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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.1 05-Mar-07
5    ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The 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.
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).
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.
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.
42    Version 7.0 19-Dec-06
43    ---------------------
45     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
46        moving to gcc 4.1.1.
48     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
49        sys/time.h, which is documented as needed for this function. It doesn't
50        seem to matter on Linux, but it showed up on some releases of OS X.
52     3. It seems that there are systems where bytes whose values are greater than
53        127 match isprint() in the "C" locale. The "C" locale should be the
54        default when a C program starts up. In most systems, only ASCII printing
55        characters match isprint(). This difference caused the output from pcretest
56        to vary, making some of the tests fail. I have changed pcretest so that:
58        (a) When it is outputting text in the compiled version of a pattern, bytes
59            other than 32-126 are always shown as hex escapes.
61        (b) When it is outputting text that is a matched part of a subject string,
62            it does the same, unless a different locale has been set for the match
63            (using the /L modifier). In this case, it uses isprint() to decide.
65     4. Fixed a major bug that caused incorrect computation of the amount of memory
66        required for a compiled pattern when options that changed within the
67        pattern affected the logic of the preliminary scan that determines the
68        length. The relevant options are -x, and -i in UTF-8 mode. The result was
69        that the computed length was too small. The symptoms of this bug were
70        either the PCRE error "internal error: code overflow" from pcre_compile(),
71        or a glibc crash with a message such as "pcretest: free(): invalid next
72        size (fast)". Examples of patterns that provoked this bug (shown in
73        pcretest format) are:
75          /(?-x: )/x
76          /(?x)(?-x: \s*#\s*)/
77          /((?i)[\x{c0}])/8
78          /(?i:[\x{c0}])/8
80        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
81        is now done differently.
83     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
84        wrapper classes; (b) implement a new function in the C++ scanner that is
85        more efficient than the old way of doing things because it avoids levels of
86        recursion in the regex matching; (c) add a paragraph to the documentation
87        for the FullMatch() function.
89     6. The escape sequence \n was being treated as whatever was defined as
90        "newline". Not only was this contrary to the documentation, which states
91        that \n is character 10 (hex 0A), but it also went horribly wrong when
92        "newline" was defined as CRLF. This has been fixed.
94     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
95        was being set to -1 for the "end of line" case (supposedly a value that no
96        character can have). Though this value is never used (the check for end of
97        line is "zero bytes in current character"), it caused compiler complaints.
98        I've changed it to 0xffffffff.
100     8. In pcre_version.c, the version string was being built by a sequence of
101        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
102        string (as it is for production releases) called a macro with an empty
103        argument. The C standard says the result of this is undefined. The gcc
104        compiler treats it as an empty string (which was what was wanted) but it is
105        reported that Visual C gives an error. The source has been hacked around to
106        avoid this problem.
108     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
109        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
110        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
111        of them did).
113    10. Originally, pcretest opened its input and output without "b"; then I was
114        told that "b" was needed in some environments, so it was added for release
115        5.0 to both the input and output. (It makes no difference on Unix-like
116        systems.) Later I was told that it is wrong for the input on Windows. I've
117        now abstracted the modes into two macros, to make it easier to fiddle with
118        them, and removed "b" from the input mode under Windows.
120    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
122    12. Added -help and --help to pcretest as an official way of being reminded
123        of the options.
125    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
126        and pcrecpp.cc because they annoy compilers at high warning levels.
128    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
130    15. Fixed an occurrence of == in configure.ac that should have been = (shell
131        scripts are not C programs :-) and which was not noticed because it works
132        on Linux.
134    16. pcretest is supposed to handle any length of pattern and data line (as one
135        line or as a continued sequence of lines) by extending its input buffer if
136        necessary. This feature was broken for very long pattern lines, leading to
137        a string of junk being passed to pcre_compile() if the pattern was longer
138        than about 50K.
140    17. I have done a major re-factoring of the way pcre_compile() computes the
141        amount of memory needed for a compiled pattern. Previously, there was code
142        that made a preliminary scan of the pattern in order to do this. That was
143        OK when PCRE was new, but as the facilities have expanded, it has become
144        harder and harder to keep it in step with the real compile phase, and there
145        have been a number of bugs (see for example, 4 above). I have now found a
146        cunning way of running the real compile function in a "fake" mode that
147        enables it to compute how much memory it would need, while actually only
148        ever using a few hundred bytes of working memory and without too many
149        tests of the mode. This should make future maintenance and development
150        easier. A side effect of this work is that the limit of 200 on the nesting
151        depth of parentheses has been removed (though this was never a serious
152        limitation, I suspect). However, there is a downside: pcre_compile() now
153        runs more slowly than before (30% or more, depending on the pattern). I
154        hope this isn't a big issue. There is no effect on runtime performance.
156    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
157        newline (only possible for the last line of a file) and it was a
158        pattern that set a locale (followed by /Lsomething), pcretest crashed.
160    19. Added additional timing features to pcretest. (1) The -tm option now times
161        matching only, not compiling. (2) Both -t and -tm can be followed, as a
162        separate command line item, by a number that specifies the number of
163        repeats to use when timing. The default is 50000; this gives better
164        precision, but takes uncomfortably long for very large patterns.
166    20. Extended pcre_study() to be more clever in cases where a branch of a
167        subpattern has no definite first character. For example, (a*|b*)[cd] would
168        previously give no result from pcre_study(). Now it recognizes that the
169        first character must be a, b, c, or d.
171    21. There was an incorrect error "recursive call could loop indefinitely" if
172        a subpattern (or the entire pattern) that was being tested for matching an
173        empty string contained only one non-empty item after a nested subpattern.
174        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
175        incorrectly, because the \d was being skipped in the check.
177    22. The pcretest program now has a new pattern option /B and a command line
178        option -b, which is equivalent to adding /B to every pattern. This causes
179        it to show the compiled bytecode, without the additional information that
180        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
181        is the same as /B/I).
183    23. A new optimization is now able automatically to treat some sequences such
184        as a*b as a*+b. More specifically, if something simple (such as a character
185        or a simple class like \d) has an unlimited quantifier, and is followed by
186        something that cannot possibly match the quantified thing, the quantifier
187        is automatically "possessified".
189    24. A recursive reference to a subpattern whose number was greater than 39
190        went wrong under certain circumstances in UTF-8 mode. This bug could also
191        have affected the operation of pcre_study().
193    25. Realized that a little bit of performance could be had by replacing
194        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
196    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
198    27. Possessive quantifiers such as a++ were previously implemented by turning
199        them into atomic groups such as ($>a+). Now they have their own opcodes,
200        which improves performance. This includes the automatically created ones
201        from 23 above.
203    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
204        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
205        the first matched character to be a colon. This applied both to named and
206        numbered groups.
208    29. The ucpinternal.h header file was missing its idempotency #ifdef.
210    30. I was sent a "project" file called libpcre.a.dev which I understand makes
211        building PCRE on Windows easier, so I have included it in the distribution.
213    31. There is now a check in pcretest against a ridiculously large number being
214        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
215        loop, the loop is abandoned.
217    32. Forward references to subpatterns in conditions such as (?(2)...) where
218        subpattern 2 is defined later cause pcre_compile() to search forwards in
219        the pattern for the relevant set of parentheses. This search went wrong
220        when there were unescaped parentheses in a character class, parentheses
221        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
223    33. "Subroutine" calls and backreferences were previously restricted to
224        referencing subpatterns earlier in the regex. This restriction has now
225        been removed.
227    34. Added a number of extra features that are going to be in Perl 5.10. On the
228        whole, these are just syntactic alternatives for features that PCRE had
229        previously implemented using the Python syntax or my own invention. The
230        other formats are all retained for compatibility.
232        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
233            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
234            also .NET compatible.
236        (b) A recursion or subroutine call to a named group can now be defined as
237            (?&name) as well as (?P>name).
239        (c) A backreference to a named group can now be defined as \k<name> or
240            \k'name' as well as (?P=name). The new forms, as well as being in Perl
241            5.10, are also .NET compatible.
243        (d) A conditional reference to a named group can now use the syntax
244            (?(<name>) or (?('name') as well as (?(name).
246        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
247            groups (named and numbered) that are never evaluated inline, but can be
248            called as "subroutines" from elsewhere. In effect, the DEFINE condition
249            is always false. There may be only one alternative in such a group.
251        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
252            as the simple (?(R). The condition is true only if the most recent
253            recursion is that of the given number or name. It does not search out
254            through the entire recursion stack.
256        (g) The escape \gN or \g{N} has been added, where N is a positive or
257            negative number, specifying an absolute or relative reference.
259    35. Tidied to get rid of some further signed/unsigned compiler warnings and
260        some "unreachable code" warnings.
262    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
263        things, this adds five new scripts.
265    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
266        There were also incompatibilities regarding the handling of \Q..\E inside
267        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
268        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
270    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
271        matches an empty string, and forcibly breaks the loop. There were bugs in
272        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
273        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
274        separate and independent bugs (that affected different cases) have been
275        fixed.
277    39. Refactored the code to abolish the use of different opcodes for small
278        capturing bracket numbers. This is a tidy that I avoided doing when I
279        removed the limit on the number of capturing brackets for 3.5 back in 2001.
280        The new approach is not only tidier, it makes it possible to reduce the
281        memory needed to fix the previous bug (38).
283    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
284        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
285        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
286        mode.
288    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
289        report.
291    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
292        copy construction and assignment in the C++ wrapper.
294    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
295        couple of bugs that could have given wrong results in the "--newline=crlf"
296        case.
298    44. Added a number of casts and did some reorganization of signed/unsigned int
299        variables following suggestions from Dair Grant. Also renamed the variable
300        "this" as "item" because it is a C++ keyword.
302    45. Arranged for dftables to add
304          #include "pcre_internal.h"
306        to pcre_chartables.c because without it, gcc 4.x may remove the array
307        definition from the final binary if PCRE is built into a static library and
308        dead code stripping is activated.
310    46. For an unanchored pattern, if a match attempt fails at the start of a
311        newline sequence, and the newline setting is CRLF or ANY, and the next two
312        characters are CRLF, advance by two characters instead of one.
315    Version 6.7 04-Jul-06
316    ---------------------
318     1. In order to handle tests when input lines are enormously long, pcretest has
319        been re-factored so that it automatically extends its buffers when
320        necessary. The code is crude, but this _is_ just a test program. The
321        default size has been increased from 32K to 50K.
323     2. The code in pcre_study() was using the value of the re argument before
324        testing it for NULL. (Of course, in any sensible call of the function, it
325        won't be NULL.)
327     3. The memmove() emulation function in pcre_internal.h, which is used on
328        systems that lack both memmove() and bcopy() - that is, hardly ever -
329        was missing a "static" storage class specifier.
331     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
332        containing an extended class (one that cannot be represented by a bitmap
333        because it contains high-valued characters or Unicode property items, e.g.
334        [\pZ]). Almost always one would set UTF-8 mode when processing such a
335        pattern, but PCRE should not loop if you do not (it no longer does).
336        [Detail: two cases were found: (a) a repeated subpattern containing an
337        extended class; (b) a recursive reference to a subpattern that followed a
338        previous extended class. It wasn't skipping over the extended class
339        correctly when UTF-8 mode was not set.]
341     5. A negated single-character class was not being recognized as fixed-length
342        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
343        compile error "lookbehind assertion is not fixed length".
345     6. The RunPerlTest auxiliary script was showing an unexpected difference
346        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
347        write a Perl script that can interpret lines of an input file either as
348        byte characters or as UTF-8, which is what "perltest" was being required to
349        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
350        can't do is switch easily at run time between having the "use utf8;" pragma
351        or not. In the end, I fudged it by using the RunPerlTest script to insert
352        "use utf8;" explicitly for the UTF-8 tests.
354     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
355        the end of the subject string, contrary to the documentation and to what
356        Perl does. This was true of both matching functions. Now it matches only at
357        the start of the subject and immediately after *internal* newlines.
359     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
360        a pointer to an int instead of a pointer to an unsigned long int. This
361        caused problems on 64-bit systems.
363     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
364        instance of the 'standard' template library not being so standard".
366    10. There was no check on the number of named subpatterns nor the maximum
367        length of a subpattern name. The product of these values is used to compute
368        the size of the memory block for a compiled pattern. By supplying a very
369        long subpattern name and a large number of named subpatterns, the size
370        computation could be caused to overflow. This is now prevented by limiting
371        the length of names to 32 characters, and the number of named subpatterns
372        to 10,000.
374    11. Subpatterns that are repeated with specific counts have to be replicated in
375        the compiled pattern. The size of memory for this was computed from the
376        length of the subpattern and the repeat count. The latter is limited to
377        65535, but there was no limit on the former, meaning that integer overflow
378        could in principle occur. The compiled length of a repeated subpattern is
379        now limited to 30,000 bytes in order to prevent this.
381    12. Added the optional facility to have named substrings with the same name.
383    13. Added the ability to use a named substring as a condition, using the
384        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
385        are numbers (not recommended). Forward references are permitted.
387    14. Added forward references in named backreferences (if you see what I mean).
389    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
390        pattern could run off the end of the subject. For example, the pattern
391        "(?s)(.{1,5})"8 did this with the subject "ab".
393    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
394        PCRE_CASELESS was set when matching characters that were quantified with ?
395        or *.
397    17. A character class other than a single negated character that had a minimum
398        but no maximum quantifier - for example [ab]{6,} - was not handled
399        correctly by pce_dfa_exec(). It would match only one character.
401    18. A valid (though odd) pattern that looked like a POSIX character
402        class but used an invalid character after [ (for example [[,abc,]]) caused
403        pcre_compile() to give the error "Failed: internal error: code overflow" or
404        in some cases to crash with a glibc free() error. This could even happen if
405        the pattern terminated after [[ but there just happened to be a sequence of
406        letters, a binary zero, and a closing ] in the memory that followed.
408    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
409        over the years. Originally (before any Unicode support), just the bottom 8
410        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
411        output from "man perlunicode" includes this:
413          The regular expression compiler produces polymorphic opcodes.  That
414          is, the pattern adapts to the data and automatically switches to
415          the Unicode character scheme when presented with Unicode data--or
416          instead uses a traditional byte scheme when presented with byte
417          data.
419        Sadly, a wide octal escape does not cause a switch, and in a string with
420        no other multibyte characters, these octal escapes are treated as before.
421        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
422        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
423        Unicode string.
425        I have not perpetrated such confusion in PCRE. Up till now, it took just
426        the bottom 8 bits, as in old Perl. I have now made octal escapes with
427        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
428        translate to the appropriate multibyte character.
430    29. Applied some refactoring to reduce the number of warnings from Microsoft
431        and Borland compilers. This has included removing the fudge introduced
432        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
433        a warning about an unused variable.
435    21. PCRE has not included VT (character 0x0b) in the set of whitespace
436        characters since release 4.0, because Perl (from release 5.004) does not.
437        [Or at least, is documented not to: some releases seem to be in conflict
438        with the documentation.] However, when a pattern was studied with
439        pcre_study() and all its branches started with \s, PCRE still included VT
440        as a possible starting character. Of course, this did no harm; it just
441        caused an unnecessary match attempt.
443    22. Removed a now-redundant internal flag bit that recorded the fact that case
444        dependency changed within the pattern. This was once needed for "required
445        byte" processing, but is no longer used. This recovers a now-scarce options
446        bit. Also moved the least significant internal flag bit to the most-
447        significant bit of the word, which was not previously used (hangover from
448        the days when it was an int rather than a uint) to free up another bit for
449        the future.
451    23. Added support for CRLF line endings as well as CR and LF. As well as the
452        default being selectable at build time, it can now be changed at runtime
453        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
454        specify that it is scanning data with non-default line endings.
456    24. Changed the definition of CXXLINK to make it agree with the definition of
457        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
459    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
460        recursions. This makes a big different to stack usage for some patterns.
462    26. If a subpattern containing a named recursion or subroutine reference such
463        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
464        the space required for the compiled pattern went wrong and gave too small a
465        value. Depending on the environment, this could lead to "Failed: internal
466        error: code overflow at offset 49" or "glibc detected double free or
467        corruption" errors.
469    27. Applied patches from Google (a) to support the new newline modes and (b) to
470        advance over multibyte UTF-8 characters in GlobalReplace.
472    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
473        difference for some implementation of PCRE in some Windows version.
475    29. Added some extra testing facilities to pcretest:
477        \q<number>   in a data line sets the "match limit" value
478        \Q<number>   in a data line sets the "match recursion limt" value
479        -S <number>  sets the stack size, where <number> is in megabytes
481        The -S option isn't available for Windows.
484    Version 6.6 06-Feb-06
485    ---------------------
487     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
488        in pcreposix.h. I have copied the definition from pcre.h.
490     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
491        because pcre.h is no longer a built file.
493     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
494        not normally included in the compiled code.
497    Version 6.5 01-Feb-06
498    ---------------------
500     1. When using the partial match feature with pcre_dfa_exec(), it was not
501        anchoring the second and subsequent partial matches at the new starting
502        point. This could lead to incorrect results. For example, with the pattern
503        /1234/, partially matching against "123" and then "a4" gave a match.
505     2. Changes to pcregrep:
507        (a) All non-match returns from pcre_exec() were being treated as failures
508            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
509            error message is output. Some extra information is given for the
510            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
511            probably the only errors that are likely to be caused by users (by
512            specifying a regex that has nested indefinite repeats, for instance).
513            If there are more than 20 of these errors, pcregrep is abandoned.
515        (b) A binary zero was treated as data while matching, but terminated the
516            output line if it was written out. This has been fixed: binary zeroes
517            are now no different to any other data bytes.
519        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
520            used to set a locale for matching. The --locale=xxxx long option has
521            been added (no short equivalent) to specify a locale explicitly on the
522            pcregrep command, overriding the environment variables.
524        (d) When -B was used with -n, some line numbers in the output were one less
525            than they should have been.
527        (e) Added the -o (--only-matching) option.
529        (f) If -A or -C was used with -c (count only), some lines of context were
530            accidentally printed for the final match.
532        (g) Added the -H (--with-filename) option.
534        (h) The combination of options -rh failed to suppress file names for files
535            that were found from directory arguments.
537        (i) Added the -D (--devices) and -d (--directories) options.
539        (j) Added the -F (--fixed-strings) option.
541        (k) Allow "-" to be used as a file name for -f as well as for a data file.
543        (l) Added the --colo(u)r option.
545        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
546            is not present by default.
548     3. A nasty bug was discovered in the handling of recursive patterns, that is,
549        items such as (?R) or (?1), when the recursion could match a number of
550        alternatives. If it matched one of the alternatives, but subsequently,
551        outside the recursion, there was a failure, the code tried to back up into
552        the recursion. However, because of the way PCRE is implemented, this is not
553        possible, and the result was an incorrect result from the match.
555        In order to prevent this happening, the specification of recursion has
556        been changed so that all such subpatterns are automatically treated as
557        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
559     4. I had overlooked the fact that, in some locales, there are characters for
560        which isalpha() is true but neither isupper() nor islower() are true. In
561        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
562        and ordfeminine) are like this. This affected the treatment of \w and \W
563        when they appeared in character classes, but not when they appeared outside
564        a character class. The bit map for "word" characters is now created
565        separately from the results of isalnum() instead of just taking it from the
566        upper, lower, and digit maps. (Plus the underscore character, of course.)
568     5. The above bug also affected the handling of POSIX character classes such as
569        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
570        permanent tables. Instead, the bit maps for such a class were previously
571        created as the appropriate unions of the upper, lower, and digit bitmaps.
572        Now they are created by subtraction from the [[:word:]] class, which has
573        its own bitmap.
575     6. The [[:blank:]] character class matches horizontal, but not vertical space.
576        It is created by subtracting the vertical space characters (\x09, \x0a,
577        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
578        subtraction was done in the overall bitmap for a character class, meaning
579        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
580        be recognized. This bug has been fixed.
582     7. Patches from the folks at Google:
584          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
585          real life, but is still worth protecting against".
587          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
588          regular expressions".
590          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
591          have it.
593          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
594          "configure" and the latter not, in order to fix a problem somebody had
595          with compiling the Arg class on HP-UX.
597          (e) Improve the error-handling of the C++ wrapper a little bit.
599          (f) New tests for checking recursion limiting.
601     8. The pcre_memmove() function, which is used only if the environment does not
602        have a standard memmove() function (and is therefore rarely compiled),
603        contained two bugs: (a) use of int instead of size_t, and (b) it was not
604        returning a result (though PCRE never actually uses the result).
606     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
607        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
608        returned instead of calling malloc() with an overflowing number that would
609        most likely cause subsequent chaos.
611    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
613    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
614        with this option is matched, the nmatch and pmatch options of regexec() are
615        ignored.
617    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
618        provided in case anyone wants to the the POSIX interface with UTF-8
619        strings.
621    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
622        C++ linking (needed for some HP-UX environments).
624    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
625        (unused parameter) and in the pcre_printint() function (omitted "default"
626        switch label when the default is to do nothing).
628    15. Added some code to make it possible, when PCRE is compiled as a C++
629        library, to replace subject pointers for pcre_exec() with a smart pointer
630        class, thus making it possible to process discontinuous strings.
632    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
633        much the same function. They were added by different people who were trying
634        to make PCRE easy to compile on non-Unix systems. It has been suggested
635        that PCRE_EXPORT be abolished now that there is more automatic apparatus
636        for compiling on Windows systems. I have therefore replaced it with
637        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
638        defaults to "extern" for C or "extern C" for C++, which works fine on
639        Unix-like systems. It is now possible to override the value of PCRE_DATA_
640        SCOPE with something explicit in config.h. In addition:
642        (a) pcreposix.h still had just "extern" instead of either of these macros;
643            I have replaced it with PCRE_DATA_SCOPE.
645        (b) Functions such as _pcre_xclass(), which are internal to the library,
646            but external in the C sense, all had PCRE_EXPORT in their definitions.
647            This is apparently wrong for the Windows case, so I have removed it.
648            (It makes no difference on Unix-like systems.)
650    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
651        of recursive calls to match(). This is different to MATCH_LIMIT because
652        that limits the total number of calls to match(), not all of which increase
653        the depth of recursion. Limiting the recursion depth limits the amount of
654        stack (or heap if NO_RECURSE is set) that is used. The default can be set
655        when PCRE is compiled, and changed at run time. A patch from Google adds
656        this functionality to the C++ interface.
658    18. Changes to the handling of Unicode character properties:
660        (a) Updated the table to Unicode 4.1.0.
662        (b) Recognize characters that are not in the table as "Cn" (undefined).
664        (c) I revised the way the table is implemented to a much improved format
665            which includes recognition of ranges. It now supports the ranges that
666            are defined in UnicodeData.txt, and it also amalgamates other
667            characters into ranges. This has reduced the number of entries in the
668            table from around 16,000 to around 3,000, thus reducing its size
669            considerably. I realized I did not need to use a tree structure after
670            all - a binary chop search is just as efficient. Having reduced the
671            number of entries, I extended their size from 6 bytes to 8 bytes to
672            allow for more data.
674        (d) Added support for Unicode script names via properties such as \p{Han}.
676    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
677        matching that character.
679    20. When matching a repeated Unicode property with a minimum greater than zero,
680        (for example \pL{2,}), PCRE could look past the end of the subject if it
681        reached it while seeking the minimum number of characters. This could
682        happen only if some of the characters were more than one byte long, because
683        there is a check for at least the minimum number of bytes.
685    21. Refactored the implementation of \p and \P so as to be more general, to
686        allow for more different types of property in future. This has changed the
687        compiled form incompatibly. Anybody with saved compiled patterns that use
688        \p or \P will have to recompile them.
690    22. Added "Any" and "L&" to the supported property types.
692    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
693        but give a compile time error if the value is greater than 0xff.
695    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
696        accidentally not being installed or uninstalled.
698    25. The pcre.h file was built from pcre.h.in, but the only changes that were
699        made were to insert the current release number. This seemed silly, because
700        it made things harder for people building PCRE on systems that don't run
701        "configure". I have turned pcre.h into a distributed file, no longer built
702        by "configure", with the version identification directly included. There is
703        no longer a pcre.h.in file.
705        However, this change necessitated a change to the pcre-config script as
706        well. It is built from pcre-config.in, and one of the substitutions was the
707        release number. I have updated configure.ac so that ./configure now finds
708        the release number by grepping pcre.h.
710    26. Added the ability to run the tests under valgrind.
713    Version 6.4 05-Sep-05
714    ---------------------
716     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
717        "--" to be printed when multiple files were scanned, even when none of the
718        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
719        consider it to be a bug, and have restored the previous behaviour.
721     2. A couple of code tidies to get rid of compiler warnings.
723     3. The pcretest program used to cheat by referring to symbols in the library
724        whose names begin with _pcre_. These are internal symbols that are not
725        really supposed to be visible externally, and in some environments it is
726        possible to suppress them. The cheating is now confined to including
727        certain files from the library's source, which is a bit cleaner.
729     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
730        file's purpose clearer.
732     5. Reorganized pcre_ucp_findchar().
735    Version 6.3 15-Aug-05
736    ---------------------
738     1. The file libpcre.pc.in did not have general read permission in the tarball.
740     2. There were some problems when building without C++ support:
742        (a) If C++ support was not built, "make install" and "make test" still
743            tried to test it.
745        (b) There were problems when the value of CXX was explicitly set. Some
746            changes have been made to try to fix these, and ...
748        (c) --disable-cpp can now be used to explicitly disable C++ support.
750        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
751            backslash in a target when C++ was disabled. This confuses some
752            versions of "make", apparently. Using an intermediate variable solves
753            this. (Same for CPP_LOBJ.)
755     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
756        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
757        necessary on certain architectures.
759     4. Added a setting of -export-symbols-regex to the link command to remove
760        those symbols that are exported in the C sense, but actually are local
761        within the library, and not documented. Their names all begin with
762        "_pcre_". This is not a perfect job, because (a) we have to except some
763        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
764        available (and never for static libraries). I have made a note to try to
765        find a way round (a) in the future.
768    Version 6.2 01-Aug-05
769    ---------------------
771     1. There was no test for integer overflow of quantifier values. A construction
772        such as {1111111111111111} would give undefined results. What is worse, if
773        a minimum quantifier for a parenthesized subpattern overflowed and became
774        negative, the calculation of the memory size went wrong. This could have
775        led to memory overwriting.
777     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
779     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
780        operating environments where this matters.
782     4. Applied Giuseppe Maxia's patch to add additional features for controlling
783        PCRE options from within the C++ wrapper.
785     5. Named capturing subpatterns were not being correctly counted when a pattern
786        was compiled. This caused two problems: (a) If there were more than 100
787        such subpatterns, the calculation of the memory needed for the whole
788        compiled pattern went wrong, leading to an overflow error. (b) Numerical
789        back references of the form \12, where the number was greater than 9, were
790        not recognized as back references, even though there were sufficient
791        previous subpatterns.
793     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
794        versions of gcc, e.g. 2.95.4.
797    Version 6.1 21-Jun-05
798    ---------------------
800     1. There was one reference to the variable "posix" in pcretest.c that was not
801        surrounded by "#if !defined NOPOSIX".
803     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
804        the cross-check on the old pcre_info() function, for the benefit of the
805        cut-down version of PCRE that is currently imported into Exim.
807     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
808        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
809        patterns that start (?i) but I don't think that matters. The use of (?i) is
810        just an example; this all applies to the other options as well.
812     4. Since libtool seems to echo the compile commands it is issuing, the output
813        from "make" can be reduced a bit by putting "@" in front of each libtool
814        compile command.
816     5. Patch from the folks at Google for configure.in to be a bit more thorough
817        in checking for a suitable C++ installation before trying to compile the
818        C++ stuff. This should fix a reported problem when a compiler was present,
819        but no suitable headers.
821     6. The man pages all had just "PCRE" as their title. I have changed them to
822        be the relevant file name. I have also arranged that these names are
823        retained in the file doc/pcre.txt, which is a concatenation in text format
824        of all the man pages except the little individual ones for each function.
826     7. The NON-UNIX-USE file had not been updated for the different set of source
827        files that come with release 6. I also added a few comments about the C++
828        wrapper.
831    Version 6.0 07-Jun-05
832    ---------------------
834     1. Some minor internal re-organization to help with my DFA experiments.
836     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
837        didn't matter for the library itself when fully configured, but did matter
838        when compiling without UCP support, or within Exim, where the ucp files are
839        not imported.
841     3. Refactoring of the library code to split up the various functions into
842        different source modules. The addition of the new DFA matching code (see
843        below) to a single monolithic source would have made it really too
844        unwieldy, quite apart from causing all the code to be include in a
845        statically linked application, when only some functions are used. This is
846        relevant even without the DFA addition now that patterns can be compiled in
847        one application and matched in another.
849        The downside of splitting up is that there have to be some external
850        functions and data tables that are used internally in different modules of
851        the library but which are not part of the API. These have all had their
852        names changed to start with "_pcre_" so that they are unlikely to clash
853        with other external names.
855     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
856        a different (DFA) algorithm. Although it is slower than the original
857        function, it does have some advantages for certain types of matching
858        problem.
860     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
861        including restarting after a partial match.
863     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
864        defined when compiling for Windows was sent to me. I have put it into the
865        code, though I have no means of testing or verifying it.
867     7. Added the pcre_refcount() auxiliary function.
869     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
870        match before or at the first newline in the subject string. In pcretest,
871        the /f option on a pattern can be used to set this.
873     9. A repeated \w when used in UTF-8 mode with characters greater than 256
874        would behave wrongly. This has been present in PCRE since release 4.0.
876    10. A number of changes to the pcregrep command:
878        (a) Refactored how -x works; insert ^(...)$ instead of setting
879            PCRE_ANCHORED and checking the length, in preparation for adding
880            something similar for -w.
882        (b) Added the -w (match as a word) option.
884        (c) Refactored the way lines are read and buffered so as to have more
885            than one at a time available.
887        (d) Implemented a pcregrep test script.
889        (e) Added the -M (multiline match) option. This allows patterns to match
890            over several lines of the subject. The buffering ensures that at least
891            8K, or the rest of the document (whichever is the shorter) is available
892            for matching (and similarly the previous 8K for lookbehind assertions).
894        (f) Changed the --help output so that it now says
896              -w, --word-regex(p)
898            instead of two lines, one with "regex" and the other with "regexp"
899            because that confused at least one person since the short forms are the
900            same. (This required a bit of code, as the output is generated
901            automatically from a table. It wasn't just a text change.)
903        (g) -- can be used to terminate pcregrep options if the next thing isn't an
904            option but starts with a hyphen. Could be a pattern or a path name
905            starting with a hyphen, for instance.
907        (h) "-" can be given as a file name to represent stdin.
909        (i) When file names are being printed, "(standard input)" is used for
910            the standard input, for compatibility with GNU grep. Previously
911            "<stdin>" was used.
913        (j) The option --label=xxx can be used to supply a name to be used for
914            stdin when file names are being printed. There is no short form.
916        (k) Re-factored the options decoding logic because we are going to add
917            two more options that take data. Such options can now be given in four
918            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
920        (l) Added the -A, -B, and -C options for requesting that lines of context
921            around matches be printed.
923        (m) Added the -L option to print the names of files that do not contain
924            any matching lines, that is, the complement of -l.
926        (n) The return code is 2 if any file cannot be opened, but pcregrep does
927            continue to scan other files.
929        (o) The -s option was incorrectly implemented. For compatibility with other
930            greps, it now suppresses the error message for a non-existent or non-
931            accessible file (but not the return code). There is a new option called
932            -q that suppresses the output of matching lines, which was what -s was
933            previously doing.
935        (p) Added --include and --exclude options to specify files for inclusion
936            and exclusion when recursing.
938    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
939        Hopefully, it now does.
941    12. Missing cast in pcre_study().
943    13. Added an "uninstall" target to the makefile.
945    14. Replaced "extern" in the function prototypes in Makefile.in with
946        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
947        world, but is set differently for Windows.
949    15. Added a second compiling function called pcre_compile2(). The only
950        difference is that it has an extra argument, which is a pointer to an
951        integer error code. When there is a compile-time failure, this is set
952        non-zero, in addition to the error test pointer being set to point to an
953        error message. The new argument may be NULL if no error number is required
954        (but then you may as well call pcre_compile(), which is now just a
955        wrapper). This facility is provided because some applications need a
956        numeric error indication, but it has also enabled me to tidy up the way
957        compile-time errors are handled in the POSIX wrapper.
959    16. Added VPATH=.libs to the makefile; this should help when building with one
960        prefix path and installing with another. (Or so I'm told by someone who
961        knows more about this stuff than I do.)
963    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
964        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
965        match everything, including newlines. This is not POSIX-compatible, but
966        somebody wanted the feature. From pcretest it can be activated by using
967        both the P and the s flags.
969    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
971    19. libpcre.pc was being incorrectly installed as executable.
973    20. A couple of places in pcretest check for end-of-line by looking for '\n';
974        it now also looks for '\r' so that it will work unmodified on Windows.
976    21. Added Google's contributed C++ wrapper to the distribution.
978    22. Added some untidy missing memory free() calls in pcretest, to keep
979        Electric Fence happy when testing.
983    Version 5.0 13-Sep-04
984    ---------------------
986     1. Internal change: literal characters are no longer packed up into items
987        containing multiple characters in a single byte-string. Each character
988        is now matched using a separate opcode. However, there may be more than one
989        byte in the character in UTF-8 mode.
991     2. The pcre_callout_block structure has two new fields: pattern_position and
992        next_item_length. These contain the offset in the pattern to the next match
993        item, and its length, respectively.
995     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
996        insertion of callouts before each pattern item. Added the /C option to
997        pcretest to make use of this.
999     4. On the advice of a Windows user, the lines
1001          #if defined(_WIN32) || defined(WIN32)
1002          _setmode( _fileno( stdout ), 0x8000 );
1003          #endif  /* defined(_WIN32) || defined(WIN32) */
1005        have been added to the source of pcretest. This apparently does useful
1006        magic in relation to line terminators.
1008     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1009        for the benefit of those environments where the "b" makes a difference.
1011     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1012        to know about it. I have put a hack into configure.in that adds in code
1013        to set GCC=yes if CC=icc. This seems to end up at a point in the
1014        generated configure script that is early enough to affect the setting of
1015        compiler options, which is what is needed, but I have no means of testing
1016        whether it really works. (The user who reported this had patched the
1017        generated configure script, which of course I cannot do.)
1019        LATER: After change 22 below (new libtool files), the configure script
1020        seems to know about icc (and also ecc). Therefore, I have commented out
1021        this hack in configure.in.
1023     7. Added support for pkg-config (2 patches were sent in).
1025     8. Negated POSIX character classes that used a combination of internal tables
1026        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1027        [[:^ascii]]. Typically, they would match almost any characters. The other
1028        POSIX classes were not broken in this way.
1030     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1031        to find the match, as PCRE was deluded into thinking that the match had to
1032        start at the start point or following a newline. The same bug applied to
1033        patterns with negative forward assertions or any backward assertions
1034        preceding ".*" at the start, unless the pattern required a fixed first
1035        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1037    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1038        starting at the last subject character, bytes beyond the end of the subject
1039        string were read.
1041    11. Renamed the variable "class" as "classbits" to make life easier for C++
1042        users. (Previously there was a macro definition, but it apparently wasn't
1043        enough.)
1045    12. Added the new field "tables" to the extra data so that tables can be passed
1046        in at exec time, or the internal tables can be re-selected. This allows
1047        a compiled regex to be saved and re-used at a later time by a different
1048        program that might have everything at different addresses.
1050    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1051        -R library as well as a -L library.
1053    14. The debugging options of pcretest (-d on the command line or D on a
1054        pattern) showed incorrect output for anything following an extended class
1055        that contained multibyte characters and which was followed by a quantifier.
1057    15. Added optional support for general category Unicode character properties
1058        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1059        support. It adds about 90K to the size of the library. The meanings of the
1060        inbuilt class escapes such as \d and \s have NOT been changed.
1062    16. Updated pcredemo.c to include calls to free() to release the memory for the
1063        compiled pattern.
1065    17. The generated file chartables.c was being created in the source directory
1066        instead of in the building directory. This caused the build to fail if the
1067        source directory was different from the building directory, and was
1068        read-only.
1070    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1071        file. No doubt somebody will tell me if they don't make sense... Also added
1072        Dan Mooney's comments about building on OpenVMS.
1074    19. Added support for partial matching via the PCRE_PARTIAL option for
1075        pcre_exec() and the \P data escape in pcretest.
1077    20. Extended pcretest with 3 new pattern features:
1079        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1080              write the compiled pattern to the file whose name is "rest-of-line".
1081              This is a straight binary dump of the data, with the saved pointer to
1082              the character tables forced to be NULL. The study data, if any, is
1083              written too. After writing, pcretest reads a new pattern.
1085        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1086              compiled pattern from the given file. There must not be any
1087              occurrences of "<" in the file name (pretty unlikely); if there are,
1088              pcretest will instead treat the initial "<" as a pattern delimiter.
1089              After reading in the pattern, pcretest goes on to read data lines as
1090              usual.
1092        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1093              and 16-bit fields in a compiled pattern, to simulate a pattern that
1094              was compiled on a host of opposite endianness.
1096    21. The pcre-exec() function can now cope with patterns that were compiled on
1097        hosts of opposite endianness, with this restriction:
1099          As for any compiled expression that is saved and used later, the tables
1100          pointer field cannot be preserved; the extra_data field in the arguments
1101          to pcre_exec() should be used to pass in a tables address if a value
1102          other than the default internal tables were used at compile time.
1104    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1105        now diagnosed as an error. Previously, most of the time, a negative number
1106        would have been treated as zero, but if in addition "ovector" was passed as
1107        NULL, a crash could occur.
1109    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1110        new versions from the libtool 1.5 distribution (the last one is a copy of
1111        a file called libtool.m4). This seems to have fixed the need to patch
1112        "configure" to support Darwin 1.3 (which I used to do). However, I still
1113        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1114        workstation).
1116    24. Changed the PCRE licence to be the more standard "BSD" licence.
1119    Version 4.5 01-Dec-03
1120    ---------------------
1122     1. There has been some re-arrangement of the code for the match() function so
1123        that it can be compiled in a version that does not call itself recursively.
1124        Instead, it keeps those local variables that need separate instances for
1125        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1126        needs to "recurse". Keeping track of where control must go is done by means
1127        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1128        hide most of the details from the main code, and operates only if
1129        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1130        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1131        operating.
1133        To make it easier for callers to provide specially tailored get/free
1134        functions for this usage, two new functions, pcre_stack_malloc, and
1135        pcre_stack_free, are used. They are always called in strict stacking order,
1136        and the size of block requested is always the same.
1138        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1139        PCRE has been compiled to use the stack or the heap for recursion. The
1140        -C option of pcretest uses this to show which version is compiled.
1142        A new data escape \S, is added to pcretest; it causes the amounts of store
1143        obtained and freed by both kinds of malloc/free at match time to be added
1144        to the output.
1146     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1147        what's available on my current Linux desktop machine.
1149     3. When matching a UTF-8 string, the test for a valid string at the start has
1150        been extended. If start_offset is not zero, PCRE now checks that it points
1151        to a byte that is the start of a UTF-8 character. If not, it returns
1152        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1153        this is necessary because there may be backward assertions in the pattern.
1154        When matching the same subject several times, it may save resources to use
1155        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1157     4. The code for checking the validity of UTF-8 strings has been tightened so
1158        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1159        containing "overlong sequences".
1161     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1162        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1163        should have been "&", but it just so happened that all the cases this let
1164        through by mistake were picked up later in the function.
1166     6. I had used a variable called "isblank" - this is a C99 function, causing
1167        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1169     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1170        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1171        so the version is shown; (c) stop "make test" echoing "./RunTest".
1173     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1175     9. The prototype for memmove() for systems that don't have it was using
1176        size_t, but the inclusion of the header that defines size_t was later. I've
1177        moved the #includes for the C headers earlier to avoid this.
1179    10. Added some adjustments to the code to make it easier to compiler on certain
1180        special systems:
1182          (a) Some "const" qualifiers were missing.
1183          (b) Added the macro EXPORT before all exported functions; by default this
1184              is defined to be empty.
1185          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1186              that it reads its output file name as an argument instead of writing
1187              to the standard output and assuming this can be redirected.
1189    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1190        class containing characters with values greater than 255, PCRE compilation
1191        went into a loop.
1193    12. A recursive reference to a subpattern that was within another subpattern
1194        that had a minimum quantifier of zero caused PCRE to crash. For example,
1195        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1196        recursion. If the recursively-called subpattern itself had a zero repeat,
1197        that was OK.
1199    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1200        buffer into which it was copied (for escape processing) was still set at
1201        1024, so long lines caused crashes.
1203    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1204        "internal error: code overflow...". This applied to any character class
1205        that was followed by a possessive quantifier.
1207    15. Modified the Makefile to add libpcre.la as a prerequisite for
1208        libpcreposix.la because I was told this is needed for a parallel build to
1209        work.
1211    16. If a pattern that contained .* following optional items at the start was
1212        studied, the wrong optimizing data was generated, leading to matching
1213        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1214        matching string must start with a or b or c. The correct conclusion for
1215        this pattern is that a match can start with any character.
1218    Version 4.4 13-Aug-03
1219    ---------------------
1221     1. In UTF-8 mode, a character class containing characters with values between
1222        127 and 255 was not handled correctly if the compiled pattern was studied.
1223        In fixing this, I have also improved the studying algorithm for such
1224        classes (slightly).
1226     2. Three internal functions had redundant arguments passed to them. Removal
1227        might give a very teeny performance improvement.
1229     3. Documentation bug: the value of the capture_top field in a callout is *one
1230        more than* the number of the hightest numbered captured substring.
1232     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1233        in incorrectly linking with a previously installed version. They now link
1234        explicitly with libpcre.la.
1236     5. configure.in no longer needs to recognize Cygwin specially.
1238     6. A problem in pcre.in for Windows platforms is fixed.
1240     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1241        pcretest, it used to include the size of the study block as part of its
1242        output. Unfortunately, the structure contains a field that has a different
1243        size on different hardware architectures. This meant that the tests that
1244        showed this size failed. As the block is currently always of a fixed size,
1245        this information isn't actually particularly useful in pcretest output, so
1246        I have just removed it.
1248     8. Three pre-processor statements accidentally did not start in column 1.
1249        Sadly, there are *still* compilers around that complain, even though
1250        standard C has not required this for well over a decade. Sigh.
1252     9. In pcretest, the code for checking callouts passed small integers in the
1253        callout_data field, which is a void * field. However, some picky compilers
1254        complained about the casts involved for this on 64-bit systems. Now
1255        pcretest passes the address of the small integer instead, which should get
1256        rid of the warnings.
1258    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1259        both compile and run time, and gives an error if an invalid UTF-8 sequence
1260        is found. There is a option for disabling this check in cases where the
1261        string is known to be correct and/or the maximum performance is wanted.
1263    11. In response to a bug report, I changed one line in Makefile.in from
1265            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1266        to
1267            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1269        to look similar to other lines, but I have no way of telling whether this
1270        is the right thing to do, as I do not use Windows. No doubt I'll get told
1271        if it's wrong...
1274  Version 4.3 21-May-03  Version 4.3 21-May-03
1275  ---------------------  ---------------------

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