tables in the latter when UTF-8
54        support is not required. This saves 1.5-2K of code, which is important in
55        some applications.
56    
57    10. The emulated memmove() function in pcre_internal.h (provided for those
58        environments that have neither memmove() nor bcopy()) was defining its
59        arguments as char * instead of void *.
60    
61    
62    Version 7.0 19-Dec-06
63    ---------------------
64    
65     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
66        moving to gcc 4.1.1.
67    
68     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
69        sys/time.h, which is documented as needed for this function. It doesn't
70        seem to matter on Linux, but it showed up on some releases of OS X.
71    
72     3. It seems that there are systems where bytes whose values are greater than
73        127 match isprint() in the "C" locale. The "C" locale should be the
74        default when a C program starts up. In most systems, only ASCII printing
75        characters match isprint(). This difference caused the output from pcretest
76        to vary, making some of the tests fail. I have changed pcretest so that:
77    
78        (a) When it is outputting text in the compiled version of a pattern, bytes
79            other than 32-126 are always shown as hex escapes.
80    
81        (b) When it is outputting text that is a matched part of a subject string,
82            it does the same, unless a different locale has been set for the match
83            (using the /L modifier). In this case, it uses isprint() to decide.
84    
85     4. Fixed a major bug that caused incorrect computation of the amount of memory
86        required for a compiled pattern when options that changed within the
87        pattern affected the logic of the preliminary scan that determines the
88        length. The relevant options are -x, and -i in UTF-8 mode. The result was
89        that the computed length was too small. The symptoms of this bug were
90        either the PCRE error "internal error: code overflow" from pcre_compile(),
91        or a glibc crash with a message such as "pcretest: free(): invalid next
92        size (fast)". Examples of patterns that provoked this bug (shown in
93        pcretest format) are:
94    
95          /(?-x: )/x
96          /(?x)(?-x: \s*#\s*)/
97          /((?i)[\x{c0}])/8
98          /(?i:[\x{c0}])/8
99    
100        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
101        is now done differently.
102    
103     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
104        wrapper classes; (b) implement a new function in the C++ scanner that is
105        more efficient than the old way of doing things because it avoids levels of
106        recursion in the regex matching; (c) add a paragraph to the documentation
107        for the FullMatch() function.
108    
109     6. The escape sequence \n was being treated as whatever was defined as
110        "newline". Not only was this contrary to the documentation, which states
111        that \n is character 10 (hex 0A), but it also went horribly wrong when
112        "newline" was defined as CRLF. This has been fixed.
113    
114     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
115        was being set to -1 for the "end of line" case (supposedly a value that no
116        character can have). Though this value is never used (the check for end of
117        line is "zero bytes in current character"), it caused compiler complaints.
118        I've changed it to 0xffffffff.
119    
120     8. In pcre_version.c, the version string was being built by a sequence of
121        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
122        string (as it is for production releases) called a macro with an empty
123        argument. The C standard says the result of this is undefined. The gcc
124        compiler treats it as an empty string (which was what was wanted) but it is
125        reported that Visual C gives an error. The source has been hacked around to
126        avoid this problem.
127    
128     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
129        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
130        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
131        of them did).
132    
133    10. Originally, pcretest opened its input and output without "b"; then I was
134        told that "b" was needed in some environments, so it was added for release
135        5.0 to both the input and output. (It makes no difference on Unix-like
136        systems.) Later I was told that it is wrong for the input on Windows. I've
137        now abstracted the modes into two macros, to make it easier to fiddle with
138        them, and removed "b" from the input mode under Windows.
139    
140    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
141    
142    12. Added -help and --help to pcretest as an official way of being reminded
143        of the options.
144    
145    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
146        and pcrecpp.cc because they annoy compilers at high warning levels.
147    
148    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
149    
150    15. Fixed an occurrence of == in configure.ac that should have been = (shell
151        scripts are not C programs :-) and which was not noticed because it works
152        on Linux.
153    
154    16. pcretest is supposed to handle any length of pattern and data line (as one
155        line or as a continued sequence of lines) by extending its input buffer if
156        necessary. This feature was broken for very long pattern lines, leading to
157        a string of junk being passed to pcre_compile() if the pattern was longer
158        than about 50K.
159    
160    17. I have done a major re-factoring of the way pcre_compile() computes the
161        amount of memory needed for a compiled pattern. Previously, there was code
162        that made a preliminary scan of the pattern in order to do this. That was
163        OK when PCRE was new, but as the facilities have expanded, it has become
164        harder and harder to keep it in step with the real compile phase, and there
165        have been a number of bugs (see for example, 4 above). I have now found a
166        cunning way of running the real compile function in a "fake" mode that
167        enables it to compute how much memory it would need, while actually only
168        ever using a few hundred bytes of working memory and without too many
169        tests of the mode. This should make future maintenance and development
170        easier. A side effect of this work is that the limit of 200 on the nesting
171        depth of parentheses has been removed (though this was never a serious
172        limitation, I suspect). However, there is a downside: pcre_compile() now
173        runs more slowly than before (30% or more, depending on the pattern). I
174        hope this isn't a big issue. There is no effect on runtime performance.
175    
176    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
177        newline (only possible for the last line of a file) and it was a
178        pattern that set a locale (followed by /Lsomething), pcretest crashed.
179    
180    19. Added additional timing features to pcretest. (1) The -tm option now times
181        matching only, not compiling. (2) Both -t and -tm can be followed, as a
182        separate command line item, by a number that specifies the number of
183        repeats to use when timing. The default is 50000; this gives better
184        precision, but takes uncomfortably long for very large patterns.
185    
186    20. Extended pcre_study() to be more clever in cases where a branch of a
187        subpattern has no definite first character. For example, (a*|b*)[cd] would
188        previously give no result from pcre_study(). Now it recognizes that the
189        first character must be a, b, c, or d.
190    
191    21. There was an incorrect error "recursive call could loop indefinitely" if
192        a subpattern (or the entire pattern) that was being tested for matching an
193        empty string contained only one non-empty item after a nested subpattern.
194        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
195        incorrectly, because the \d was being skipped in the check.
196    
197    22. The pcretest program now has a new pattern option /B and a command line
198        option -b, which is equivalent to adding /B to every pattern. This causes
199        it to show the compiled bytecode, without the additional information that
200        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
201        is the same as /B/I).
202    
203    23. A new optimization is now able automatically to treat some sequences such
204        as a*b as a*+b. More specifically, if something simple (such as a character
205        or a simple class like \d) has an unlimited quantifier, and is followed by
206        something that cannot possibly match the quantified thing, the quantifier
207        is automatically "possessified".
208    
209    24. A recursive reference to a subpattern whose number was greater than 39
210        went wrong under certain circumstances in UTF-8 mode. This bug could also
211        have affected the operation of pcre_study().
212    
213    25. Realized that a little bit of performance could be had by replacing
214        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
215    
216    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
217    
218    27. Possessive quantifiers such as a++ were previously implemented by turning
219        them into atomic groups such as ($>a+). Now they have their own opcodes,
220        which improves performance. This includes the automatically created ones
221        from 23 above.
222    
223    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
224        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
225        the first matched character to be a colon. This applied both to named and
226        numbered groups.
227    
228    29. The ucpinternal.h header file was missing its idempotency #ifdef.
229    
230    30. I was sent a "project" file called libpcre.a.dev which I understand makes
231        building PCRE on Windows easier, so I have included it in the distribution.
232    
233    31. There is now a check in pcretest against a ridiculously large number being
234        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
235        loop, the loop is abandoned.
236    
237    32. Forward references to subpatterns in conditions such as (?(2)...) where
238        subpattern 2 is defined later cause pcre_compile() to search forwards in
239        the pattern for the relevant set of parentheses. This search went wrong
240        when there were unescaped parentheses in a character class, parentheses
241        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
242    
243    33. "Subroutine" calls and backreferences were previously restricted to
244        referencing subpatterns earlier in the regex. This restriction has now
245        been removed.
246    
247    34. Added a number of extra features that are going to be in Perl 5.10. On the
248        whole, these are just syntactic alternatives for features that PCRE had
249        previously implemented using the Python syntax or my own invention. The
250        other formats are all retained for compatibility.
251    
252        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
253            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
254            also .NET compatible.
255    
256        (b) A recursion or subroutine call to a named group can now be defined as
257            (?&name) as well as (?P>name).
258    
259        (c) A backreference to a named group can now be defined as \k<name> or
260            \k'name' as well as (?P=name). The new forms, as well as being in Perl
261            5.10, are also .NET compatible.
262    
263        (d) A conditional reference to a named group can now use the syntax
264            (?(<name>) or (?('name') as well as (?(name).
265    
266        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
267            groups (named and numbered) that are never evaluated inline, but can be
268            called as "subroutines" from elsewhere. In effect, the DEFINE condition
269            is always false. There may be only one alternative in such a group.
270    
271        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
272            as the simple (?(R). The condition is true only if the most recent
273            recursion is that of the given number or name. It does not search out
274            through the entire recursion stack.
275    
276        (g) The escape \gN or \g{N} has been added, where N is a positive or
277            negative number, specifying an absolute or relative reference.
278    
279    35. Tidied to get rid of some further signed/unsigned compiler warnings and
280        some "unreachable code" warnings.
281    
282    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
283        things, this adds five new scripts.
284    
285    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
286        There were also incompatibilities regarding the handling of \Q..\E inside
287        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
288        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
289    
290    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
291        matches an empty string, and forcibly breaks the loop. There were bugs in
292        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
293        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
294        separate and independent bugs (that affected different cases) have been
295        fixed.
296    
297    39. Refactored the code to abolish the use of different opcodes for small
298        capturing bracket numbers. This is a tidy that I avoided doing when I
299        removed the limit on the number of capturing brackets for 3.5 back in 2001.
300        The new approach is not only tidier, it makes it possible to reduce the
301        memory needed to fix the previous bug (38).
302    
303    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
304        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
305        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
306        mode.
307    
308    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
309        report.
310    
311    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
312        copy construction and assignment in the C++ wrapper.
313    
314    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
315        couple of bugs that could have given wrong results in the "--newline=crlf"
316        case.
317    
318    44. Added a number of casts and did some reorganization of signed/unsigned int
319        variables following suggestions from Dair Grant. Also renamed the variable
320        "this" as "item" because it is a C++ keyword.
321    
322    45. Arranged for dftables to add
323    
324          #include "pcre_internal.h"
325    
326        to pcre_chartables.c because without it, gcc 4.x may remove the array
327        definition from the final binary if PCRE is built into a static library and
328        dead code stripping is activated.
329    
330    46. For an unanchored pattern, if a match attempt fails at the start of a
331        newline sequence, and the newline setting is CRLF or ANY, and the next two
332        characters are CRLF, advance by two characters instead of one.
333    
334    
335    Version 6.7 04-Jul-06
336    ---------------------
337    
338     1. In order to handle tests when input lines are enormously long, pcretest has
339        been re-factored so that it automatically extends its buffers when
340        necessary. The code is crude, but this _is_ just a test program. The
341        default size has been increased from 32K to 50K.
342    
343     2. The code in pcre_study() was using the value of the re argument before
344        testing it for NULL. (Of course, in any sensible call of the function, it
345        won't be NULL.)
346    
347     3. The memmove() emulation function in pcre_internal.h, which is used on
348        systems that lack both memmove() and bcopy() - that is, hardly ever -
349        was missing a "static" storage class specifier.
350    
351     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
352        containing an extended class (one that cannot be represented by a bitmap
353        because it contains high-valued characters or Unicode property items, e.g.
354        [\pZ]). Almost always one would set UTF-8 mode when processing such a
355        pattern, but PCRE should not loop if you do not (it no longer does).
356        [Detail: two cases were found: (a) a repeated subpattern containing an
357        extended class; (b) a recursive reference to a subpattern that followed a
358        previous extended class. It wasn't skipping over the extended class
359        correctly when UTF-8 mode was not set.]
360    
361     5. A negated single-character class was not being recognized as fixed-length
362        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
363        compile error "lookbehind assertion is not fixed length".
364    
365     6. The RunPerlTest auxiliary script was showing an unexpected difference
366        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
367        write a Perl script that can interpret lines of an input file either as
368        byte characters or as UTF-8, which is what "perltest" was being required to
369        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
370        can't do is switch easily at run time between having the "use utf8;" pragma
371        or not. In the end, I fudged it by using the RunPerlTest script to insert
372        "use utf8;" explicitly for the UTF-8 tests.
373    
374     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
375        the end of the subject string, contrary to the documentation and to what
376        Perl does. This was true of both matching functions. Now it matches only at
377        the start of the subject and immediately after *internal* newlines.
378    
379     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
380        a pointer to an int instead of a pointer to an unsigned long int. This
381        caused problems on 64-bit systems.
382    
383     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
384        instance of the 'standard' template library not being so standard".
385    
386    10. There was no check on the number of named subpatterns nor the maximum
387        length of a subpattern name. The product of these values is used to compute
388        the size of the memory block for a compiled pattern. By supplying a very
389        long subpattern name and a large number of named subpatterns, the size
390        computation could be caused to overflow. This is now prevented by limiting
391        the length of names to 32 characters, and the number of named subpatterns
392        to 10,000.
393    
394    11. Subpatterns that are repeated with specific counts have to be replicated in
395        the compiled pattern. The size of memory for this was computed from the
396        length of the subpattern and the repeat count. The latter is limited to
397        65535, but there was no limit on the former, meaning that integer overflow
398        could in principle occur. The compiled length of a repeated subpattern is
399        now limited to 30,000 bytes in order to prevent this.
400    
401    12. Added the optional facility to have named substrings with the same name.
402    
403    13. Added the ability to use a named substring as a condition, using the
404        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
405        are numbers (not recommended). Forward references are permitted.
406    
407    14. Added forward references in named backreferences (if you see what I mean).
408    
409    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
410        pattern could run off the end of the subject. For example, the pattern
411        "(?s)(.{1,5})"8 did this with the subject "ab".
412    
413    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
414        PCRE_CASELESS was set when matching characters that were quantified with ?
415        or *.
416    
417    17. A character class other than a single negated character that had a minimum
418        but no maximum quantifier - for example [ab]{6,} - was not handled
419        correctly by pce_dfa_exec(). It would match only one character.
420    
421    18. A valid (though odd) pattern that looked like a POSIX character
422        class but used an invalid character after [ (for example [[,abc,]]) caused
423        pcre_compile() to give the error "Failed: internal error: code overflow" or
424        in some cases to crash with a glibc free() error. This could even happen if
425        the pattern terminated after [[ but there just happened to be a sequence of
426        letters, a binary zero, and a closing ] in the memory that followed.
427    
428    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
429        over the years. Originally (before any Unicode support), just the bottom 8
430        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
431        output from "man perlunicode" includes this:
432    
433          The regular expression compiler produces polymorphic opcodes.  That
434          is, the pattern adapts to the data and automatically switches to
435          the Unicode character scheme when presented with Unicode data--or
436          instead uses a traditional byte scheme when presented with byte
437          data.
438    
439        Sadly, a wide octal escape does not cause a switch, and in a string with
440        no other multibyte characters, these octal escapes are treated as before.
441        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
442        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
443        Unicode string.
444    
445        I have not perpetrated such confusion in PCRE. Up till now, it took just
446        the bottom 8 bits, as in old Perl. I have now made octal escapes with
447        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
448        translate to the appropriate multibyte character.
449    
450    29. Applied some refactoring to reduce the number of warnings from Microsoft
451        and Borland compilers. This has included removing the fudge introduced
452        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
453        a warning about an unused variable.
454    
455    21. PCRE has not included VT (character 0x0b) in the set of whitespace
456        characters since release 4.0, because Perl (from release 5.004) does not.
457        [Or at least, is documented not to: some releases seem to be in conflict
458        with the documentation.] However, when a pattern was studied with
459        pcre_study() and all its branches started with \s, PCRE still included VT
460        as a possible starting character. Of course, this did no harm; it just
461        caused an unnecessary match attempt.
462    
463    22. Removed a now-redundant internal flag bit that recorded the fact that case
464        dependency changed within the pattern. This was once needed for "required
465        byte" processing, but is no longer used. This recovers a now-scarce options
466        bit. Also moved the least significant internal flag bit to the most-
467        significant bit of the word, which was not previously used (hangover from
468        the days when it was an int rather than a uint) to free up another bit for
469        the future.
470    
471    23. Added support for CRLF line endings as well as CR and LF. As well as the
472        default being selectable at build time, it can now be changed at runtime
473        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
474        specify that it is scanning data with non-default line endings.
475    
476    24. Changed the definition of CXXLINK to make it agree with the definition of
477        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
478    
479    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
480        recursions. This makes a big different to stack usage for some patterns.
481    
482    26. If a subpattern containing a named recursion or subroutine reference such
483        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
484        the space required for the compiled pattern went wrong and gave too small a
485        value. Depending on the environment, this could lead to "Failed: internal
486        error: code overflow at offset 49" or "glibc detected double free or
487        corruption" errors.
488    
489    27. Applied patches from Google (a) to support the new newline modes and (b) to
490        advance over multibyte UTF-8 characters in GlobalReplace.
491    
492    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
493        difference for some implementation of PCRE in some Windows version.
494    
495    29. Added some extra testing facilities to pcretest:
496    
497        \q<number>   in a data line sets the "match limit" value
498        \Q<number>   in a data line sets the "match recursion limt" value
499        -S <number>  sets the stack size, where <number> is in megabytes
500    
501        The -S option isn't available for Windows.
502    
503    
504    Version 6.6 06-Feb-06
505    ---------------------
506    
507     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
508        in pcreposix.h. I have copied the definition from pcre.h.
509    
510     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
511        because pcre.h is no longer a built file.
512    
513     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
514        not normally included in the compiled code.
515    
516    
517    Version 6.5 01-Feb-06
518    ---------------------
519    
520     1. When using the partial match feature with pcre_dfa_exec(), it was not
521        anchoring the second and subsequent partial matches at the new starting
522        point. This could lead to incorrect results. For example, with the pattern
523        /1234/, partially matching against "123" and then "a4" gave a match.
524    
525     2. Changes to pcregrep:
526    
527        (a) All non-match returns from pcre_exec() were being treated as failures
528            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
529            error message is output. Some extra information is given for the
530            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
531            probably the only errors that are likely to be caused by users (by
532            specifying a regex that has nested indefinite repeats, for instance).
533            If there are more than 20 of these errors, pcregrep is abandoned.
534    
535        (b) A binary zero was treated as data while matching, but terminated the
536            output line if it was written out. This has been fixed: binary zeroes
537            are now no different to any other data bytes.
538    
539        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
540            used to set a locale for matching. The --locale=xxxx long option has
541            been added (no short equivalent) to specify a locale explicitly on the
542            pcregrep command, overriding the environment variables.
543    
544        (d) When -B was used with -n, some line numbers in the output were one less
545            than they should have been.
546    
547        (e) Added the -o (--only-matching) option.
548    
549        (f) If -A or -C was used with -c (count only), some lines of context were
550            accidentally printed for the final match.
551    
552        (g) Added the -H (--with-filename) option.
553    
554        (h) The combination of options -rh failed to suppress file names for files
555            that were found from directory arguments.
556    
557        (i) Added the -D (--devices) and -d (--directories) options.
558    
559        (j) Added the -F (--fixed-strings) option.
560    
561        (k) Allow "-" to be used as a file name for -f as well as for a data file.
562    
563        (l) Added the --colo(u)r option.
564    
565        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
566            is not present by default.
567    
568     3. A nasty bug was discovered in the handling of recursive patterns, that is,
569        items such as (?R) or (?1), when the recursion could match a number of
570        alternatives. If it matched one of the alternatives, but subsequently,
571        outside the recursion, there was a failure, the code tried to back up into
572        the recursion. However, because of the way PCRE is implemented, this is not
573        possible, and the result was an incorrect result from the match.
574    
575        In order to prevent this happening, the specification of recursion has
576        been changed so that all such subpatterns are automatically treated as
577        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
578    
579     4. I had overlooked the fact that, in some locales, there are characters for
580        which isalpha() is true but neither isupper() nor islower() are true. In
581        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
582        and ordfeminine) are like this. This affected the treatment of \w and \W
583        when they appeared in character classes, but not when they appeared outside
584        a character class. The bit map for "word" characters is now created
585        separately from the results of isalnum() instead of just taking it from the
586        upper, lower, and digit maps. (Plus the underscore character, of course.)
587    
588     5. The above bug also affected the handling of POSIX character classes such as
589        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
590        permanent tables. Instead, the bit maps for such a class were previously
591        created as the appropriate unions of the upper, lower, and digit bitmaps.
592        Now they are created by subtraction from the [[:word:]] class, which has
593        its own bitmap.
594    
595     6. The [[:blank:]] character class matches horizontal, but not vertical space.
596        It is created by subtracting the vertical space characters (\x09, \x0a,
597        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
598        subtraction was done in the overall bitmap for a character class, meaning
599        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
600        be recognized. This bug has been fixed.
601    
602     7. Patches from the folks at Google:
603    
604          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
605          real life, but is still worth protecting against".
606    
607          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
608          regular expressions".
609    
610          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
611          have it.
612    
613          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
614          "configure" and the latter not, in order to fix a problem somebody had
615          with compiling the Arg class on HP-UX.
616    
617          (e) Improve the error-handling of the C++ wrapper a little bit.
618    
619          (f) New tests for checking recursion limiting.
620    
621     8. The pcre_memmove() function, which is used only if the environment does not
622        have a standard memmove() function (and is therefore rarely compiled),
623        contained two bugs: (a) use of int instead of size_t, and (b) it was not
624        returning a result (though PCRE never actually uses the result).
625    
626     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
627        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
628        returned instead of calling malloc() with an overflowing number that would
629        most likely cause subsequent chaos.
630    
631    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
632    
633    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
634        with this option is matched, the nmatch and pmatch options of regexec() are
635        ignored.
636    
637    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
638        provided in case anyone wants to the the POSIX interface with UTF-8
639        strings.
640    
641    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
642        C++ linking (needed for some HP-UX environments).
643    
644    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
645        (unused parameter) and in the pcre_printint() function (omitted "default"
646        switch label when the default is to do nothing).
647    
648    15. Added some code to make it possible, when PCRE is compiled as a C++
649        library, to replace subject pointers for pcre_exec() with a smart pointer
650        class, thus making it possible to process discontinuous strings.
651    
652    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
653        much the same function. They were added by different people who were trying
654        to make PCRE easy to compile on non-Unix systems. It has been suggested
655        that PCRE_EXPORT be abolished now that there is more automatic apparatus
656        for compiling on Windows systems. I have therefore replaced it with
657        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
658        defaults to "extern" for C or "extern C" for C++, which works fine on
659        Unix-like systems. It is now possible to override the value of PCRE_DATA_
660        SCOPE with something explicit in config.h. In addition:
661    
662        (a) pcreposix.h still had just "extern" instead of either of these macros;
663            I have replaced it with PCRE_DATA_SCOPE.
664    
665        (b) Functions such as _pcre_xclass(), which are internal to the library,
666            but external in the C sense, all had PCRE_EXPORT in their definitions.
667            This is apparently wrong for the Windows case, so I have removed it.
668            (It makes no difference on Unix-like systems.)
669    
670    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
671        of recursive calls to match(). This is different to MATCH_LIMIT because
672        that limits the total number of calls to match(), not all of which increase
673        the depth of recursion. Limiting the recursion depth limits the amount of
674        stack (or heap if NO_RECURSE is set) that is used. The default can be set
675        when PCRE is compiled, and changed at run time. A patch from Google adds
676        this functionality to the C++ interface.
677    
678    18. Changes to the handling of Unicode character properties:
679    
680        (a) Updated the table to Unicode 4.1.0.
681    
682        (b) Recognize characters that are not in the table as "Cn" (undefined).
683    
684        (c) I revised the way the table is implemented to a much improved format
685            which includes recognition of ranges. It now supports the ranges that
686            are defined in UnicodeData.txt, and it also amalgamates other
687            characters into ranges. This has reduced the number of entries in the
688            table from around 16,000 to around 3,000, thus reducing its size
689            considerably. I realized I did not need to use a tree structure after
690            all - a binary chop search is just as efficient. Having reduced the
691            number of entries, I extended their size from 6 bytes to 8 bytes to
692            allow for more data.
693    
694        (d) Added support for Unicode script names via properties such as \p{Han}.
695    
696    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
697        matching that character.
698    
699    20. When matching a repeated Unicode property with a minimum greater than zero,
700        (for example \pL{2,}), PCRE could look past the end of the subject if it
701        reached it while seeking the minimum number of characters. This could
702        happen only if some of the characters were more than one byte long, because
703        there is a check for at least the minimum number of bytes.
704    
705    21. Refactored the implementation of \p and \P so as to be more general, to
706        allow for more different types of property in future. This has changed the
707        compiled form incompatibly. Anybody with saved compiled patterns that use
708        \p or \P will have to recompile them.
709    
710    22. Added "Any" and "L&" to the supported property types.
711    
712    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
713        but give a compile time error if the value is greater than 0xff.
714    
715    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
716        accidentally not being installed or uninstalled.
717    
718    25. The pcre.h file was built from pcre.h.in, but the only changes that were
719        made were to insert the current release number. This seemed silly, because
720        it made things harder for people building PCRE on systems that don't run
721        "configure". I have turned pcre.h into a distributed file, no longer built
722        by "configure", with the version identification directly included. There is
723        no longer a pcre.h.in file.
724    
725        However, this change necessitated a change to the pcre-config script as
726        well. It is built from pcre-config.in, and one of the substitutions was the
727        release number. I have updated configure.ac so that ./configure now finds
728        the release number by grepping pcre.h.
729    
730    26. Added the ability to run the tests under valgrind.
731    
732    
733    Version 6.4 05-Sep-05
734    ---------------------
735    
736     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
737        "--" to be printed when multiple files were scanned, even when none of the
738        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
739        consider it to be a bug, and have restored the previous behaviour.
740    
741     2. A couple of code tidies to get rid of compiler warnings.
742    
743     3. The pcretest program used to cheat by referring to symbols in the library
744        whose names begin with _pcre_. These are internal symbols that are not
745        really supposed to be visible externally, and in some environments it is
746        possible to suppress them. The cheating is now confined to including
747        certain files from the library's source, which is a bit cleaner.
748    
749     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
750        file's purpose clearer.
751    
752     5. Reorganized pcre_ucp_findchar().
753    
754    
755    Version 6.3 15-Aug-05
756    ---------------------
757    
758     1. The file libpcre.pc.in did not have general read permission in the tarball.
759    
760     2. There were some problems when building without C++ support:
761    
762        (a) If C++ support was not built, "make install" and "make test" still
763            tried to test it.
764    
765        (b) There were problems when the value of CXX was explicitly set. Some
766            changes have been made to try to fix these, and ...
767    
768        (c) --disable-cpp can now be used to explicitly disable C++ support.
769    
770        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
771            backslash in a target when C++ was disabled. This confuses some
772            versions of "make", apparently. Using an intermediate variable solves
773            this. (Same for CPP_LOBJ.)
774    
775     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
776        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
777        necessary on certain architectures.
778    
779     4. Added a setting of -export-symbols-regex to the link command to remove
780        those symbols that are exported in the C sense, but actually are local
781        within the library, and not documented. Their names all begin with
782        "_pcre_". This is not a perfect job, because (a) we have to except some
783        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
784        available (and never for static libraries). I have made a note to try to
785        find a way round (a) in the future.
786    
787    
788    Version 6.2 01-Aug-05
789    ---------------------
790    
791     1. There was no test for integer overflow of quantifier values. A construction
792        such as {1111111111111111} would give undefined results. What is worse, if
793        a minimum quantifier for a parenthesized subpattern overflowed and became
794        negative, the calculation of the memory size went wrong. This could have
795        led to memory overwriting.
796    
797     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
798    
799     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
800        operating environments where this matters.
801    
802     4. Applied Giuseppe Maxia's patch to add additional features for controlling
803        PCRE options from within the C++ wrapper.
804    
805     5. Named capturing subpatterns were not being correctly counted when a pattern
806        was compiled. This caused two problems: (a) If there were more than 100
807        such subpatterns, the calculation of the memory needed for the whole
808        compiled pattern went wrong, leading to an overflow error. (b) Numerical
809        back references of the form \12, where the number was greater than 9, were
810        not recognized as back references, even though there were sufficient
811        previous subpatterns.
812    
813     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
814        versions of gcc, e.g. 2.95.4.
815    
816    
817    Version 6.1 21-Jun-05
818    ---------------------
819    
820     1. There was one reference to the variable "posix" in pcretest.c that was not
821        surrounded by "#if !defined NOPOSIX".
822    
823     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
824        the cross-check on the old pcre_info() function, for the benefit of the
825        cut-down version of PCRE that is currently imported into Exim.
826    
827     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
828        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
829        patterns that start (?i) but I don't think that matters. The use of (?i) is
830        just an example; this all applies to the other options as well.
831    
832     4. Since libtool seems to echo the compile commands it is issuing, the output
833        from "make" can be reduced a bit by putting "@" in front of each libtool
834        compile command.
835    
836     5. Patch from the folks at Google for configure.in to be a bit more thorough
837        in checking for a suitable C++ installation before trying to compile the
838        C++ stuff. This should fix a reported problem when a compiler was present,
839        but no suitable headers.
840    
841     6. The man pages all had just "PCRE" as their title. I have changed them to
842        be the relevant file name. I have also arranged that these names are
843        retained in the file doc/pcre.txt, which is a concatenation in text format
844        of all the man pages except the little individual ones for each function.
845    
846     7. The NON-UNIX-USE file had not been updated for the different set of source
847        files that come with release 6. I also added a few comments about the C++
848        wrapper.
849    
850    
851    Version 6.0 07-Jun-05
852    ---------------------
853    
854     1. Some minor internal re-organization to help with my DFA experiments.
855    
856     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
857        didn't matter for the library itself when fully configured, but did matter
858        when compiling without UCP support, or within Exim, where the ucp files are
859        not imported.
860    
861     3. Refactoring of the library code to split up the various functions into
862        different source modules. The addition of the new DFA matching code (see
863        below) to a single monolithic source would have made it really too
864        unwieldy, quite apart from causing all the code to be include in a
865        statically linked application, when only some functions are used. This is
866        relevant even without the DFA addition now that patterns can be compiled in
867        one application and matched in another.
868    
869        The downside of splitting up is that there have to be some external
870        functions and data tables that are used internally in different modules of
871        the library but which are not part of the API. These have all had their
872        names changed to start with "_pcre_" so that they are unlikely to clash
873        with other external names.
874    
875     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
876        a different (DFA) algorithm. Although it is slower than the original
877        function, it does have some advantages for certain types of matching
878        problem.
879    
880     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
881        including restarting after a partial match.
882    
883     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
884        defined when compiling for Windows was sent to me. I have put it into the
885        code, though I have no means of testing or verifying it.
886    
887     7. Added the pcre_refcount() auxiliary function.
888    
889     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
890        match before or at the first newline in the subject string. In pcretest,
891        the /f option on a pattern can be used to set this.
892    
893     9. A repeated \w when used in UTF-8 mode with characters greater than 256
894        would behave wrongly. This has been present in PCRE since release 4.0.
895    
896    10. A number of changes to the pcregrep command:
897    
898        (a) Refactored how -x works; insert ^(...)$ instead of setting
899            PCRE_ANCHORED and checking the length, in preparation for adding
900            something similar for -w.
901    
902        (b) Added the -w (match as a word) option.
903    
904        (c) Refactored the way lines are read and buffered so as to have more
905            than one at a time available.
906    
907        (d) Implemented a pcregrep test script.
908    
909        (e) Added the -M (multiline match) option. This allows patterns to match
910            over several lines of the subject. The buffering ensures that at least
911            8K, or the rest of the document (whichever is the shorter) is available
912            for matching (and similarly the previous 8K for lookbehind assertions).
913    
914        (f) Changed the --help output so that it now says
915    
916              -w, --word-regex(p)
917    
918            instead of two lines, one with "regex" and the other with "regexp"
919            because that confused at least one person since the short forms are the
920            same. (This required a bit of code, as the output is generated
921            automatically from a table. It wasn't just a text change.)
922    
923        (g) -- can be used to terminate pcregrep options if the next thing isn't an
924            option but starts with a hyphen. Could be a pattern or a path name
925            starting with a hyphen, for instance.
926    
927        (h) "-" can be given as a file name to represent stdin.
928    
929        (i) When file names are being printed, "(standard input)" is used for
930            the standard input, for compatibility with GNU grep. Previously
931            "<stdin>" was used.
932    
933        (j) The option --label=xxx can be used to supply a name to be used for
934            stdin when file names are being printed. There is no short form.
935    
936        (k) Re-factored the options decoding logic because we are going to add
937            two more options that take data. Such options can now be given in four
938            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
939    
940        (l) Added the -A, -B, and -C options for requesting that lines of context
941            around matches be printed.
942    
943        (m) Added the -L option to print the names of files that do not contain
944            any matching lines, that is, the complement of -l.
945    
946        (n) The return code is 2 if any file cannot be opened, but pcregrep does
947            continue to scan other files.
948    
949        (o) The -s option was incorrectly implemented. For compatibility with other
950            greps, it now suppresses the error message for a non-existent or non-
951            accessible file (but not the return code). There is a new option called
952            -q that suppresses the output of matching lines, which was what -s was
953            previously doing.
954    
955        (p) Added --include and --exclude options to specify files for inclusion
956            and exclusion when recursing.
957    
958    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
959        Hopefully, it now does.
960    
961    12. Missing cast in pcre_study().
962    
963    13. Added an "uninstall" target to the makefile.
964    
965    14. Replaced "extern" in the function prototypes in Makefile.in with
966        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
967        world, but is set differently for Windows.
968    
969    15. Added a second compiling function called pcre_compile2(). The only
970        difference is that it has an extra argument, which is a pointer to an
971        integer error code. When there is a compile-time failure, this is set
972        non-zero, in addition to the error test pointer being set to point to an
973        error message. The new argument may be NULL if no error number is required
974        (but then you may as well call pcre_compile(), which is now just a
975        wrapper). This facility is provided because some applications need a
976        numeric error indication, but it has also enabled me to tidy up the way
977        compile-time errors are handled in the POSIX wrapper.
978    
979    16. Added VPATH=.libs to the makefile; this should help when building with one
980        prefix path and installing with another. (Or so I'm told by someone who
981        knows more about this stuff than I do.)
982    
983    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
984        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
985        match everything, including newlines. This is not POSIX-compatible, but
986        somebody wanted the feature. From pcretest it can be activated by using
987        both the P and the s flags.
988    
989    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
990    
991    19. libpcre.pc was being incorrectly installed as executable.
992    
993    20. A couple of places in pcretest check for end-of-line by looking for '\n';
994        it now also looks for '\r' so that it will work unmodified on Windows.
995    
996    21. Added Google's contributed C++ wrapper to the distribution.
997    
998    22. Added some untidy missing memory free() calls in pcretest, to keep
999        Electric Fence happy when testing.
1000    
1001    
1002    
1003    Version 5.0 13-Sep-04
1004    ---------------------
1005    
1006     1. Internal change: literal characters are no longer packed up into items
1007        containing multiple characters in a single byte-string. Each character
1008        is now matched using a separate opcode. However, there may be more than one
1009        byte in the character in UTF-8 mode.
1010    
1011     2. The pcre_callout_block structure has two new fields: pattern_position and
1012        next_item_length. These contain the offset in the pattern to the next match
1013        item, and its length, respectively.
1014    
1015     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1016        insertion of callouts before each pattern item. Added the /C option to
1017        pcretest to make use of this.
1018    
1019     4. On the advice of a Windows user, the lines
1020    
1021          #if defined(_WIN32) || defined(WIN32)
1022          _setmode( _fileno( stdout ), 0x8000 );
1023          #endif  /* defined(_WIN32) || defined(WIN32) */
1024    
1025        have been added to the source of pcretest. This apparently does useful
1026        magic in relation to line terminators.
1027    
1028     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1029        for the benefit of those environments where the "b" makes a difference.
1030    
1031     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1032        to know about it. I have put a hack into configure.in that adds in code
1033        to set GCC=yes if CC=icc. This seems to end up at a point in the
1034        generated configure script that is early enough to affect the setting of
1035        compiler options, which is what is needed, but I have no means of testing
1036        whether it really works. (The user who reported this had patched the
1037        generated configure script, which of course I cannot do.)
1038    
1039        LATER: After change 22 below (new libtool files), the configure script
1040        seems to know about icc (and also ecc). Therefore, I have commented out
1041        this hack in configure.in.
1042    
1043     7. Added support for pkg-config (2 patches were sent in).
1044    
1045     8. Negated POSIX character classes that used a combination of internal tables
1046        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1047        [[:^ascii]]. Typically, they would match almost any characters. The other
1048        POSIX classes were not broken in this way.
1049    
1050     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1051        to find the match, as PCRE was deluded into thinking that the match had to
1052        start at the start point or following a newline. The same bug applied to
1053        patterns with negative forward assertions or any backward assertions
1054        preceding ".*" at the start, unless the pattern required a fixed first
1055        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1056    
1057    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1058        starting at the last subject character, bytes beyond the end of the subject
1059        string were read.
1060    
1061    11. Renamed the variable "class" as "classbits" to make life easier for C++
1062        users. (Previously there was a macro definition, but it apparently wasn't
1063        enough.)
1064    
1065    12. Added the new field "tables" to the extra data so that tables can be passed
1066        in at exec time, or the internal tables can be re-selected. This allows
1067        a compiled regex to be saved and re-used at a later time by a different
1068        program that might have everything at different addresses.
1069    
1070    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1071        -R library as well as a -L library.
1072    
1073    14. The debugging options of pcretest (-d on the command line or D on a
1074        pattern) showed incorrect output for anything following an extended class
1075        that contained multibyte characters and which was followed by a quantifier.
1076    
1077    15. Added optional support for general category Unicode character properties
1078        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1079        support. It adds about 90K to the size of the library. The meanings of the
1080        inbuilt class escapes such as \d and \s have NOT been changed.
1081    
1082    16. Updated pcredemo.c to include calls to free() to release the memory for the
1083        compiled pattern.
1084    
1085    17. The generated file chartables.c was being created in the source directory
1086        instead of in the building directory. This caused the build to fail if the
1087        source directory was different from the building directory, and was
1088        read-only.
1089    
1090    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1091        file. No doubt somebody will tell me if they don't make sense... Also added
1092        Dan Mooney's comments about building on OpenVMS.
1093    
1094    19. Added support for partial matching via the PCRE_PARTIAL option for
1095        pcre_exec() and the \P data escape in pcretest.
1096    
1097    20. Extended pcretest with 3 new pattern features:
1098    
1099        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1100              write the compiled pattern to the file whose name is "rest-of-line".
1101              This is a straight binary dump of the data, with the saved pointer to
1102              the character tables forced to be NULL. The study data, if any, is
1103              written too. After writing, pcretest reads a new pattern.
1104    
1105        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1106              compiled pattern from the given file. There must not be any
1107              occurrences of "<" in the file name (pretty unlikely); if there are,
1108              pcretest will instead treat the initial "<" as a pattern delimiter.
1109              After reading in the pattern, pcretest goes on to read data lines as
1110              usual.
1111    
1112        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1113              and 16-bit fields in a compiled pattern, to simulate a pattern that
1114              was compiled on a host of opposite endianness.
1115    
1116    21. The pcre-exec() function can now cope with patterns that were compiled on
1117        hosts of opposite endianness, with this restriction:
1118    
1119          As for any compiled expression that is saved and used later, the tables
1120          pointer field cannot be preserved; the extra_data field in the arguments
1121          to pcre_exec() should be used to pass in a tables address if a value
1122          other than the default internal tables were used at compile time.
1123    
1124    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1125        now diagnosed as an error. Previously, most of the time, a negative number
1126        would have been treated as zero, but if in addition "ovector" was passed as
1127        NULL, a crash could occur.
1128    
1129    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1130        new versions from the libtool 1.5 distribution (the last one is a copy of
1131        a file called libtool.m4). This seems to have fixed the need to patch
1132        "configure" to support Darwin 1.3 (which I used to do). However, I still
1133        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1134        workstation).
1135    
1136    24. Changed the PCRE licence to be the more standard "BSD" licence.
1137    
1138    
1139    Version 4.5 01-Dec-03
1140    ---------------------
1141    
1142     1. There has been some re-arrangement of the code for the match() function so
1143        that it can be compiled in a version that does not call itself recursively.
1144        Instead, it keeps those local variables that need separate instances for
1145        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1146        needs to "recurse". Keeping track of where control must go is done by means
1147        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1148        hide most of the details from the main code, and operates only if
1149        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1150        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1151        operating.
1152    
1153        To make it easier for callers to provide specially tailored get/free
1154        functions for this usage, two new functions, pcre_stack_malloc, and
1155        pcre_stack_free, are used. They are always called in strict stacking order,
1156        and the size of block requested is always the same.
1157    
1158        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1159        PCRE has been compiled to use the stack or the heap for recursion. The
1160        -C option of pcretest uses this to show which version is compiled.
1161    
1162        A new data escape \S, is added to pcretest; it causes the amounts of store
1163        obtained and freed by both kinds of malloc/free at match time to be added
1164        to the output.
1165    
1166     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1167        what's available on my current Linux desktop machine.
1168    
1169     3. When matching a UTF-8 string, the test for a valid string at the start has
1170        been extended. If start_offset is not zero, PCRE now checks that it points
1171        to a byte that is the start of a UTF-8 character. If not, it returns
1172        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1173        this is necessary because there may be backward assertions in the pattern.
1174        When matching the same subject several times, it may save resources to use
1175        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1176    
1177     4. The code for checking the validity of UTF-8 strings has been tightened so
1178        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1179        containing "overlong sequences".
1180    
1181     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1182        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1183        should have been "&", but it just so happened that all the cases this let
1184        through by mistake were picked up later in the function.
1185    
1186     6. I had used a variable called "isblank" - this is a C99 function, causing
1187        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1188    
1189     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1190        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1191        so the version is shown; (c) stop "make test" echoing "./RunTest".
1192    
1193     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1194    
1195     9. The prototype for memmove() for systems that don't have it was using
1196        size_t, but the inclusion of the header that defines size_t was later. I've
1197        moved the #includes for the C headers earlier to avoid this.
1198    
1199    10. Added some adjustments to the code to make it easier to compiler on certain
1200        special systems:
1201    
1202          (a) Some "const" qualifiers were missing.
1203          (b) Added the macro EXPORT before all exported functions; by default this
1204              is defined to be empty.
1205          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1206              that it reads its output file name as an argument instead of writing
1207              to the standard output and assuming this can be redirected.
1208    
1209    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1210        class containing characters with values greater than 255, PCRE compilation
1211        went into a loop.
1212    
1213    12. A recursive reference to a subpattern that was within another subpattern
1214        that had a minimum quantifier of zero caused PCRE to crash. For example,
1215        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1216        recursion. If the recursively-called subpattern itself had a zero repeat,
1217        that was OK.
1218    
1219    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1220        buffer into which it was copied (for escape processing) was still set at
1221        1024, so long lines caused crashes.
1222    
1223    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1224        "internal error: code overflow...". This applied to any character class
1225        that was followed by a possessive quantifier.
1226    
1227    15. Modified the Makefile to add libpcre.la as a prerequisite for
1228        libpcreposix.la because I was told this is needed for a parallel build to
1229        work.
1230    
1231    16. If a pattern that contained .* following optional items at the start was
1232        studied, the wrong optimizing data was generated, leading to matching
1233        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1234        matching string must start with a or b or c. The correct conclusion for
1235        this pattern is that a match can start with any character.
1236    
1237    
1238    Version 4.4 13-Aug-03
1239    ---------------------
1240    
1241     1. In UTF-8 mode, a character class containing characters with values between
1242        127 and 255 was not handled correctly if the compiled pattern was studied.
1243        In fixing this, I have also improved the studying algorithm for such
1244        classes (slightly).
1245    
1246     2. Three internal functions had redundant arguments passed to them. Removal
1247        might give a very teeny performance improvement.
1248    
1249     3. Documentation bug: the value of the capture_top field in a callout is *one
1250        more than* the number of the hightest numbered captured substring.
1251    
1252     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1253        in incorrectly linking with a previously installed version. They now link
1254        explicitly with libpcre.la.
1255    
1256     5. configure.in no longer needs to recognize Cygwin specially.
1257    
1258     6. A problem in pcre.in for Windows platforms is fixed.
1259    
1260     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1261        pcretest, it used to include the size of the study block as part of its
1262        output. Unfortunately, the structure contains a field that has a different
1263        size on different hardware architectures. This meant that the tests that
1264        showed this size failed. As the block is currently always of a fixed size,
1265        this information isn't actually particularly useful in pcretest output, so
1266        I have just removed it.
1267    
1268     8. Three pre-processor statements accidentally did not start in column 1.
1269        Sadly, there are *still* compilers around that complain, even though
1270        standard C has not required this for well over a decade. Sigh.
1271    
1272     9. In pcretest, the code for checking callouts passed small integers in the
1273        callout_data field, which is a void * field. However, some picky compilers
1274        complained about the casts involved for this on 64-bit systems. Now
1275        pcretest passes the address of the small integer instead, which should get
1276        rid of the warnings.
1277    
1278    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1279        both compile and run time, and gives an error if an invalid UTF-8 sequence
1280        is found. There is a option for disabling this check in cases where the
1281        string is known to be correct and/or the maximum performance is wanted.
1282    
1283    11. In response to a bug report, I changed one line in Makefile.in from
1284    
1285            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1286        to
1287            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1288    
1289        to look similar to other lines, but I have no way of telling whether this
1290        is the right thing to do, as I do not use Windows. No doubt I'll get told
1291        if it's wrong...
1292    
1293    
1294    Version 4.3 21-May-03
1295    ---------------------
1296    
1297    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1298       Makefile.
1299    
1300    2. Some refactoring to improve the quality of the code:
1301    
1302       (i)   The utf8_table... variables are now declared "const".
1303    
1304       (ii)  The code for \cx, which used the "case flipping" table to upper case
1305             lower case letters, now just substracts 32. This is ASCII-specific,
1306             but the whole concept of \cx is ASCII-specific, so it seems
1307             reasonable.
1308    
1309       (iii) PCRE was using its character types table to recognize decimal and
1310             hexadecimal digits in the pattern. This is silly, because it handles
1311             only 0-9, a-f, and A-F, but the character types table is locale-
1312             specific, which means strange things might happen. A private
1313             table is now used for this - though it costs 256 bytes, a table is
1314             much faster than multiple explicit tests. Of course, the standard
1315             character types table is still used for matching digits in subject
1316             strings against \d.
1317    
1318       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1319             ending in _t are). So I've renamed it as ESC_tee.
1320    
1321    3. The first argument for regexec() in the POSIX wrapper should have been
1322       defined as "const".
1323    
1324    4. Changed pcretest to use malloc() for its buffers so that they can be
1325       Electric Fenced for debugging.
1326    
1327    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1328       to read one or more bytes before the start of the subject string. Often this
1329       had no effect on PCRE's behaviour, but in some circumstances it could
1330       provoke a segmentation fault.
1331    
1332    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1333       to try to read one or more bytes before the start of the subject string.
1334    
1335    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1336       UTF-8 support could misbehave in various ways if the subject string
1337       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1338       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1339       back over UTF-8 characters.)
1340    
1341    
1342    Version 4.2 14-Apr-03
1343    ---------------------
1344    
1345    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1346    
1347    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1348         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1349         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1350         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1351         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1352           and BUILD_EXEEXT
1353         Note: automatic setting of the BUILD variables is not yet working
1354         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1355           compile-time but not at link-time
1356         [LINK]: use for linking executables only
1357         make different versions for Windows and non-Windows
1358         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1359           libraries
1360         [LINK_FOR_BUILD]: new variable
1361         [OBJEXT]: use throughout
1362         [EXEEXT]: use throughout
1363         <winshared>: new target
1364         <wininstall>: new target
1365         <dftables.o>: use native compiler
1366         <dftables>: use native linker
1367         <install>: handle Windows platform correctly
1368         <clean>: ditto
1369         <check>: ditto
1370         copy DLL to top builddir before testing
1371    
1372       As part of these changes, -no-undefined was removed again. This was reported
1373       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1374       in any case.
1375    
1376    3. Some tidies to get rid of compiler warnings:
1377    
1378       . In the match_data structure, match_limit was an unsigned long int, whereas
1379         match_call_count was an int. I've made them both unsigned long ints.
1380    
1381       . In pcretest the fact that a const uschar * doesn't automatically cast to
1382         a void * provoked a warning.
1383    
1384       . Turning on some more compiler warnings threw up some "shadow" variables
1385         and a few more missing casts.
1386    
1387    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1388       option, a class that contained a single character with a value between 128
1389       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1390    
1391    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1392       option, a class that contained several characters, but with at least one
1393       whose value was between 128 and 255 caused PCRE to crash.
1394    
1395    
1396    Version 4.1 12-Mar-03
1397    ---------------------
1398    
1399    1. Compiling with gcc -pedantic found a couple of places where casts were
1400    needed, and a string in dftables.c that was longer than standard compilers are
1401    required to support.
1402    
1403    2. Compiling with Sun's compiler found a few more places where the code could
1404    be tidied up in order to avoid warnings.
1405    
1406    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1407    first of these names is deprecated in the latest Autoconf in favour of the name
1408    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1409    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1410    analogy I have changed it to CFLAGS_FOR_BUILD.
1411    
1412    4. Added -no-undefined to the linking command in the Makefile, because this is
1413    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1414    linking step for the pcreposix library.
1415    
1416    5. PCRE was failing to diagnose the case of two named groups with the same
1417    name.
1418    
1419    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1420    literal character that is needed in the subject for a match, and scans along to
1421    ensure that it is present before embarking on the full matching process. This
1422    saves time in cases of nested unlimited repeats that are never going to match.
1423    Problem: the scan can take a lot of time if the subject is very long (e.g.
1424    megabytes), thus penalizing straightforward matches. It is now done only if the
1425    amount of subject to be scanned is less than 1000 bytes.
1426    
1427    7. A lesser problem with the same optimization is that it was recording the
1428    first character of an anchored pattern as "needed", thus provoking a search
1429    right along the subject, even when the first match of the pattern was going to
1430    fail. The "needed" character is now not set for anchored patterns, unless it
1431    follows something in the pattern that is of non-fixed length. Thus, it still
1432    fulfils its original purpose of finding quick non-matches in cases of nested
1433    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1434    
1435    
1436    Version 4.0 17-Feb-03
1437    ---------------------
1438    
1439    1. If a comment in an extended regex that started immediately after a meta-item
1440    extended to the end of string, PCRE compiled incorrect data. This could lead to
1441    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1442    
1443    2. Moved to autoconf 2.53 and libtool 1.4.2.
1444    
1445    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1446    the special perltest8 script is no longer needed - all the tests can be run
1447    from a single perltest script.
1448    
1449    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1450    by \s. It has now been removed in PCRE. This means it isn't recognized as
1451    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1452    class [:space:] *does* include VT, thereby creating a mess.
1453    
1454    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1455    space and tab.
1456    
1457    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1458    its new features into the main test script, reducing the number of scripts.
1459    
1460    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1461    were backward compatible, and made the (?i) apply to the whole pattern, as if
1462    /i were given. Now it behaves more logically, and applies the option setting
1463    only to what follows. PCRE has been changed to follow suit. However, if it
1464    finds options settings right at the start of the pattern, it extracts them into
1465    the global options, as before. Thus, they show up in the info data.
1466    
1467    8. Added support for the \Q...\E escape sequence. Characters in between are
1468    treated as literals. This is slightly different from Perl in that $ and @ are
1469    also handled as literals inside the quotes. In Perl, they will cause variable
1470    interpolation. Note the following examples:
1471    
1472        Pattern            PCRE matches      Perl matches
1473    
1474        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1475        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1476        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1477    
1478    For compatibility with Perl, \Q...\E sequences are recognized inside character
1479    classes as well as outside them.
1480    
1481    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1482    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1483    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1484    signed/unsigned warnings.
1485    
1486    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1487    option for pcretest, so I've replaced it by a simple function that does just
1488    that job.
1489    
1490    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1491    "pcregrep -".
1492    
1493    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1494    Java package. This provides some syntactic sugar for simple cases of what my
1495    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1496    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1497    item, you can use this simplified notation. Note that only makes sense with
1498    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1499    greediness, whatever the setting of the PCRE_UNGREEDY option.
1500    
1501    13. A change of greediness default within a pattern was not taking effect at
1502    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1503    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1504    was abstracted outside.
1505    
1506    14. PCRE now supports the \G assertion. It is true when the current matching
1507    position is at the start point of the match. This differs from \A when the
1508    starting offset is non-zero. Used with the /g option of pcretest (or similar
1509    code), it works in the same way as it does for Perl's /g option. If all
1510    alternatives of a regex begin with \G, the expression is anchored to the start
1511    match position, and the "anchored" flag is set in the compiled expression.
1512    
1513    15. Some bugs concerning the handling of certain option changes within patterns
1514    have been fixed. These applied to options other than (?ims). For example,
1515    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1516    been the other way round. Some of this was related to change 7 above.
1517    
1518    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1519    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1520    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1521    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1522    
1523    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1524    mode. Unlike ".", it always matches newline, whatever the setting of
1525    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1526    assertions. Perl allows it, but it doesn't (in general) work because it can't
1527    calculate the length of the lookbehind. At least, that's the case for Perl
1528    5.8.0 - I've been told they are going to document that it doesn't work in
1529    future.
1530    
1531    18. Added an error diagnosis for escapes that PCRE does not support: these are
1532    \L, \l, \N, \P, \p, \U, \u, and \X.
1533    
1534    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1535    reading past the end of the pattern in cases such as /[abcd/.
1536    
1537    20. PCRE was getting more memory than necessary for patterns with classes that
1538    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1539    
1540    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1541    compiling PCRE for use with Virtual Pascal.
1542    
1543    22. Small fix to the Makefile to make it work properly if the build is done
1544    outside the source tree.
1545    
1546    23. Added a new extension: a condition to go with recursion. If a conditional
1547    subpattern starts with (?(R) the "true" branch is used if recursion has
1548    happened, whereas the "false" branch is used only at the top level.
1549    
1550    24. When there was a very long string of literal characters (over 255 bytes
1551    without UTF support, over 250 bytes with UTF support), the computation of how
1552    much memory was required could be incorrect, leading to segfaults or other
1553    strange effects.
1554    
1555    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1556    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1557    there was a subsequent back reference to those brackets. This meant that, for
1558    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1559    possible to check for precisely this case. All we can do is abandon the
1560    optimization if .* occurs inside capturing brackets when there are any back
1561    references whatsoever. (See below for a better fix that came later.)
1562    
1563    26. The handling of the optimization for finding the first character of a
1564    non-anchored pattern, and for finding a character that is required later in the
1565    match were failing in some cases. This didn't break the matching; it just
1566    failed to optimize when it could. The way this is done has been re-implemented.
1567    
1568    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1569    
1570    28. Added a new feature that provides some of the functionality that Perl
1571    provides with (?{...}). The facility is termed a "callout". The way it is done
1572    in PCRE is for the caller to provide an optional function, by setting
1573    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1574    global variable. By default it is unset, which disables all calling out. To get
1575    the function called, the regex must include (?C) at appropriate points. This
1576    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1577    This provides a means of identifying different callout points. When PCRE
1578    reaches such a point in the regex, if pcre_callout has been set, the external
1579    function is called. It is provided with data in a structure called
1580    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1581    matching continues; if it returns a non-zero value, the match at the current
1582    point fails. However, backtracking will occur if possible. [This was changed
1583    later and other features added - see item 49 below.]
1584    
1585    29. pcretest is upgraded to test the callout functionality. It provides a
1586    callout function that displays information. By default, it shows the start of
1587    the match and the current position in the text. There are some new data escapes
1588    to vary what happens:
1589    
1590        \C+         in addition, show current contents of captured substrings
1591        \C-         do not supply a callout function
1592        \C!n        return 1 when callout number n is reached
1593        \C!n!m      return 1 when callout number n is reached for the mth time
1594    
1595    30. If pcregrep was called with the -l option and just a single file name, it
1596    output "<stdin>" if a match was found, instead of the file name.
1597    
1598    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1599    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1600    pcre_exec(). This saves a malloc/free per call. The default value of
1601    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1602    when configuring.
1603    
1604    32. The default maximum size of a compiled pattern is 64K. There have been a
1605    few cases of people hitting this limit. The code now uses macros to handle the
1606    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1607    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1608    configuring. Tests 2 and 5 work only with 2-byte links because they output
1609    debugging information about compiled patterns.
1610    
1611    33. Internal code re-arrangements:
1612    
1613    (a) Moved the debugging function for printing out a compiled regex into
1614        its own source file (printint.c) and used #include to pull it into
1615        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1616        separate copies.
1617    
1618    (b) Defined the list of op-code names for debugging as a macro in
1619        internal.h so that it is next to the definition of the opcodes.
1620    
1621    (c) Defined a table of op-code lengths for simpler skipping along compiled
1622        code. This is again a macro in internal.h so that it is next to the
1623        definition of the opcodes.
1624    
1625    34. Added support for recursive calls to individual subpatterns, along the
1626    lines of Robin Houston's patch (but implemented somewhat differently).
1627    
1628    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1629    allow it to read and process whole directories in Win32. This code was
1630    contributed by Lionel Fourquaux; it has not been tested by me.
1631    
1632    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1633    used to name a group. Names consist of alphanumerics and underscores, and must
1634    be unique. Back references use the syntax (?P=name) and recursive calls use
1635    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1636    numbers. The function pcre_fullinfo() can be used after compilation to extract
1637    a name/number map. There are three relevant calls:
1638    
1639      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1640      PCRE_INFO_NAMECOUNT            yields the number of entries
1641      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1642    
1643    The map is a vector of fixed-size entries. The size of each entry depends on
1644    the length of the longest name used. The first two bytes of each entry are the
1645    group number, most significant byte first. There follows the corresponding
1646    name, zero terminated. The names are in alphabetical order.
1647    
1648    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1649    case instead of 255. Making it the same both with and without UTF-8 support
1650    means that the same test output works with both.
1651    
1652    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1653    calling malloc() with a zero argument.
1654    
1655    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1656    optimization. I've improved things by keeping a bitmap of backreferences with
1657    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1658    fact referenced, the optimization can be applied. It is unlikely that a
1659    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1660    the match to follow \n) will appear inside brackets with a number greater than
1661    31, but if it does, any back reference > 31 suppresses the optimization.
1662    
1663    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1664    of disabling numbered capturing parentheses. Any opening parenthesis that is
1665    not followed by ? behaves as if it were followed by ?: but named parentheses
1666    can still be used for capturing (and they will acquire numbers in the usual
1667    way).
1668    
1669    41. Redesigned the return codes from the match() function into yes/no/error so
1670    that errors can be passed back from deep inside the nested calls. A malloc
1671    failure while inside a recursive subpattern call now causes the
1672    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1673    
1674    42. It is now possible to set a limit on the number of times the match()
1675    function is called in a call to pcre_exec(). This facility makes it possible to
1676    limit the amount of recursion and backtracking, though not in a directly
1677    obvious way, because the match() function is used in a number of different
1678    circumstances. The count starts from zero for each position in the subject
1679    string (for non-anchored patterns). The default limit is, for compatibility, a
1680    large number, namely 10 000 000. You can change this in two ways:
1681    
1682    (a) When configuring PCRE before making, you can use --with-match-limit=n
1683        to set a default value for the compiled library.
1684    
1685    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1686        a different value is set. See 45 below.
1687    
1688    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1689    
1690    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1691    of things that can be changed at compile time. The first argument specifies
1692    what is wanted and the second points to where the information is to be placed.
1693    The current list of available information is:
1694    
1695      PCRE_CONFIG_UTF8
1696    
1697    The output is an integer that is set to one if UTF-8 support is available;
1698    otherwise it is set to zero.
1699    
1700      PCRE_CONFIG_NEWLINE
1701    
1702    The output is an integer that it set to the value of the code that is used for
1703    newline. It is either LF (10) or CR (13).
1704    
1705      PCRE_CONFIG_LINK_SIZE
1706    
1707    The output is an integer that contains the number of bytes used for internal
1708    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1709    
1710      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1711    
1712    The output is an integer that contains the threshold above which the POSIX
1713    interface uses malloc() for output vectors. See item 31 above.
1714    
1715      PCRE_CONFIG_MATCH_LIMIT
1716    
1717    The output is an unsigned integer that contains the default limit of the number
1718    of match() calls in a pcre_exec() execution. See 42 above.
1719    
1720    44. pcretest has been upgraded by the addition of the -C option. This causes it
1721    to extract all the available output from the new pcre_config() function, and to
1722    output it. The program then exits immediately.
1723    
1724    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1725    order to support additional features. One way would have been to define
1726    pcre_exec2() (for example) with extra arguments, but this would not have been
1727    extensible, and would also have required all calls to the original function to
1728    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1729    is used for passing in "extra" data from pcre_study().
1730    
1731    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1732    contains the following fields:
1733    
1734      flags         a bitmap indicating which of the following fields are set
1735      study_data    opaque data from pcre_study()
1736      match_limit   a way of specifying a limit on match() calls for a specific
1737                      call to pcre_exec()
1738      callout_data  data for callouts (see 49 below)
1739    
1740    The flag bits are also defined in pcre.h, and are
1741    
1742      PCRE_EXTRA_STUDY_DATA
1743      PCRE_EXTRA_MATCH_LIMIT
1744      PCRE_EXTRA_CALLOUT_DATA
1745    
1746    The pcre_study() function now returns one of these new pcre_extra blocks, with
1747    the actual study data pointed to by the study_data field, and the
1748    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1749    before. That is, this change is entirely upwards-compatible and requires no
1750    change to existing code.
1751    
1752    If you want to pass in additional data to pcre_exec(), you can either place it
1753    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1754    block.
1755    
1756    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1757    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1758    times with different match limits, until it finds the minimum value needed for
1759    pcre_exec() to complete. The value is then output. This can be instructive; for
1760    most simple matches the number is quite small, but for pathological cases it
1761    gets very large very quickly.
1762    
1763    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1764    returns the size of the data block pointed to by the study_data field in a
1765    pcre_extra block, that is, the value that was passed as the argument to
1766    pcre_malloc() when PCRE was getting memory in which to place the information
1767    created by pcre_study(). The fourth argument should point to a size_t variable.
1768    pcretest has been extended so that this information is shown after a successful
1769    pcre_study() call when information about the compiled regex is being displayed.
1770    
1771    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1772    because what follows is always an absolute path. (Later: it turns out that this
1773    is more than cosmetic for MinGW, because it doesn't like empty path
1774    components.)
1775    
1776    49. Some changes have been made to the callout feature (see 28 above):
1777    
1778    (i)  A callout function now has three choices for what it returns:
1779    
1780           0  =>  success, carry on matching
1781         > 0  =>  failure at this point, but backtrack if possible
1782         < 0  =>  serious error, return this value from pcre_exec()
1783    
1784         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1785         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1786         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1787         use by callout functions. It will never be used by PCRE itself.
1788    
1789    (ii) The pcre_extra structure (see 45 above) has a void * field called
1790         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1791         pcre_callout_block structure has a field of the same name. The contents of
1792         the field passed in the pcre_extra structure are passed to the callout
1793         function in the corresponding field in the callout block. This makes it
1794         easier to use the same callout-containing regex from multiple threads. For
1795         testing, the pcretest program has a new data escape
1796    
1797           \C*n        pass the number n (may be negative) as callout_data
1798    
1799         If the callout function in pcretest receives a non-zero value as
1800         callout_data, it returns that value.
1801    
1802    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1803    there were some redundant $(CFLAGS) in commands that are now specified as
1804    $(LINK), which already includes $(CFLAGS).
1805    
1806    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1807    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1808    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1809    one-byte characters throughout. Note that case-insensitive matching applies
1810    only to characters whose values are less than 256. PCRE doesn't support the
1811    notion of cases for higher-valued characters.
1812    
1813    (i)   A character class whose characters are all within 0-255 is handled as
1814          a bit map, and the map is inverted for negative classes. Previously, a
1815          character > 255 always failed to match such a class; however it should
1816          match if the class was a negative one (e.g. [^ab]). This has been fixed.
1817    
1818    (ii)  A negated character class with a single character < 255 is coded as
1819          "not this character" (OP_NOT). This wasn't working properly when the test
1820          character was multibyte, either singly or repeated.
1821    
1822    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1823          mode, for example: \x{100}{2,3}.
1824    
1825    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1826          singly or repeated) now correctly test multibyte characters. However,
1827          PCRE doesn't recognize any characters with values greater than 255 as
1828          digits, spaces, or word characters. Such characters always match \D, \S,
1829          and \W, and never match \d, \s, or \w.
1830    
1831    (v)   Classes may now contain characters and character ranges with values
1832          greater than 255. For example: [ab\x{100}-\x{400}].
1833    
1834    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
1835          PCRE in UTF-8 mode.
1836    
1837    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1838    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1839    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1840    value.)
1841    
1842    53. The single man page has become too large. I have therefore split it up into
1843    a number of separate man pages. These also give rise to individual HTML pages;
1844    these are now put in a separate directory, and there is an index.html page that
1845    lists them all. Some hyperlinking between the pages has been installed.
1846    
1847    54. Added convenience functions for handling named capturing parentheses.
1848    
1849    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1850    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1851    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1852    are faulted.
1853    
1854    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1855    calling configure. These values are used when compiling the dftables.c program
1856    which is run to generate the source of the default character tables. They
1857    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1858    you will need to set these values.
1859    
1860    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1861    
1862    
1863    Version 3.9 02-Jan-02
1864    ---------------------
1865    
1866    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1867    
1868    2. If --disable-static was given, the building process failed when trying to
1869    build pcretest and pcregrep. (For some reason it was using libtool to compile
1870    them, which is not right, as they aren't part of the library.)
1871    
1872    
1873    Version 3.8 18-Dec-01
1874    ---------------------
1875    
1876    1. The experimental UTF-8 code was completely screwed up. It was packing the
1877    bytes in the wrong order. How dumb can you get?
1878    
1879    
1880    Version 3.7 29-Oct-01
1881    ---------------------
1882    
1883    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1884    This caused pcretest, when used on the test data, to segfault. Unfortunately,
1885    this didn't happen under Solaris 8, where I normally test things.
1886    
1887    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1888    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1889    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1890    this fix an hour or so after the initial 3.7 release.)
1891    
1892    
1893    Version 3.6 23-Oct-01
1894    ---------------------
1895    
1896    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1897    offsets passed as NULL with zero offset count.
1898    
1899    2. The config.guess and config.sub files had not been updated when I moved to
1900    the latest autoconf.
1901    
1902    
1903  Version 3.5 15-Aug-01  Version 3.5 15-Aug-01
1904  ---------------------  ---------------------
1905    

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