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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.02 01-Mar-2010
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
33    8.  Following on from 7, I added a similar kludge to check the length of the
34        eint vector in pcreposix.c.
36    9.  Error texts for pcre_compile() are held as one long string to avoid too
37        much relocation at load time. To find a text, the string is searched,
38        counting zeros. There was no check for running off the end of the string,
39        which could happen if a new error number was added without updating the
40        string.
42    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
44    11. \K was not working if it appeared in an atomic group or in a group that
45        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
46        \K is "not well defined" if used in an assertion. PCRE now accepts it if
47        the assertion is positive, but not if it is negative.
49    12. Change 11 fortuitously reduced the size of the stack frame used in the
50        "match()" function of pcre_exec.c by one pointer. Forthcoming
51        implementation of support for (*MARK) will need an extra pointer on the
52        stack; I have reserved it now, so that the stack frame size does not
53        decrease.
55    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
56        item in branch that calls a recursion is a subroutine call - as in the
57        second branch in the above example - was incorrectly given the compile-
58        time error "recursive call could loop indefinitely" because pcre_compile()
59        was not correctly checking the subroutine for matching a non-empty string.
62    Version 8.01 19-Jan-2010
63    ------------------------
65    1.  If a pattern contained a conditional subpattern with only one branch (in
66        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
67        computed the wrong minimum data length (which is of course zero for such
68        subpatterns). This could cause incorrect "no match" results.
70    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
71        the pattern is reset in the first branch, pcre_compile() failed with
72        "internal error: code overflow at offset...". This happened only when
73        the reset was to the original external option setting. (An optimization
74        abstracts leading options settings into an external setting, which was the
75        cause of this.)
77    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
78        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
79        assertion pattern did not match (meaning that the assertion was true), it
80        was incorrectly treated as false if the SKIP had been reached during the
81        matching. This also applied to assertions used as conditions.
83    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
84        assertion subpattern, including such a pattern used as a condition,
85        unpredictable results occurred, instead of the error return
88    5.  The C++ GlobalReplace function was not working like Perl for the special
89        situation when an empty string is matched. It now does the fancy magic
90        stuff that is necessary.
92    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
93        removed. (These were left over from very, very early versions of PCRE.)
95    7.  Some cosmetic changes to the code to make life easier when compiling it
96        as part of something else:
98        (a) Change DEBUG to PCRE_DEBUG.
100        (b) In pcre_compile(), rename the member of the "branch_chain" structure
101            called "current" as "current_branch", to prevent a collision with the
102            Linux macro when compiled as a kernel module.
104        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
105            prevent a collision with the Linux macro when compiled as a kernel
106            module.
108    8.  In pcre_compile() there are some checks for integer overflows that used to
109        cast potentially large values to (double). This has been changed to that
110        when building, a check for int64_t is made, and if it is found, it is used
111        instead, thus avoiding the use of floating point arithmetic. (There is no
112        other use of FP in PCRE.) If int64_t is not found, the fallback is to
113        double.
115    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
116        2005 (difference between two addresses compared to an unsigned value).
118    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
119        custom one, because of the following reported problem in Windows:
121          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
122              under Win32.
123          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
124              therefore missing the function definition.
125          - The compiler thus generates a "C" signature for the test function.
126          - The linker fails to find the "C" function.
127          - PCRE fails to configure if asked to do so against libbz2.
129    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
130        messages were output:
132          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
133          rerunning libtoolize, to keep the correct libtool macros in-tree.
134          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
136        I have done both of these things.
138    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
139        most of the time, it *can* run out if it is given a pattern that contains a
140        runaway infinite recursion. I updated the discussion in the pcrestack man
141        page.
143    13. Now that we have gone to the x.xx style of version numbers, the minor
144        version may start with zero. Using 08 or 09 is a bad idea because users
145        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
146        interpreted as invalid octal numbers. I've updated the previous comment in
147        configure.ac, and also added a check that gives an error if 08 or 09 are
148        used.
150    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
151        causing partial matching to fail when the end of the subject matched \W
152        in a UTF-8 pattern where \W was quantified with a minimum of 3.
154    15. There were some discrepancies between the declarations in pcre_internal.h
155        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
156        their definitions. The declarations used "const uschar *" and the
157        definitions used USPTR. Even though USPTR is normally defined as "const
158        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
159        reported that: "This difference in casting confuses some C++ compilers, for
160        example, SunCC recognizes above declarations as different functions and
161        generates broken code for hbpcre." I have changed the declarations to use
162        USPTR.
164    16. GNU libtool is named differently on some systems. The autogen.sh script now
165        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
166        (FreeBSD).
168    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
169        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
170        comment: "Figure out how to create a longlong from a string: strtoll and
171        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
172        instance, but it only takes 2 args instead of 3!"
174    18. A subtle bug concerned with back references has been fixed by a change of
175        specification, with a corresponding code fix. A pattern such as
176        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
177        refers, was giving matches when it shouldn't. For example, xa=xaaa would
178        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
179        same bug. Such groups have to be quantified to be useful, or contained
180        inside another quantified group. (If there's no repetition, the reference
181        can never match.) The problem arises because, having left the group and
182        moved on to the rest of the pattern, a later failure that backtracks into
183        the group uses the captured value from the final iteration of the group
184        rather than the correct earlier one. I have fixed this in PCRE by forcing
185        any group that contains a reference to itself to be an atomic group; that
186        is, there cannot be any backtracking into it once it has completed. This is
187        similar to recursive and subroutine calls.
190    Version 8.00 19-Oct-09
191    ----------------------
193    1.  The table for translating pcre_compile() error codes into POSIX error codes
194        was out-of-date, and there was no check on the pcre_compile() error code
195        being within the table. This could lead to an OK return being given in
196        error.
198    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
199        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
200        in a Windows environment.
202    3.  The pcregrep --count option prints the count for each file even when it is
203        zero, as does GNU grep. However, pcregrep was also printing all files when
204        --files-with-matches was added. Now, when both options are given, it prints
205        counts only for those files that have at least one match. (GNU grep just
206        prints the file name in this circumstance, but including the count seems
207        more useful - otherwise, why use --count?) Also ensured that the
208        combination -clh just lists non-zero counts, with no names.
210    4.  The long form of the pcregrep -F option was incorrectly implemented as
211        --fixed_strings instead of --fixed-strings. This is an incompatible change,
212        but it seems right to fix it, and I didn't think it was worth preserving
213        the old behaviour.
215    5.  The command line items --regex=pattern and --regexp=pattern were not
216        recognized by pcregrep, which required --regex pattern or --regexp pattern
217        (with a space rather than an '='). The man page documented the '=' forms,
218        which are compatible with GNU grep; these now work.
220    6.  No libpcreposix.pc file was created for pkg-config; there was just
221        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
223    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
224        when UCP support is not needed, by modifying the Python script that
225        generates it from Unicode data files. This should not matter if the module
226        is correctly used as a library, but I received one complaint about 50K of
227        unwanted data. My guess is that the person linked everything into his
228        program rather than using a library. Anyway, it does no harm.
230    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
231        was a minimum greater than 1 for a wide character in a possessive
232        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
233        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
234        character. Chaos in the form of incorrect output or a compiling loop could
235        result.
237    9.  The restrictions on what a pattern can contain when partial matching is
238        requested for pcre_exec() have been removed. All patterns can now be
239        partially matched by this function. In addition, if there are at least two
240        slots in the offset vector, the offset of the earliest inspected character
241        for the match and the offset of the end of the subject are set in them when
242        PCRE_ERROR_PARTIAL is returned.
244    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
245        synonymous with PCRE_PARTIAL, for backwards compatibility, and
246        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
247        and may be more useful for multi-segment matching.
249    11. Partial matching with pcre_exec() is now more intuitive. A partial match
250        used to be given if ever the end of the subject was reached; now it is
251        given only if matching could not proceed because another character was
252        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
253        string "Z", which now yields "no match" instead of "partial match". In the
254        case of pcre_dfa_exec(), "no match" is given if every matching path for the
255        final character ended with (*FAIL).
257    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
258        if the pattern had a "must contain" character that was already found in the
259        earlier partial match, unless partial matching was again requested. For
260        example, with the pattern /dog.(body)?/, the "must contain" character is
261        "g". If the first part-match was for the string "dog", restarting with
262        "sbody" failed. This bug has been fixed.
264    13. The string returned by pcre_dfa_exec() after a partial match has been
265        changed so that it starts at the first inspected character rather than the
266        first character of the match. This makes a difference only if the pattern
267        starts with a lookbehind assertion or \b or \B (\K is not supported by
268        pcre_dfa_exec()). It's an incompatible change, but it makes the two
269        matching functions compatible, and I think it's the right thing to do.
271    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
272        so that the demonstration program is easily available in environments where
273        PCRE has not been installed from source.
275    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
276        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
277        library.
279    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
280        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
281        is not the first non-POSIX option to be added. Clearly some people find
282        these options useful.
284    17. If a caller to the POSIX matching function regexec() passes a non-zero
285        value for nmatch with a NULL value for pmatch, the value of
286        nmatch is forced to zero.
288    18. RunGrepTest did not have a test for the availability of the -u option of
289        the diff command, as RunTest does. It now checks in the same way as
290        RunTest, and also checks for the -b option.
292    19. If an odd number of negated classes containing just a single character
293        interposed, within parentheses, between a forward reference to a named
294        subpattern and the definition of the subpattern, compilation crashed with
295        an internal error, complaining that it could not find the referenced
296        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
297        [The bug was that it was starting one character too far in when skipping
298        over the character class, thus treating the ] as data rather than
299        terminating the class. This meant it could skip too much.]
301    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
302        /g option in pcretest when the pattern contains \K, which makes it possible
303        to have an empty string match not at the start, even when the pattern is
304        anchored. Updated pcretest and pcredemo to use this option.
306    21. If the maximum number of capturing subpatterns in a recursion was greater
307        than the maximum at the outer level, the higher number was returned, but
308        with unset values at the outer level. The correct (outer level) value is
309        now given.
311    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
312        PCRE did not set those parentheses (unlike Perl). I have now found a way to
313        make it do so. The string so far is captured, making this feature
314        compatible with Perl.
316    23. The tests have been re-organized, adding tests 11 and 12, to make it
317        possible to check the Perl 5.10 features against Perl 5.10.
319    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
320        pattern matches a fixed length string. PCRE did not allow this; now it
321        does. Neither allows recursion.
323    25. I finally figured out how to implement a request to provide the minimum
324        length of subject string that was needed in order to match a given pattern.
325        (It was back references and recursion that I had previously got hung up
326        on.) This code has now been added to pcre_study(); it finds a lower bound
327        to the length of subject needed. It is not necessarily the greatest lower
328        bound, but using it to avoid searching strings that are too short does give
329        some useful speed-ups. The value is available to calling programs via
330        pcre_fullinfo().
332    26. While implementing 25, I discovered to my embarrassment that pcretest had
333        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
334        study optimizations had never been tested with that matching function.
335        Oops. What is worse, even when it was passed study data, there was a bug in
336        pcre_dfa_exec() that meant it never actually used it. Double oops. There
337        were also very few tests of studied patterns with pcre_dfa_exec().
339    27. If (?| is used to create subpatterns with duplicate numbers, they are now
340        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
341        on the other side of the coin, they are no longer allowed to have different
342        names, because these cannot be distinguished in PCRE, and this has caused
343        confusion. (This is a difference from Perl.)
345    28. When duplicate subpattern names are present (necessarily with different
346        numbers, as required by 27 above), and a test is made by name in a
347        conditional pattern, either for a subpattern having been matched, or for
348        recursion in such a pattern, all the associated numbered subpatterns are
349        tested, and the overall condition is true if the condition is true for any
350        one of them. This is the way Perl works, and is also more like the way
351        testing by number works.
354    Version 7.9 11-Apr-09
355    ---------------------
357    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
358        (pcretest), all targets were linked against these libraries. This included
359        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
360        libraries. This caused unwanted dependencies to be created. This problem
361        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
362        pcretest is linked with readline.
364    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
365        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
366        moved outside it again, because FALSE and TRUE are already defined in AIX,
367        but BOOL is not.
369    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
370        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
372    4.  The pcregrep documentation said spaces were inserted as well as colons (or
373        hyphens) following file names and line numbers when outputting matching
374        lines. This is not true; no spaces are inserted. I have also clarified the
375        wording for the --colour (or --color) option.
377    5.  In pcregrep, when --colour was used with -o, the list of matching strings
378        was not coloured; this is different to GNU grep, so I have changed it to be
379        the same.
381    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
382        each matching line was coloured. Now it goes on to look for further matches
383        of any of the test patterns, which is the same behaviour as GNU grep.
385    7.  A pattern that could match an empty string could cause pcregrep to loop; it
386        doesn't make sense to accept an empty string match in pcregrep, so I have
387        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
388        seems to be how GNU grep behaves.
390    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
391        start or after a newline", because the conditional assertion was not being
392        correctly handled. The rule now is that both the assertion and what follows
393        in the first alternative must satisfy the test.
395    9.  If auto-callout was enabled in a pattern with a conditional group whose
396        condition was an assertion, PCRE could crash during matching, both with
397        pcre_exec() and pcre_dfa_exec().
399    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
400        used for matching.
402    11. Unicode property support in character classes was not working for
403        characters (bytes) greater than 127 when not in UTF-8 mode.
405    12. Added the -M command line option to pcretest.
407    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
409    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
411    16. Added comments and documentation about mis-use of no_arg in the C++
412        wrapper.
414    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
415        from Martin Jerabek that uses macro names for all relevant character and
416        string constants.
418    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
419        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
420        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
421        these, but not everybody uses configure.
423    19. A conditional group that had only one branch was not being correctly
424        recognized as an item that could match an empty string. This meant that an
425        enclosing group might also not be so recognized, causing infinite looping
426        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
427        with the subject "ab", where knowledge that the repeated group can match
428        nothing is needed in order to break the loop.
430    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
431        exec(), but without supplying a callout function, matching went wrong.
433    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
434        leak if the size of the offset vector was greater than 30. When the vector
435        is smaller, the saved offsets during recursion go onto a local stack
436        vector, but for larger vectors malloc() is used. It was failing to free
437        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
438        error, in fact).
440    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
441        heapframe that is used only when UTF-8 support is enabled. This caused no
442        problem, but was untidy.
444    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
445        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
446        included within another project.
448    24. Steven Van Ingelgem's patches to add more options to the CMake support,
449        slightly modified by me:
451          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
452              not building pcregrep.
454          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
455              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
457    25. Forward references, both numeric and by name, in patterns that made use of
458        duplicate group numbers, could behave incorrectly or give incorrect errors,
459        because when scanning forward to find the reference group, PCRE was not
460        taking into account the duplicate group numbers. A pattern such as
461        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
463    26. Changed a few more instances of "const unsigned char *" to USPTR, making
464        the feature of a custom pointer more persuasive (as requested by a user).
466    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
467        pcretest.c, inside #ifndefs, because it seems they are sometimes already
468        pre-defined.
470    28. Added support for (*UTF8) at the start of a pattern.
472    29. Arrange for flags added by the "release type" setting in CMake to be shown
473        in the configuration summary.
476    Version 7.8 05-Sep-08
477    ---------------------
479    1.  Replaced UCP searching code with optimized version as implemented for Ad
480        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
481        stage table and inline lookup instead of a function, giving speed ups of 2
482        to 5 times on some simple patterns that I tested. Permission was given to
483        distribute the MultiStage2.py script that generates the tables (it's not in
484        the tarball, but is in the Subversion repository).
486    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
487        scripts.
489    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
490        a group with a zero qualifier. The result of the study could be incorrect,
491        or the function might crash, depending on the pattern.
493    4.  Caseless matching was not working for non-ASCII characters in back
494        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
495        It now works when Unicode Property Support is available.
497    5.  In pcretest, an escape such as \x{de} in the data was always generating
498        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
499        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
500        truncation.
502    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
504    7.  Added two (int) casts to pcregrep when printing the difference of two
505        pointers, in case they are 64-bit values.
507    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
508        test 2 if it fails.
510    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
511        and a #define of that name to empty if it is not externally set. This is to
512        allow users of MSVC to set it if necessary.
514    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
515        the convenience functions in the pcre_get.c source file.
517    11. An option change at the start of a pattern that had top-level alternatives
518        could cause overwriting and/or a crash. This command provoked a crash in
519        some environments:
521          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
523        This potential security problem was recorded as CVE-2008-2371.
525    12. For a pattern where the match had to start at the beginning or immediately
526        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
527        pcre_dfa_exec() could read past the end of the passed subject if there was
528        no match. To help with detecting such bugs (e.g. with valgrind), I modified
529        pcretest so that it places the subject at the end of its malloc-ed buffer.
531    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
532        exec() might read past the end of the data buffer in UTF-8 mode.
534    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
535        the data contained the byte 0x85 as part of a UTF-8 character within its
536        first line. This applied both to normal and DFA matching.
538    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
539        /^[^d]*?$/8 failed to match "abc".
541    16. Added a missing copyright notice to pcrecpp_internal.h.
543    17. Make it more clear in the documentation that values returned from
544        pcre_exec() in ovector are byte offsets, not character counts.
546    18. Tidied a few places to stop certain compilers from issuing warnings.
548    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
549        supplied by Stefan Weber. I made a further small update for 7.8 because
550        there is a change of source arrangements: the pcre_searchfuncs.c module is
551        replaced by pcre_ucd.c.
554    Version 7.7 07-May-08
555    ---------------------
557    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
558        a string to a long long, pretend we don't even have a long long." This is
559        done by checking for the strtoq, strtoll, and _strtoi64 functions.
561    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
562        pre-7.6 versions, which defined a global no_arg variable instead of putting
563        it in the RE class. (See also #8 below.)
565    3.  Remove a line of dead code, identified by coverity and reported by Nuno
566        Lopes.
568    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
570        (1) The include/exclude patterns were being applied to the whole pathnames
571            of files, instead of just to the final components.
573        (2) If there was more than one level of directory, the subdirectories were
574            skipped unless they satisfied the include/exclude conditions. This is
575            inconsistent with GNU grep (and could even be seen as contrary to the
576            pcregrep specification - which I improved to make it absolutely clear).
577            The action now is always to scan all levels of directory, and just
578            apply the include/exclude patterns to regular files.
580    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
581        --exclude_dir in the tests to avoid scanning .svn directories.
583    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
584        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
585        doesn't support NULs in patterns.
587    7.  Added some missing "const"s to declarations of static tables in
588        pcre_compile.c and pcre_dfa_exec.c.
590    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
591        caused by fix #2  above. (Subsequently also a second patch to fix the
592        first patch. And a third patch - this was a messy problem.)
594    9.  Applied Craig's patch to remove the use of push_back().
596    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
597        matching function regexec().
599    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
600        which, however, unlike Perl's \g{...}, are subroutine calls, not back
601        references. PCRE supports relative numbers with this syntax (I don't think
602        Oniguruma does).
604    12. Previously, a group with a zero repeat such as (...){0} was completely
605        omitted from the compiled regex. However, this means that if the group
606        was called as a subroutine from elsewhere in the pattern, things went wrong
607        (an internal error was given). Such groups are now left in the compiled
608        pattern, with a new opcode that causes them to be skipped at execution
609        time.
611    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
612        to the way PCRE behaves:
614        (a) A lone ] character is dis-allowed (Perl treats it as data).
616        (b) A back reference to an unmatched subpattern matches an empty string
617            (Perl fails the current match path).
619        (c) A data ] in a character class must be notated as \] because if the
620            first data character in a class is ], it defines an empty class. (In
621            Perl it is not possible to have an empty class.) The empty class []
622            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
623            The negative empty class [^] matches any one character, independently
624            of the DOTALL setting.
626    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
627        non-existent subpattern following a character class starting with ']' and
628        containing () gave an internal compiling error instead of "reference to
629        non-existent subpattern". Fortunately, when the pattern did exist, the
630        compiled code was correct. (When scanning forwards to check for the
631        existencd of the subpattern, it was treating the data ']' as terminating
632        the class, so got the count wrong. When actually compiling, the reference
633        was subsequently set up correctly.)
635    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
636        it was being rejected as not supported by pcre_dfa_exec(), even though
637        other assertions are supported. I have made pcre_dfa_exec() support
638        (*FAIL).
640    16. The implementation of 13c above involved the invention of a new opcode,
641        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
642        cannot be changed at match time, I realized I could make a small
643        improvement to matching performance by compiling OP_ALLANY instead of
644        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
645        on the OP_ANY path.
647    17. Compiling pcretest on Windows with readline support failed without the
648        following two fixes: (1) Make the unistd.h include conditional on
649        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
651    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
652        ncurses library to be included for pcretest when ReadLine support is
653        requested, but also to allow for it to be overridden. This patch came from
654        Daniel Bergström.
656    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
657        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
658        any errors with the current Unicode tables. Thanks to Peter Kankowski for
659        spotting this.
662    Version 7.6 28-Jan-08
663    ---------------------
665    1.  A character class containing a very large number of characters with
666        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
667        overflow.
669    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
670        HAVE_LONG_LONG is not defined.
672    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
673        bring them up to date and include new features. This patch includes:
675        - Fixed PH's badly added libz and libbz2 support.
676        - Fixed a problem with static linking.
677        - Added pcredemo. [But later removed - see 7 below.]
678        - Fixed dftables problem and added an option.
679        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
680            HAVE_LONG_LONG.
681        - Added readline support for pcretest.
682        - Added an listing of the option settings after cmake has run.
684    4.  A user submitted a patch to Makefile that makes it easy to create
685        "pcre.dll" under mingw when using Configure/Make. I added stuff to
686        Makefile.am that cause it to include this special target, without
687        affecting anything else. Note that the same mingw target plus all
688        the other distribution libraries and programs are now supported
689        when configuring with CMake (see 6 below) instead of with
690        Configure/Make.
692    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
693        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
694        exported in the Windows port". It has not yet been confirmed that the patch
695        solves the problem, but it does no harm.
697    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
698        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
699        with CMake, and also correct the comment about stack recursion.
701    7.  Remove the automatic building of pcredemo from the ./configure system and
702        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
703        of a program that users should build themselves after PCRE is installed, so
704        building it automatically is not really right. What is more, it gave
705        trouble in some build environments.
707    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
710    Version 7.5 10-Jan-08
711    ---------------------
713    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
714        values in parens when parsing an RE using the C++ wrapper."
716    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
717        Characters greater than 255 were excluded from the class instead of being
718        included.
720    3.  The same bug as (2) above applied to negated POSIX classes such as
721        [:^space:].
723    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
724        defined or documented. It seems to have been a typo for PCRE_STATIC, so
725        I have changed it.
727    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
728        first named subpattern) and a construct such as (?&a) would reference the
729        first named subpattern whose name started with "a" (in other words, the
730        length check was missing). Both these problems are fixed. "Subpattern name
731        expected" is now given for (?&) (a zero-length name), and this patch also
732        makes it give the same error for \k'' (previously it complained that that
733        was a reference to a non-existent subpattern).
735    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
736        this is right because (?- can be followed by option settings as well as by
737        digits. I have, however, made the messages clearer.
739    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
740        than the number used in the conditional) now cause a compile-time error.
741        This is actually not compatible with Perl, which accepts such patterns, but
742        treats the conditional as always being FALSE (as PCRE used to), but it
743        seems to me that giving a diagnostic is better.
745    8.  Change "alphameric" to the more common word "alphanumeric" in comments
746        and messages.
748    9.  Fix two occurrences of "backslash" in comments that should have been
749        "backspace".
751    10. Remove two redundant lines of code that can never be obeyed (their function
752        was moved elsewhere).
754    11. The program that makes PCRE's Unicode character property table had a bug
755        which caused it to generate incorrect table entries for sequences of
756        characters that have the same character type, but are in different scripts.
757        It amalgamated them into a single range, with the script of the first of
758        them. In other words, some characters were in the wrong script. There were
759        thirteen such cases, affecting characters in the following ranges:
761          U+002b0 - U+002c1
762          U+0060c - U+0060d
763          U+0061e - U+00612
764          U+0064b - U+0065e
765          U+0074d - U+0076d
766          U+01800 - U+01805
767          U+01d00 - U+01d77
768          U+01d9b - U+01dbf
769          U+0200b - U+0200f
770          U+030fc - U+030fe
771          U+03260 - U+0327f
772          U+0fb46 - U+0fbb1
773          U+10450 - U+1049d
775    12. The -o option (show only the matching part of a line) for pcregrep was not
776        compatible with GNU grep in that, if there was more than one match in a
777        line, it showed only the first of them. It now behaves in the same way as
778        GNU grep.
780    13. If the -o and -v options were combined for pcregrep, it printed a blank
781        line for every non-matching line. GNU grep prints nothing, and pcregrep now
782        does the same. The return code can be used to tell if there were any
783        non-matching lines.
785    14. Added --file-offsets and --line-offsets to pcregrep.
787    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
788        infinitely looping recursion. The bug was that positive lookaheads were not
789        being skipped when checking for a possible empty match (negative lookaheads
790        and both kinds of lookbehind were skipped).
792    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
793        inclusion of <windows.h> to before rather than after the definition of
794        INVALID_FILE_ATTRIBUTES (patch from David Byron).
796    17. Specifying a possessive quantifier with a specific limit for a Unicode
797        character property caused pcre_compile() to compile bad code, which led at
798        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
799        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
800        caused the error; without that there was no problem.
802    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
804    19. Added --enable-pcretest-libreadline.
806    20. In pcrecpp.cc, the variable 'count' was incremented twice in
807        RE::GlobalReplace(). As a result, the number of replacements returned was
808        double what it should be. I removed one of the increments, but Craig sent a
809        later patch that removed the other one (the right fix) and added unit tests
810        that check the return values (which was not done before).
812    21. Several CMake things:
814        (1) Arranged that, when cmake is used on Unix, the libraries end up with
815            the names libpcre and libpcreposix, not just pcre and pcreposix.
817        (2) The above change means that pcretest and pcregrep are now correctly
818            linked with the newly-built libraries, not previously installed ones.
822    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
823        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
824        UTF-8 newline character). The key issue is that the pattern starts .*;
825        this means that the match must be either at the beginning, or after a
826        newline. The bug was in the code for advancing after a failed match and
827        checking that the new position followed a newline. It was not taking
828        account of UTF-8 characters correctly.
830    23. PCRE was behaving differently from Perl in the way it recognized POSIX
831        character classes. PCRE was not treating the sequence [:...:] as a
832        character class unless the ... were all letters. Perl, however, seems to
833        allow any characters between [: and :], though of course it rejects as
834        unknown any "names" that contain non-letters, because all the known class
835        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
836        for example, whereas PCRE did not - it did not recognize a POSIX character
837        class. This seemed a bit dangerous, so the code has been changed to be
838        closer to Perl. The behaviour is not identical to Perl, because PCRE will
839        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
840        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
841        Perl does, and where it didn't before.
843    24. Rewrite so as to remove the single use of %n from pcregrep because in some
844        Windows environments %n is disabled by default.
847    Version 7.4 21-Sep-07
848    ---------------------
850    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
851        means that a class such as [\s] counted as "explicit reference to CR or
852        LF". That isn't really right - the whole point of the change was to try to
853        help when there was an actual mention of one of the two characters. So now
854        the change happens only if \r or \n (or a literal CR or LF) character is
855        encountered.
857    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
858        of both had grown to the point where there were only 3 bits left.
859        Fortunately, there was spare space in the data structure, and so I have
860        moved the internal flags into a new 16-bit field to free up more option
861        bits.
863    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
864        but did not set the internal JCHANGED flag - either of these is enough to
865        control the way the "get" function works - but the PCRE_INFO_JCHANGED
866        facility is supposed to tell if (?J) was ever used, so now (?J) at the
867        start sets both bits.
869    4.  Added options (at build time, compile time, exec time) to change \R from
870        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
872    5.  doc/pcresyntax.html was missing from the distribution.
874    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
875        compatibility, even though it is no longer used.
877    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
878        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
879        windows.h file is present (where different names are used). [This was
880        reversed later after testing - see 16 below.]
882    8.  Changed all #include <config.h> to #include "config.h". There were also
883        some further <pcre.h> cases that I changed to "pcre.h".
885    9.  When pcregrep was used with the --colour option, it missed the line ending
886        sequence off the lines that it output.
888    10. It was pointed out to me that arrays of string pointers cause lots of
889        relocations when a shared library is dynamically loaded. A technique of
890        using a single long string with a table of offsets can drastically reduce
891        these. I have refactored PCRE in four places to do this. The result is
892        dramatic:
894          Originally:                          290
895          After changing UCP table:            187
896          After changing error message table:   43
897          After changing table of "verbs"       36
898          After changing table of Posix names   22
900        Thanks to the folks working on Gregex for glib for this insight.
902    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
903        unicode-properties was also set.
905    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
907    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
908        checked only for CRLF.
910    14. Added casts to pcretest.c to avoid compiler warnings.
912    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
914    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
915        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
916        entirely. This removes changes made in 7 above.
918    17. The CMake files have been updated, and there is now more information about
919        building with CMake in the NON-UNIX-USE document.
922    Version 7.3 28-Aug-07
923    ---------------------
925     1. In the rejigging of the build system that eventually resulted in 7.1, the
926        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
927        brackets there is not right, since it causes compilers to look for an
928        installed pcre.h, not the version that is in the source that is being
929        compiled (which of course may be different). I have changed it back to:
931          #include "pcre.h"
933        I have a vague recollection that the change was concerned with compiling in
934        different directories, but in the new build system, that is taken care of
935        by the VPATH setting the Makefile.
937     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
938        when the subject happened to end in the byte 0x85 (e.g. if the last
939        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
940        characters but of course it shouldn't be taken as a newline when it is part
941        of another character. The bug was that, for an unlimited repeat of . in
942        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
943        characters when looking for a newline.
945     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
947     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
948        in debug output.
950     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
951        long printing in the pcrecpp unittest when running under MinGW.
953     6. ESC_K was left out of the EBCDIC table.
955     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
956        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
957        limit also applies to "virtual nesting" when a pattern is recursive, and in
958        this case 1000 isn't so big. I have been able to remove this limit at the
959        expense of backing off one optimization in certain circumstances. Normally,
960        when pcre_exec() would call its internal match() function recursively and
961        immediately return the result unconditionally, it uses a "tail recursion"
962        feature to save stack. However, when a subpattern that can match an empty
963        string has an unlimited repetition quantifier, it no longer makes this
964        optimization. That gives it a stack frame in which to save the data for
965        checking that an empty string has been matched. Previously this was taken
966        from the 1000-entry workspace that had been reserved. So now there is no
967        explicit limit, but more stack is used.
969     8. Applied Daniel's patches to solve problems with the import/export magic
970        syntax that is required for Windows, and which was going wrong for the
971        pcreposix and pcrecpp parts of the library. These were overlooked when this
972        problem was solved for the main library.
974     9. There were some crude static tests to avoid integer overflow when computing
975        the size of patterns that contain repeated groups with explicit upper
976        limits. As the maximum quantifier is 65535, the maximum group length was
977        set at 30,000 so that the product of these two numbers did not overflow a
978        32-bit integer. However, it turns out that people want to use groups that
979        are longer than 30,000 bytes (though not repeat them that many times).
980        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
981        made it possible to implement the integer overflow checks in a much more
982        dynamic way, which I have now done. The artificial limitation on group
983        length has been removed - we now have only the limit on the total length of
984        the compiled pattern, which depends on the LINK_SIZE setting.
986    10. Fixed a bug in the documentation for get/copy named substring when
987        duplicate names are permitted. If none of the named substrings are set, the
988        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
989        empty string.
991    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
992        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
993        because the ] is interpreted as the first data character and the
994        terminating ] is not found. PCRE has been made compatible with Perl in this
995        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
996        cause memory overwriting.
998    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
999        string has been matched (to stop an infinite loop). It was not recognizing
1000        a conditional subpattern that could match an empty string if that
1001        subpattern was within another subpattern. For example, it looped when
1002        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1003        condition was not nested. This bug has been fixed.
1005    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1006        past the start of the subject in the presence of bytes with the top bit
1007        set, for example "\x8aBCD".
1009    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1010        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1012    14. Optimized (?!) to (*FAIL).
1014    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1015        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1016        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1017        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1018        does: it's just the validity check that is more restrictive.
1020    16. Inserted checks for integer overflows during escape sequence (backslash)
1021        processing, and also fixed erroneous offset values for syntax errors during
1022        backslash processing.
1024    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1025        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1027    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1028        caused an overrun.
1030    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1031        something other than just ASCII characters) inside a group that had an
1032        unlimited repeat caused a loop at compile time (while checking to see
1033        whether the group could match an empty string).
1035    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1036        [\P{Any}] did so. (Error in the code for printing property names.)
1038    21. An orphan \E inside a character class could cause a crash.
1040    22. A repeated capturing bracket such as (A)? could cause a wild memory
1041        reference during compilation.
1043    23. There are several functions in pcre_compile() that scan along a compiled
1044        expression for various reasons (e.g. to see if it's fixed length for look
1045        behind). There were bugs in these functions when a repeated \p or \P was
1046        present in the pattern. These operators have additional parameters compared
1047        with \d, etc, and these were not being taken into account when moving along
1048        the compiled data. Specifically:
1050        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1051            length.
1053        (b) An item such as \pL+ within a repeated group could cause crashes or
1054            loops.
1056        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1057            "reference to non-existent subpattern" error.
1059        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1061    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1062        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1064    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1066    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1067        character were causing crashes (broken optimization).
1069    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1070        \p or \P) caused a compile-time loop.
1072    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1073        break. For example, the unstudied pattern [\r\n]A does not match the string
1074        "\r\nA" because change 7.0/46 below moves the current point on by two
1075        characters after failing to match at the start. However, the pattern \nA
1076        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1077        the same is true. There doesn't seem any very clean way out of this, but
1078        what I have chosen to do makes the common cases work: PCRE now takes note
1079        of whether there can be an explicit match for \r or \n anywhere in the
1080        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1081        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1082        pattern has explicit CR or LF references.
1084    29. Added (*CR) etc for changing newline setting at start of pattern.
1087    Version 7.2 19-Jun-07
1088    ---------------------
1090     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1091        which is apparently normally available under Windows.
1093     2. Re-jig the pcregrep tests with different newline settings in an attempt
1094        to make them independent of the local environment's newline setting.
1096     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1098     4. Some of the "internals" tests were previously cut out when the link size
1099        was not 2, because the output contained actual offsets. The recent new
1100        "Z" feature of pcretest means that these can be cut out, making the tests
1101        usable with all link sizes.
1103     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1104        stack recursion. This gives a massive performance boost under BSD, but just
1105        a small improvement under Linux. However, it saves one field in the frame
1106        in all cases.
1108     6. Added more features from the forthcoming Perl 5.10:
1110        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1111            recursion call. It refers to the nth most recently opened parentheses.
1113        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1114            to be opened parentheses.
1116        (c) Conditions that refer to capturing parentheses can be specified
1117            relatively, for example, (?(-2)... or (?(+3)...
1119        (d) \K resets the start of the current match so that everything before
1120            is not part of it.
1122        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1124        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1125            reference syntax.
1127        (g) (?| introduces a group in which the numbering of parentheses in each
1128            alternative starts with the same number.
1130        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1132     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1135     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1136        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1137        for detecting groups that can match an empty string.
1139     9. A pattern with a very large number of alternatives (more than several
1140        hundred) was running out of internal workspace during the pre-compile
1141        phase, where pcre_compile() figures out how much memory will be needed. A
1142        bit of new cunning has reduced the workspace needed for groups with
1143        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1144        workspace instead of running out of the 4096 that are available.
1146    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1148    11. Applied patch from Google to remove an optimization that didn't quite work.
1149        The report of the bug said:
1151          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1152          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1153          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1155    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1156        it matched the wrong number of bytes.
1159    Version 7.1 24-Apr-07
1160    ---------------------
1162     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1163        that is more "standard", making use of automake and other Autotools. There
1164        is some re-arrangement of the files and adjustment of comments consequent
1165        on this.
1167     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1168        for recursive directory scanning broke on some systems because the files
1169        are not scanned in any specific order and on different systems the order
1170        was different. A call to "sort" has been inserted into RunGrepTest for the
1171        approprate test as a short-term fix. In the longer term there may be an
1172        alternative.
1174     3. I had an email from Eric Raymond about problems translating some of PCRE's
1175        man pages to HTML (despite the fact that I distribute HTML pages, some
1176        people do their own conversions for various reasons). The problems
1177        concerned the use of low-level troff macros .br and .in. I have therefore
1178        removed all such uses from the man pages (some were redundant, some could
1179        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1180        HTML has been updated to handle .nf/.fi and to complain if it encounters
1181        .br or .in.
1183     4. Updated comments in configure.ac that get placed in config.h.in and also
1184        arranged for config.h to be included in the distribution, with the name
1185        config.h.generic, for the benefit of those who have to compile without
1186        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1188     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1189        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1190        makevp.bat for the current PCRE, using the additional files
1191        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1193     6. A Windows user reported a minor discrepancy with test 2, which turned out
1194        to be caused by a trailing space on an input line that had got lost in his
1195        copy. The trailing space was an accident, so I've just removed it.
1197     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1198        that is needed.
1200     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1201        as "const" (a) because they are and (b) because it helps the PHP
1202        maintainers who have recently made a script to detect big data structures
1203        in the php code that should be moved to the .rodata section. I remembered
1204        to update Builducptable as well, so it won't revert if ucptable.h is ever
1205        re-created.
1207     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1208        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1209        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1210        support is not required. This saves 1.5-2K of code, which is important in
1211        some applications.
1213        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1214        so as not to refer to the tables, even though these functions will never be
1215        called when UTF-8 support is disabled. Otherwise there are problems with a
1216        shared library.
1218    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1220        (a) It was defining its arguments as char * instead of void *.
1222        (b) It was assuming that all moves were upwards in memory; this was true
1223            a long time ago when I wrote it, but is no longer the case.
1225        The emulated memove() is provided for those environments that have neither
1226        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1227        is clearly not the case, as these two bugs were recently reported.
1229    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1230        and Detrail to create the HTML documentation, the .txt form of the man
1231        pages, and it removes trailing spaces from listed files. It also creates
1232        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1233        case, it wraps all the #defines with #ifndefs. This script should be run
1234        before "make dist".
1236    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1237        with Unicode property support.
1239        (a) For a maximizing quantifier, if the two different cases of the
1240            character were of different lengths in their UTF-8 codings (there are
1241            some cases like this - I found 11), and the matching function had to
1242            back up over a mixture of the two cases, it incorrectly assumed they
1243            were both the same length.
1245        (b) When PCRE was configured to use the heap rather than the stack for
1246            recursion during matching, it was not correctly preserving the data for
1247            the other case of a UTF-8 character when checking ahead for a match
1248            while processing a minimizing repeat. If the check also involved
1249            matching a wide character, but failed, corruption could cause an
1250            erroneous result when trying to check for a repeat of the original
1251            character.
1253    13. Some tidying changes to the testing mechanism:
1255        (a) The RunTest script now detects the internal link size and whether there
1256            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1257            values substituted by "configure". (The RunGrepTest script already did
1258            this for UTF-8.) The configure.ac script no longer substitutes the
1259            relevant variables.
1261        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1262            with length and offset values. This means that the output is different
1263            for different internal link sizes. Test 2 is skipped for link sizes
1264            other than 2 because of this, bypassing the problem. Unfortunately,
1265            there was also a test in test 3 (the locale tests) that used /B and
1266            failed for link sizes other than 2. Rather than cut the whole test out,
1267            I have added a new /Z option to pcretest that replaces the length and
1268            offset values with spaces. This is now used to make test 3 independent
1269            of link size. (Test 2 will be tidied up later.)
1271    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1272        segmentation fault instead of returning the appropriate error message.
1274    15. In multiline mode when the newline sequence was set to "any", the pattern
1275        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1276        This doesn't seem right; it now treats the CRLF combination as the line
1277        ending, and so does not match in that case. It's only a pattern such as ^$
1278        that would hit this one: something like ^ABC$ would have failed after \r
1279        and then tried again after \r\n.
1281    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1282        in an attempt to make files that differ only in their line terminators
1283        compare equal. This works on Linux.
1285    17. Under certain error circumstances pcregrep might try to free random memory
1286        as it exited. This is now fixed, thanks to valgrind.
1288    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1289        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1290        was because its rules for how to advance for /g after matching an empty
1291        string at the end of a line did not allow for this case. They now check for
1292        it specially.
1294    20. pcretest is supposed to handle patterns and data of any length, by
1295        extending its buffers when necessary. It was getting this wrong when the
1296        buffer for a data line had to be extended.
1298    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1299        CRLF as a newline sequence.
1301    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1302        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1303        I have nevertheless tidied it up.
1305    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1307    24. Added a man page for pcre-config.
1310    Version 7.0 19-Dec-06
1311    ---------------------
1313     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1314        moving to gcc 4.1.1.
1316     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1317        sys/time.h, which is documented as needed for this function. It doesn't
1318        seem to matter on Linux, but it showed up on some releases of OS X.
1320     3. It seems that there are systems where bytes whose values are greater than
1321        127 match isprint() in the "C" locale. The "C" locale should be the
1322        default when a C program starts up. In most systems, only ASCII printing
1323        characters match isprint(). This difference caused the output from pcretest
1324        to vary, making some of the tests fail. I have changed pcretest so that:
1326        (a) When it is outputting text in the compiled version of a pattern, bytes
1327            other than 32-126 are always shown as hex escapes.
1329        (b) When it is outputting text that is a matched part of a subject string,
1330            it does the same, unless a different locale has been set for the match
1331            (using the /L modifier). In this case, it uses isprint() to decide.
1333     4. Fixed a major bug that caused incorrect computation of the amount of memory
1334        required for a compiled pattern when options that changed within the
1335        pattern affected the logic of the preliminary scan that determines the
1336        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1337        that the computed length was too small. The symptoms of this bug were
1338        either the PCRE error "internal error: code overflow" from pcre_compile(),
1339        or a glibc crash with a message such as "pcretest: free(): invalid next
1340        size (fast)". Examples of patterns that provoked this bug (shown in
1341        pcretest format) are:
1343          /(?-x: )/x
1344          /(?x)(?-x: \s*#\s*)/
1345          /((?i)[\x{c0}])/8
1346          /(?i:[\x{c0}])/8
1348        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1349        is now done differently.
1351     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1352        wrapper classes; (b) implement a new function in the C++ scanner that is
1353        more efficient than the old way of doing things because it avoids levels of
1354        recursion in the regex matching; (c) add a paragraph to the documentation
1355        for the FullMatch() function.
1357     6. The escape sequence \n was being treated as whatever was defined as
1358        "newline". Not only was this contrary to the documentation, which states
1359        that \n is character 10 (hex 0A), but it also went horribly wrong when
1360        "newline" was defined as CRLF. This has been fixed.
1362     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1363        was being set to -1 for the "end of line" case (supposedly a value that no
1364        character can have). Though this value is never used (the check for end of
1365        line is "zero bytes in current character"), it caused compiler complaints.
1366        I've changed it to 0xffffffff.
1368     8. In pcre_version.c, the version string was being built by a sequence of
1369        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1370        string (as it is for production releases) called a macro with an empty
1371        argument. The C standard says the result of this is undefined. The gcc
1372        compiler treats it as an empty string (which was what was wanted) but it is
1373        reported that Visual C gives an error. The source has been hacked around to
1374        avoid this problem.
1376     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1377        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1378        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1379        of them did).
1381    10. Originally, pcretest opened its input and output without "b"; then I was
1382        told that "b" was needed in some environments, so it was added for release
1383        5.0 to both the input and output. (It makes no difference on Unix-like
1384        systems.) Later I was told that it is wrong for the input on Windows. I've
1385        now abstracted the modes into two macros, to make it easier to fiddle with
1386        them, and removed "b" from the input mode under Windows.
1388    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1390    12. Added -help and --help to pcretest as an official way of being reminded
1391        of the options.
1393    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1394        and pcrecpp.cc because they annoy compilers at high warning levels.
1396    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1398    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1399        scripts are not C programs :-) and which was not noticed because it works
1400        on Linux.
1402    16. pcretest is supposed to handle any length of pattern and data line (as one
1403        line or as a continued sequence of lines) by extending its input buffer if
1404        necessary. This feature was broken for very long pattern lines, leading to
1405        a string of junk being passed to pcre_compile() if the pattern was longer
1406        than about 50K.
1408    17. I have done a major re-factoring of the way pcre_compile() computes the
1409        amount of memory needed for a compiled pattern. Previously, there was code
1410        that made a preliminary scan of the pattern in order to do this. That was
1411        OK when PCRE was new, but as the facilities have expanded, it has become
1412        harder and harder to keep it in step with the real compile phase, and there
1413        have been a number of bugs (see for example, 4 above). I have now found a
1414        cunning way of running the real compile function in a "fake" mode that
1415        enables it to compute how much memory it would need, while actually only
1416        ever using a few hundred bytes of working memory and without too many
1417        tests of the mode. This should make future maintenance and development
1418        easier. A side effect of this work is that the limit of 200 on the nesting
1419        depth of parentheses has been removed (though this was never a serious
1420        limitation, I suspect). However, there is a downside: pcre_compile() now
1421        runs more slowly than before (30% or more, depending on the pattern). I
1422        hope this isn't a big issue. There is no effect on runtime performance.
1424    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1425        newline (only possible for the last line of a file) and it was a
1426        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1428    19. Added additional timing features to pcretest. (1) The -tm option now times
1429        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1430        separate command line item, by a number that specifies the number of
1431        repeats to use when timing. The default is 50000; this gives better
1432        precision, but takes uncomfortably long for very large patterns.
1434    20. Extended pcre_study() to be more clever in cases where a branch of a
1435        subpattern has no definite first character. For example, (a*|b*)[cd] would
1436        previously give no result from pcre_study(). Now it recognizes that the
1437        first character must be a, b, c, or d.
1439    21. There was an incorrect error "recursive call could loop indefinitely" if
1440        a subpattern (or the entire pattern) that was being tested for matching an
1441        empty string contained only one non-empty item after a nested subpattern.
1442        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1443        incorrectly, because the \d was being skipped in the check.
1445    22. The pcretest program now has a new pattern option /B and a command line
1446        option -b, which is equivalent to adding /B to every pattern. This causes
1447        it to show the compiled bytecode, without the additional information that
1448        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1449        is the same as /B/I).
1451    23. A new optimization is now able automatically to treat some sequences such
1452        as a*b as a*+b. More specifically, if something simple (such as a character
1453        or a simple class like \d) has an unlimited quantifier, and is followed by
1454        something that cannot possibly match the quantified thing, the quantifier
1455        is automatically "possessified".
1457    24. A recursive reference to a subpattern whose number was greater than 39
1458        went wrong under certain circumstances in UTF-8 mode. This bug could also
1459        have affected the operation of pcre_study().
1461    25. Realized that a little bit of performance could be had by replacing
1462        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1464    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1466    27. Possessive quantifiers such as a++ were previously implemented by turning
1467        them into atomic groups such as ($>a+). Now they have their own opcodes,
1468        which improves performance. This includes the automatically created ones
1469        from 23 above.
1471    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1472        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1473        the first matched character to be a colon. This applied both to named and
1474        numbered groups.
1476    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1478    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1479        building PCRE on Windows easier, so I have included it in the distribution.
1481    31. There is now a check in pcretest against a ridiculously large number being
1482        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1483        loop, the loop is abandoned.
1485    32. Forward references to subpatterns in conditions such as (?(2)...) where
1486        subpattern 2 is defined later cause pcre_compile() to search forwards in
1487        the pattern for the relevant set of parentheses. This search went wrong
1488        when there were unescaped parentheses in a character class, parentheses
1489        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1491    33. "Subroutine" calls and backreferences were previously restricted to
1492        referencing subpatterns earlier in the regex. This restriction has now
1493        been removed.
1495    34. Added a number of extra features that are going to be in Perl 5.10. On the
1496        whole, these are just syntactic alternatives for features that PCRE had
1497        previously implemented using the Python syntax or my own invention. The
1498        other formats are all retained for compatibility.
1500        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1501            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1502            also .NET compatible.
1504        (b) A recursion or subroutine call to a named group can now be defined as
1505            (?&name) as well as (?P>name).
1507        (c) A backreference to a named group can now be defined as \k<name> or
1508            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1509            5.10, are also .NET compatible.
1511        (d) A conditional reference to a named group can now use the syntax
1512            (?(<name>) or (?('name') as well as (?(name).
1514        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1515            groups (named and numbered) that are never evaluated inline, but can be
1516            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1517            is always false. There may be only one alternative in such a group.
1519        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1520            as the simple (?(R). The condition is true only if the most recent
1521            recursion is that of the given number or name. It does not search out
1522            through the entire recursion stack.
1524        (g) The escape \gN or \g{N} has been added, where N is a positive or
1525            negative number, specifying an absolute or relative reference.
1527    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1528        some "unreachable code" warnings.
1530    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1531        things, this adds five new scripts.
1533    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1534        There were also incompatibilities regarding the handling of \Q..\E inside
1535        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1536        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1538    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1539        matches an empty string, and forcibly breaks the loop. There were bugs in
1540        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1541        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1542        separate and independent bugs (that affected different cases) have been
1543        fixed.
1545    39. Refactored the code to abolish the use of different opcodes for small
1546        capturing bracket numbers. This is a tidy that I avoided doing when I
1547        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1548        The new approach is not only tidier, it makes it possible to reduce the
1549        memory needed to fix the previous bug (38).
1551    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1552        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1553        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1554        mode.
1556    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1557        report.
1559    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1560        copy construction and assignment in the C++ wrapper.
1562    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1563        couple of bugs that could have given wrong results in the "--newline=crlf"
1564        case.
1566    44. Added a number of casts and did some reorganization of signed/unsigned int
1567        variables following suggestions from Dair Grant. Also renamed the variable
1568        "this" as "item" because it is a C++ keyword.
1570    45. Arranged for dftables to add
1572          #include "pcre_internal.h"
1574        to pcre_chartables.c because without it, gcc 4.x may remove the array
1575        definition from the final binary if PCRE is built into a static library and
1576        dead code stripping is activated.
1578    46. For an unanchored pattern, if a match attempt fails at the start of a
1579        newline sequence, and the newline setting is CRLF or ANY, and the next two
1580        characters are CRLF, advance by two characters instead of one.
1583    Version 6.7 04-Jul-06
1584    ---------------------
1586     1. In order to handle tests when input lines are enormously long, pcretest has
1587        been re-factored so that it automatically extends its buffers when
1588        necessary. The code is crude, but this _is_ just a test program. The
1589        default size has been increased from 32K to 50K.
1591     2. The code in pcre_study() was using the value of the re argument before
1592        testing it for NULL. (Of course, in any sensible call of the function, it
1593        won't be NULL.)
1595     3. The memmove() emulation function in pcre_internal.h, which is used on
1596        systems that lack both memmove() and bcopy() - that is, hardly ever -
1597        was missing a "static" storage class specifier.
1599     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1600        containing an extended class (one that cannot be represented by a bitmap
1601        because it contains high-valued characters or Unicode property items, e.g.
1602        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1603        pattern, but PCRE should not loop if you do not (it no longer does).
1604        [Detail: two cases were found: (a) a repeated subpattern containing an
1605        extended class; (b) a recursive reference to a subpattern that followed a
1606        previous extended class. It wasn't skipping over the extended class
1607        correctly when UTF-8 mode was not set.]
1609     5. A negated single-character class was not being recognized as fixed-length
1610        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1611        compile error "lookbehind assertion is not fixed length".
1613     6. The RunPerlTest auxiliary script was showing an unexpected difference
1614        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1615        write a Perl script that can interpret lines of an input file either as
1616        byte characters or as UTF-8, which is what "perltest" was being required to
1617        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1618        can't do is switch easily at run time between having the "use utf8;" pragma
1619        or not. In the end, I fudged it by using the RunPerlTest script to insert
1620        "use utf8;" explicitly for the UTF-8 tests.
1622     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1623        the end of the subject string, contrary to the documentation and to what
1624        Perl does. This was true of both matching functions. Now it matches only at
1625        the start of the subject and immediately after *internal* newlines.
1627     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1628        a pointer to an int instead of a pointer to an unsigned long int. This
1629        caused problems on 64-bit systems.
1631     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1632        instance of the 'standard' template library not being so standard".
1634    10. There was no check on the number of named subpatterns nor the maximum
1635        length of a subpattern name. The product of these values is used to compute
1636        the size of the memory block for a compiled pattern. By supplying a very
1637        long subpattern name and a large number of named subpatterns, the size
1638        computation could be caused to overflow. This is now prevented by limiting
1639        the length of names to 32 characters, and the number of named subpatterns
1640        to 10,000.
1642    11. Subpatterns that are repeated with specific counts have to be replicated in
1643        the compiled pattern. The size of memory for this was computed from the
1644        length of the subpattern and the repeat count. The latter is limited to
1645        65535, but there was no limit on the former, meaning that integer overflow
1646        could in principle occur. The compiled length of a repeated subpattern is
1647        now limited to 30,000 bytes in order to prevent this.
1649    12. Added the optional facility to have named substrings with the same name.
1651    13. Added the ability to use a named substring as a condition, using the
1652        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1653        are numbers (not recommended). Forward references are permitted.
1655    14. Added forward references in named backreferences (if you see what I mean).
1657    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1658        pattern could run off the end of the subject. For example, the pattern
1659        "(?s)(.{1,5})"8 did this with the subject "ab".
1661    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1662        PCRE_CASELESS was set when matching characters that were quantified with ?
1663        or *.
1665    17. A character class other than a single negated character that had a minimum
1666        but no maximum quantifier - for example [ab]{6,} - was not handled
1667        correctly by pce_dfa_exec(). It would match only one character.
1669    18. A valid (though odd) pattern that looked like a POSIX character
1670        class but used an invalid character after [ (for example [[,abc,]]) caused
1671        pcre_compile() to give the error "Failed: internal error: code overflow" or
1672        in some cases to crash with a glibc free() error. This could even happen if
1673        the pattern terminated after [[ but there just happened to be a sequence of
1674        letters, a binary zero, and a closing ] in the memory that followed.
1676    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1677        over the years. Originally (before any Unicode support), just the bottom 8
1678        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1679        output from "man perlunicode" includes this:
1681          The regular expression compiler produces polymorphic opcodes.  That
1682          is, the pattern adapts to the data and automatically switches to
1683          the Unicode character scheme when presented with Unicode data--or
1684          instead uses a traditional byte scheme when presented with byte
1685          data.
1687        Sadly, a wide octal escape does not cause a switch, and in a string with
1688        no other multibyte characters, these octal escapes are treated as before.
1689        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1690        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1691        Unicode string.
1693        I have not perpetrated such confusion in PCRE. Up till now, it took just
1694        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1695        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1696        translate to the appropriate multibyte character.
1698    29. Applied some refactoring to reduce the number of warnings from Microsoft
1699        and Borland compilers. This has included removing the fudge introduced
1700        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1701        a warning about an unused variable.
1703    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1704        characters since release 4.0, because Perl (from release 5.004) does not.
1705        [Or at least, is documented not to: some releases seem to be in conflict
1706        with the documentation.] However, when a pattern was studied with
1707        pcre_study() and all its branches started with \s, PCRE still included VT
1708        as a possible starting character. Of course, this did no harm; it just
1709        caused an unnecessary match attempt.
1711    22. Removed a now-redundant internal flag bit that recorded the fact that case
1712        dependency changed within the pattern. This was once needed for "required
1713        byte" processing, but is no longer used. This recovers a now-scarce options
1714        bit. Also moved the least significant internal flag bit to the most-
1715        significant bit of the word, which was not previously used (hangover from
1716        the days when it was an int rather than a uint) to free up another bit for
1717        the future.
1719    23. Added support for CRLF line endings as well as CR and LF. As well as the
1720        default being selectable at build time, it can now be changed at runtime
1721        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1722        specify that it is scanning data with non-default line endings.
1724    24. Changed the definition of CXXLINK to make it agree with the definition of
1725        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1727    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1728        recursions. This makes a big different to stack usage for some patterns.
1730    26. If a subpattern containing a named recursion or subroutine reference such
1731        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1732        the space required for the compiled pattern went wrong and gave too small a
1733        value. Depending on the environment, this could lead to "Failed: internal
1734        error: code overflow at offset 49" or "glibc detected double free or
1735        corruption" errors.
1737    27. Applied patches from Google (a) to support the new newline modes and (b) to
1738        advance over multibyte UTF-8 characters in GlobalReplace.
1740    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1741        difference for some implementation of PCRE in some Windows version.
1743    29. Added some extra testing facilities to pcretest:
1745        \q<number>   in a data line sets the "match limit" value
1746        \Q<number>   in a data line sets the "match recursion limt" value
1747        -S <number>  sets the stack size, where <number> is in megabytes
1749        The -S option isn't available for Windows.
1752    Version 6.6 06-Feb-06
1753    ---------------------
1755     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1756        in pcreposix.h. I have copied the definition from pcre.h.
1758     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1759        because pcre.h is no longer a built file.
1761     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1762        not normally included in the compiled code.
1765    Version 6.5 01-Feb-06
1766    ---------------------
1768     1. When using the partial match feature with pcre_dfa_exec(), it was not
1769        anchoring the second and subsequent partial matches at the new starting
1770        point. This could lead to incorrect results. For example, with the pattern
1771        /1234/, partially matching against "123" and then "a4" gave a match.
1773     2. Changes to pcregrep:
1775        (a) All non-match returns from pcre_exec() were being treated as failures
1776            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1777            error message is output. Some extra information is given for the
1778            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1779            probably the only errors that are likely to be caused by users (by
1780            specifying a regex that has nested indefinite repeats, for instance).
1781            If there are more than 20 of these errors, pcregrep is abandoned.
1783        (b) A binary zero was treated as data while matching, but terminated the
1784            output line if it was written out. This has been fixed: binary zeroes
1785            are now no different to any other data bytes.
1787        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1788            used to set a locale for matching. The --locale=xxxx long option has
1789            been added (no short equivalent) to specify a locale explicitly on the
1790            pcregrep command, overriding the environment variables.
1792        (d) When -B was used with -n, some line numbers in the output were one less
1793            than they should have been.
1795        (e) Added the -o (--only-matching) option.
1797        (f) If -A or -C was used with -c (count only), some lines of context were
1798            accidentally printed for the final match.
1800        (g) Added the -H (--with-filename) option.
1802        (h) The combination of options -rh failed to suppress file names for files
1803            that were found from directory arguments.
1805        (i) Added the -D (--devices) and -d (--directories) options.
1807        (j) Added the -F (--fixed-strings) option.
1809        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1811        (l) Added the --colo(u)r option.
1813        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1814            is not present by default.
1816     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1817        items such as (?R) or (?1), when the recursion could match a number of
1818        alternatives. If it matched one of the alternatives, but subsequently,
1819        outside the recursion, there was a failure, the code tried to back up into
1820        the recursion. However, because of the way PCRE is implemented, this is not
1821        possible, and the result was an incorrect result from the match.
1823        In order to prevent this happening, the specification of recursion has
1824        been changed so that all such subpatterns are automatically treated as
1825        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1827     4. I had overlooked the fact that, in some locales, there are characters for
1828        which isalpha() is true but neither isupper() nor islower() are true. In
1829        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1830        and ordfeminine) are like this. This affected the treatment of \w and \W
1831        when they appeared in character classes, but not when they appeared outside
1832        a character class. The bit map for "word" characters is now created
1833        separately from the results of isalnum() instead of just taking it from the
1834        upper, lower, and digit maps. (Plus the underscore character, of course.)
1836     5. The above bug also affected the handling of POSIX character classes such as
1837        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1838        permanent tables. Instead, the bit maps for such a class were previously
1839        created as the appropriate unions of the upper, lower, and digit bitmaps.
1840        Now they are created by subtraction from the [[:word:]] class, which has
1841        its own bitmap.
1843     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1844        It is created by subtracting the vertical space characters (\x09, \x0a,
1845        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1846        subtraction was done in the overall bitmap for a character class, meaning
1847        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1848        be recognized. This bug has been fixed.
1850     7. Patches from the folks at Google:
1852          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1853          real life, but is still worth protecting against".
1855          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1856          regular expressions".
1858          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1859          have it.
1861          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1862          "configure" and the latter not, in order to fix a problem somebody had
1863          with compiling the Arg class on HP-UX.
1865          (e) Improve the error-handling of the C++ wrapper a little bit.
1867          (f) New tests for checking recursion limiting.
1869     8. The pcre_memmove() function, which is used only if the environment does not
1870        have a standard memmove() function (and is therefore rarely compiled),
1871        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1872        returning a result (though PCRE never actually uses the result).
1874     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1875        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1876        returned instead of calling malloc() with an overflowing number that would
1877        most likely cause subsequent chaos.
1879    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1881    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1882        with this option is matched, the nmatch and pmatch options of regexec() are
1883        ignored.
1885    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1886        provided in case anyone wants to the the POSIX interface with UTF-8
1887        strings.
1889    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1890        C++ linking (needed for some HP-UX environments).
1892    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1893        (unused parameter) and in the pcre_printint() function (omitted "default"
1894        switch label when the default is to do nothing).
1896    15. Added some code to make it possible, when PCRE is compiled as a C++
1897        library, to replace subject pointers for pcre_exec() with a smart pointer
1898        class, thus making it possible to process discontinuous strings.
1900    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1901        much the same function. They were added by different people who were trying
1902        to make PCRE easy to compile on non-Unix systems. It has been suggested
1903        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1904        for compiling on Windows systems. I have therefore replaced it with
1905        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1906        defaults to "extern" for C or "extern C" for C++, which works fine on
1907        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1908        SCOPE with something explicit in config.h. In addition:
1910        (a) pcreposix.h still had just "extern" instead of either of these macros;
1911            I have replaced it with PCRE_DATA_SCOPE.
1913        (b) Functions such as _pcre_xclass(), which are internal to the library,
1914            but external in the C sense, all had PCRE_EXPORT in their definitions.
1915            This is apparently wrong for the Windows case, so I have removed it.
1916            (It makes no difference on Unix-like systems.)
1918    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1919        of recursive calls to match(). This is different to MATCH_LIMIT because
1920        that limits the total number of calls to match(), not all of which increase
1921        the depth of recursion. Limiting the recursion depth limits the amount of
1922        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1923        when PCRE is compiled, and changed at run time. A patch from Google adds
1924        this functionality to the C++ interface.
1926    18. Changes to the handling of Unicode character properties:
1928        (a) Updated the table to Unicode 4.1.0.
1930        (b) Recognize characters that are not in the table as "Cn" (undefined).
1932        (c) I revised the way the table is implemented to a much improved format
1933            which includes recognition of ranges. It now supports the ranges that
1934            are defined in UnicodeData.txt, and it also amalgamates other
1935            characters into ranges. This has reduced the number of entries in the
1936            table from around 16,000 to around 3,000, thus reducing its size
1937            considerably. I realized I did not need to use a tree structure after
1938            all - a binary chop search is just as efficient. Having reduced the
1939            number of entries, I extended their size from 6 bytes to 8 bytes to
1940            allow for more data.
1942        (d) Added support for Unicode script names via properties such as \p{Han}.
1944    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1945        matching that character.
1947    20. When matching a repeated Unicode property with a minimum greater than zero,
1948        (for example \pL{2,}), PCRE could look past the end of the subject if it
1949        reached it while seeking the minimum number of characters. This could
1950        happen only if some of the characters were more than one byte long, because
1951        there is a check for at least the minimum number of bytes.
1953    21. Refactored the implementation of \p and \P so as to be more general, to
1954        allow for more different types of property in future. This has changed the
1955        compiled form incompatibly. Anybody with saved compiled patterns that use
1956        \p or \P will have to recompile them.
1958    22. Added "Any" and "L&" to the supported property types.
1960    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1961        but give a compile time error if the value is greater than 0xff.
1963    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1964        accidentally not being installed or uninstalled.
1966    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1967        made were to insert the current release number. This seemed silly, because
1968        it made things harder for people building PCRE on systems that don't run
1969        "configure". I have turned pcre.h into a distributed file, no longer built
1970        by "configure", with the version identification directly included. There is
1971        no longer a pcre.h.in file.
1973        However, this change necessitated a change to the pcre-config script as
1974        well. It is built from pcre-config.in, and one of the substitutions was the
1975        release number. I have updated configure.ac so that ./configure now finds
1976        the release number by grepping pcre.h.
1978    26. Added the ability to run the tests under valgrind.
1981    Version 6.4 05-Sep-05
1982    ---------------------
1984     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1985        "--" to be printed when multiple files were scanned, even when none of the
1986        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1987        consider it to be a bug, and have restored the previous behaviour.
1989     2. A couple of code tidies to get rid of compiler warnings.
1991     3. The pcretest program used to cheat by referring to symbols in the library
1992        whose names begin with _pcre_. These are internal symbols that are not
1993        really supposed to be visible externally, and in some environments it is
1994        possible to suppress them. The cheating is now confined to including
1995        certain files from the library's source, which is a bit cleaner.
1997     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1998        file's purpose clearer.
2000     5. Reorganized pcre_ucp_findchar().
2003    Version 6.3 15-Aug-05
2004    ---------------------
2006     1. The file libpcre.pc.in did not have general read permission in the tarball.
2008     2. There were some problems when building without C++ support:
2010        (a) If C++ support was not built, "make install" and "make test" still
2011            tried to test it.
2013        (b) There were problems when the value of CXX was explicitly set. Some
2014            changes have been made to try to fix these, and ...
2016        (c) --disable-cpp can now be used to explicitly disable C++ support.
2018        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2019            backslash in a target when C++ was disabled. This confuses some
2020            versions of "make", apparently. Using an intermediate variable solves
2021            this. (Same for CPP_LOBJ.)
2023     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2024        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2025        necessary on certain architectures.
2027     4. Added a setting of -export-symbols-regex to the link command to remove
2028        those symbols that are exported in the C sense, but actually are local
2029        within the library, and not documented. Their names all begin with
2030        "_pcre_". This is not a perfect job, because (a) we have to except some
2031        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2032        available (and never for static libraries). I have made a note to try to
2033        find a way round (a) in the future.
2036    Version 6.2 01-Aug-05
2037    ---------------------
2039     1. There was no test for integer overflow of quantifier values. A construction
2040        such as {1111111111111111} would give undefined results. What is worse, if
2041        a minimum quantifier for a parenthesized subpattern overflowed and became
2042        negative, the calculation of the memory size went wrong. This could have
2043        led to memory overwriting.
2045     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2047     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2048        operating environments where this matters.
2050     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2051        PCRE options from within the C++ wrapper.
2053     5. Named capturing subpatterns were not being correctly counted when a pattern
2054        was compiled. This caused two problems: (a) If there were more than 100
2055        such subpatterns, the calculation of the memory needed for the whole
2056        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2057        back references of the form \12, where the number was greater than 9, were
2058        not recognized as back references, even though there were sufficient
2059        previous subpatterns.
2061     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2062        versions of gcc, e.g. 2.95.4.
2065    Version 6.1 21-Jun-05
2066    ---------------------
2068     1. There was one reference to the variable "posix" in pcretest.c that was not
2069        surrounded by "#if !defined NOPOSIX".
2071     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2072        the cross-check on the old pcre_info() function, for the benefit of the
2073        cut-down version of PCRE that is currently imported into Exim.
2075     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2076        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2077        patterns that start (?i) but I don't think that matters. The use of (?i) is
2078        just an example; this all applies to the other options as well.
2080     4. Since libtool seems to echo the compile commands it is issuing, the output
2081        from "make" can be reduced a bit by putting "@" in front of each libtool
2082        compile command.
2084     5. Patch from the folks at Google for configure.in to be a bit more thorough
2085        in checking for a suitable C++ installation before trying to compile the
2086        C++ stuff. This should fix a reported problem when a compiler was present,
2087        but no suitable headers.
2089     6. The man pages all had just "PCRE" as their title. I have changed them to
2090        be the relevant file name. I have also arranged that these names are
2091        retained in the file doc/pcre.txt, which is a concatenation in text format
2092        of all the man pages except the little individual ones for each function.
2094     7. The NON-UNIX-USE file had not been updated for the different set of source
2095        files that come with release 6. I also added a few comments about the C++
2096        wrapper.
2099    Version 6.0 07-Jun-05
2100    ---------------------
2102     1. Some minor internal re-organization to help with my DFA experiments.
2104     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2105        didn't matter for the library itself when fully configured, but did matter
2106        when compiling without UCP support, or within Exim, where the ucp files are
2107        not imported.
2109     3. Refactoring of the library code to split up the various functions into
2110        different source modules. The addition of the new DFA matching code (see
2111        below) to a single monolithic source would have made it really too
2112        unwieldy, quite apart from causing all the code to be include in a
2113        statically linked application, when only some functions are used. This is
2114        relevant even without the DFA addition now that patterns can be compiled in
2115        one application and matched in another.
2117        The downside of splitting up is that there have to be some external
2118        functions and data tables that are used internally in different modules of
2119        the library but which are not part of the API. These have all had their
2120        names changed to start with "_pcre_" so that they are unlikely to clash
2121        with other external names.
2123     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2124        a different (DFA) algorithm. Although it is slower than the original
2125        function, it does have some advantages for certain types of matching
2126        problem.
2128     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2129        including restarting after a partial match.
2131     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2132        defined when compiling for Windows was sent to me. I have put it into the
2133        code, though I have no means of testing or verifying it.
2135     7. Added the pcre_refcount() auxiliary function.
2137     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2138        match before or at the first newline in the subject string. In pcretest,
2139        the /f option on a pattern can be used to set this.
2141     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2142        would behave wrongly. This has been present in PCRE since release 4.0.
2144    10. A number of changes to the pcregrep command:
2146        (a) Refactored how -x works; insert ^(...)$ instead of setting
2147            PCRE_ANCHORED and checking the length, in preparation for adding
2148            something similar for -w.
2150        (b) Added the -w (match as a word) option.
2152        (c) Refactored the way lines are read and buffered so as to have more
2153            than one at a time available.
2155        (d) Implemented a pcregrep test script.
2157        (e) Added the -M (multiline match) option. This allows patterns to match
2158            over several lines of the subject. The buffering ensures that at least
2159            8K, or the rest of the document (whichever is the shorter) is available
2160            for matching (and similarly the previous 8K for lookbehind assertions).
2162        (f) Changed the --help output so that it now says
2164              -w, --word-regex(p)
2166            instead of two lines, one with "regex" and the other with "regexp"
2167            because that confused at least one person since the short forms are the
2168            same. (This required a bit of code, as the output is generated
2169            automatically from a table. It wasn't just a text change.)
2171        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2172            option but starts with a hyphen. Could be a pattern or a path name
2173            starting with a hyphen, for instance.
2175        (h) "-" can be given as a file name to represent stdin.
2177        (i) When file names are being printed, "(standard input)" is used for
2178            the standard input, for compatibility with GNU grep. Previously
2179            "<stdin>" was used.
2181        (j) The option --label=xxx can be used to supply a name to be used for
2182            stdin when file names are being printed. There is no short form.
2184        (k) Re-factored the options decoding logic because we are going to add
2185            two more options that take data. Such options can now be given in four
2186            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2188        (l) Added the -A, -B, and -C options for requesting that lines of context
2189            around matches be printed.
2191        (m) Added the -L option to print the names of files that do not contain
2192            any matching lines, that is, the complement of -l.
2194        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2195            continue to scan other files.
2197        (o) The -s option was incorrectly implemented. For compatibility with other
2198            greps, it now suppresses the error message for a non-existent or non-
2199            accessible file (but not the return code). There is a new option called
2200            -q that suppresses the output of matching lines, which was what -s was
2201            previously doing.
2203        (p) Added --include and --exclude options to specify files for inclusion
2204            and exclusion when recursing.
2206    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2207        Hopefully, it now does.
2209    12. Missing cast in pcre_study().
2211    13. Added an "uninstall" target to the makefile.
2213    14. Replaced "extern" in the function prototypes in Makefile.in with
2214        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2215        world, but is set differently for Windows.
2217    15. Added a second compiling function called pcre_compile2(). The only
2218        difference is that it has an extra argument, which is a pointer to an
2219        integer error code. When there is a compile-time failure, this is set
2220        non-zero, in addition to the error test pointer being set to point to an
2221        error message. The new argument may be NULL if no error number is required
2222        (but then you may as well call pcre_compile(), which is now just a
2223        wrapper). This facility is provided because some applications need a
2224        numeric error indication, but it has also enabled me to tidy up the way
2225        compile-time errors are handled in the POSIX wrapper.
2227    16. Added VPATH=.libs to the makefile; this should help when building with one
2228        prefix path and installing with another. (Or so I'm told by someone who
2229        knows more about this stuff than I do.)
2231    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2232        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2233        match everything, including newlines. This is not POSIX-compatible, but
2234        somebody wanted the feature. From pcretest it can be activated by using
2235        both the P and the s flags.
2237    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2239    19. libpcre.pc was being incorrectly installed as executable.
2241    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2242        it now also looks for '\r' so that it will work unmodified on Windows.
2244    21. Added Google's contributed C++ wrapper to the distribution.
2246    22. Added some untidy missing memory free() calls in pcretest, to keep
2247        Electric Fence happy when testing.
2251    Version 5.0 13-Sep-04
2252    ---------------------
2254     1. Internal change: literal characters are no longer packed up into items
2255        containing multiple characters in a single byte-string. Each character
2256        is now matched using a separate opcode. However, there may be more than one
2257        byte in the character in UTF-8 mode.
2259     2. The pcre_callout_block structure has two new fields: pattern_position and
2260        next_item_length. These contain the offset in the pattern to the next match
2261        item, and its length, respectively.
2263     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2264        insertion of callouts before each pattern item. Added the /C option to
2265        pcretest to make use of this.
2267     4. On the advice of a Windows user, the lines
2269          #if defined(_WIN32) || defined(WIN32)
2270          _setmode( _fileno( stdout ), 0x8000 );
2271          #endif  /* defined(_WIN32) || defined(WIN32) */
2273        have been added to the source of pcretest. This apparently does useful
2274        magic in relation to line terminators.
2276     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2277        for the benefit of those environments where the "b" makes a difference.
2279     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2280        to know about it. I have put a hack into configure.in that adds in code
2281        to set GCC=yes if CC=icc. This seems to end up at a point in the
2282        generated configure script that is early enough to affect the setting of
2283        compiler options, which is what is needed, but I have no means of testing
2284        whether it really works. (The user who reported this had patched the
2285        generated configure script, which of course I cannot do.)
2287        LATER: After change 22 below (new libtool files), the configure script
2288        seems to know about icc (and also ecc). Therefore, I have commented out
2289        this hack in configure.in.
2291     7. Added support for pkg-config (2 patches were sent in).
2293     8. Negated POSIX character classes that used a combination of internal tables
2294        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2295        [[:^ascii]]. Typically, they would match almost any characters. The other
2296        POSIX classes were not broken in this way.
2298     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2299        to find the match, as PCRE was deluded into thinking that the match had to
2300        start at the start point or following a newline. The same bug applied to
2301        patterns with negative forward assertions or any backward assertions
2302        preceding ".*" at the start, unless the pattern required a fixed first
2303        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2305    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2306        starting at the last subject character, bytes beyond the end of the subject
2307        string were read.
2309    11. Renamed the variable "class" as "classbits" to make life easier for C++
2310        users. (Previously there was a macro definition, but it apparently wasn't
2311        enough.)
2313    12. Added the new field "tables" to the extra data so that tables can be passed
2314        in at exec time, or the internal tables can be re-selected. This allows
2315        a compiled regex to be saved and re-used at a later time by a different
2316        program that might have everything at different addresses.
2318    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2319        -R library as well as a -L library.
2321    14. The debugging options of pcretest (-d on the command line or D on a
2322        pattern) showed incorrect output for anything following an extended class
2323        that contained multibyte characters and which was followed by a quantifier.
2325    15. Added optional support for general category Unicode character properties
2326        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2327        support. It adds about 90K to the size of the library. The meanings of the
2328        inbuilt class escapes such as \d and \s have NOT been changed.
2330    16. Updated pcredemo.c to include calls to free() to release the memory for the
2331        compiled pattern.
2333    17. The generated file chartables.c was being created in the source directory
2334        instead of in the building directory. This caused the build to fail if the
2335        source directory was different from the building directory, and was
2336        read-only.
2338    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2339        file. No doubt somebody will tell me if they don't make sense... Also added
2340        Dan Mooney's comments about building on OpenVMS.
2342    19. Added support for partial matching via the PCRE_PARTIAL option for
2343        pcre_exec() and the \P data escape in pcretest.
2345    20. Extended pcretest with 3 new pattern features:
2347        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2348              write the compiled pattern to the file whose name is "rest-of-line".
2349              This is a straight binary dump of the data, with the saved pointer to
2350              the character tables forced to be NULL. The study data, if any, is
2351              written too. After writing, pcretest reads a new pattern.
2353        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2354              compiled pattern from the given file. There must not be any
2355              occurrences of "<" in the file name (pretty unlikely); if there are,
2356              pcretest will instead treat the initial "<" as a pattern delimiter.
2357              After reading in the pattern, pcretest goes on to read data lines as
2358              usual.
2360        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2361              and 16-bit fields in a compiled pattern, to simulate a pattern that
2362              was compiled on a host of opposite endianness.
2364    21. The pcre-exec() function can now cope with patterns that were compiled on
2365        hosts of opposite endianness, with this restriction:
2367          As for any compiled expression that is saved and used later, the tables
2368          pointer field cannot be preserved; the extra_data field in the arguments
2369          to pcre_exec() should be used to pass in a tables address if a value
2370          other than the default internal tables were used at compile time.
2372    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2373        now diagnosed as an error. Previously, most of the time, a negative number
2374        would have been treated as zero, but if in addition "ovector" was passed as
2375        NULL, a crash could occur.
2377    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2378        new versions from the libtool 1.5 distribution (the last one is a copy of
2379        a file called libtool.m4). This seems to have fixed the need to patch
2380        "configure" to support Darwin 1.3 (which I used to do). However, I still
2381        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2382        workstation).
2384    24. Changed the PCRE licence to be the more standard "BSD" licence.
2387    Version 4.5 01-Dec-03
2388    ---------------------
2390     1. There has been some re-arrangement of the code for the match() function so
2391        that it can be compiled in a version that does not call itself recursively.
2392        Instead, it keeps those local variables that need separate instances for
2393        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2394        needs to "recurse". Keeping track of where control must go is done by means
2395        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2396        hide most of the details from the main code, and operates only if
2397        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2398        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2399        operating.
2401        To make it easier for callers to provide specially tailored get/free
2402        functions for this usage, two new functions, pcre_stack_malloc, and
2403        pcre_stack_free, are used. They are always called in strict stacking order,
2404        and the size of block requested is always the same.
2406        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2407        PCRE has been compiled to use the stack or the heap for recursion. The
2408        -C option of pcretest uses this to show which version is compiled.
2410        A new data escape \S, is added to pcretest; it causes the amounts of store
2411        obtained and freed by both kinds of malloc/free at match time to be added
2412        to the output.
2414     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2415        what's available on my current Linux desktop machine.
2417     3. When matching a UTF-8 string, the test for a valid string at the start has
2418        been extended. If start_offset is not zero, PCRE now checks that it points
2419        to a byte that is the start of a UTF-8 character. If not, it returns
2420        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2421        this is necessary because there may be backward assertions in the pattern.
2422        When matching the same subject several times, it may save resources to use
2423        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2425     4. The code for checking the validity of UTF-8 strings has been tightened so
2426        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2427        containing "overlong sequences".
2429     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2430        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2431        should have been "&", but it just so happened that all the cases this let
2432        through by mistake were picked up later in the function.
2434     6. I had used a variable called "isblank" - this is a C99 function, causing
2435        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2437     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2438        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2439        so the version is shown; (c) stop "make test" echoing "./RunTest".
2441     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2443     9. The prototype for memmove() for systems that don't have it was using
2444        size_t, but the inclusion of the header that defines size_t was later. I've
2445        moved the #includes for the C headers earlier to avoid this.
2447    10. Added some adjustments to the code to make it easier to compiler on certain
2448        special systems:
2450          (a) Some "const" qualifiers were missing.
2451          (b) Added the macro EXPORT before all exported functions; by default this
2452              is defined to be empty.
2453          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2454              that it reads its output file name as an argument instead of writing
2455              to the standard output and assuming this can be redirected.
2457    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2458        class containing characters with values greater than 255, PCRE compilation
2459        went into a loop.
2461    12. A recursive reference to a subpattern that was within another subpattern
2462        that had a minimum quantifier of zero caused PCRE to crash. For example,
2463        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2464        recursion. If the recursively-called subpattern itself had a zero repeat,
2465        that was OK.
2467    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2468        buffer into which it was copied (for escape processing) was still set at
2469        1024, so long lines caused crashes.
2471    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2472        "internal error: code overflow...". This applied to any character class
2473        that was followed by a possessive quantifier.
2475    15. Modified the Makefile to add libpcre.la as a prerequisite for
2476        libpcreposix.la because I was told this is needed for a parallel build to
2477        work.
2479    16. If a pattern that contained .* following optional items at the start was
2480        studied, the wrong optimizing data was generated, leading to matching
2481        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2482        matching string must start with a or b or c. The correct conclusion for
2483        this pattern is that a match can start with any character.
2486    Version 4.4 13-Aug-03
2487    ---------------------
2489     1. In UTF-8 mode, a character class containing characters with values between
2490        127 and 255 was not handled correctly if the compiled pattern was studied.
2491        In fixing this, I have also improved the studying algorithm for such
2492        classes (slightly).
2494     2. Three internal functions had redundant arguments passed to them. Removal
2495        might give a very teeny performance improvement.
2497     3. Documentation bug: the value of the capture_top field in a callout is *one
2498        more than* the number of the hightest numbered captured substring.
2500     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2501        in incorrectly linking with a previously installed version. They now link
2502        explicitly with libpcre.la.
2504     5. configure.in no longer needs to recognize Cygwin specially.
2506     6. A problem in pcre.in for Windows platforms is fixed.
2508     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2509        pcretest, it used to include the size of the study block as part of its
2510        output. Unfortunately, the structure contains a field that has a different
2511        size on different hardware architectures. This meant that the tests that
2512        showed this size failed. As the block is currently always of a fixed size,
2513        this information isn't actually particularly useful in pcretest output, so
2514        I have just removed it.
2516     8. Three pre-processor statements accidentally did not start in column 1.
2517        Sadly, there are *still* compilers around that complain, even though
2518        standard C has not required this for well over a decade. Sigh.
2520     9. In pcretest, the code for checking callouts passed small integers in the
2521        callout_data field, which is a void * field. However, some picky compilers
2522        complained about the casts involved for this on 64-bit systems. Now
2523        pcretest passes the address of the small integer instead, which should get
2524        rid of the warnings.
2526    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2527        both compile and run time, and gives an error if an invalid UTF-8 sequence
2528        is found. There is a option for disabling this check in cases where the
2529        string is known to be correct and/or the maximum performance is wanted.
2531    11. In response to a bug report, I changed one line in Makefile.in from
2533            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2534        to
2535            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2537        to look similar to other lines, but I have no way of telling whether this
2538        is the right thing to do, as I do not use Windows. No doubt I'll get told
2539        if it's wrong...
2542    Version 4.3 21-May-03
2543    ---------------------
2545    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2546       Makefile.
2548    2. Some refactoring to improve the quality of the code:
2550       (i)   The utf8_table... variables are now declared "const".
2552       (ii)  The code for \cx, which used the "case flipping" table to upper case
2553             lower case letters, now just substracts 32. This is ASCII-specific,
2554             but the whole concept of \cx is ASCII-specific, so it seems
2555             reasonable.
2557       (iii) PCRE was using its character types table to recognize decimal and
2558             hexadecimal digits in the pattern. This is silly, because it handles
2559             only 0-9, a-f, and A-F, but the character types table is locale-
2560             specific, which means strange things might happen. A private
2561             table is now used for this - though it costs 256 bytes, a table is
2562             much faster than multiple explicit tests. Of course, the standard
2563             character types table is still used for matching digits in subject
2564             strings against \d.
2566       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2567             ending in _t are). So I've renamed it as ESC_tee.
2569    3. The first argument for regexec() in the POSIX wrapper should have been
2570       defined as "const".
2572    4. Changed pcretest to use malloc() for its buffers so that they can be
2573       Electric Fenced for debugging.
2575    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2576       to read one or more bytes before the start of the subject string. Often this
2577       had no effect on PCRE's behaviour, but in some circumstances it could
2578       provoke a segmentation fault.
2580    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2581       to try to read one or more bytes before the start of the subject string.
2583    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2584       UTF-8 support could misbehave in various ways if the subject string
2585       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2586       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2587       back over UTF-8 characters.)
2590    Version 4.2 14-Apr-03
2591    ---------------------
2593    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2595    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2596         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2597         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2598         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2599         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2600           and BUILD_EXEEXT
2601         Note: automatic setting of the BUILD variables is not yet working
2602         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2603           compile-time but not at link-time
2604         [LINK]: use for linking executables only
2605         make different versions for Windows and non-Windows
2606         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2607           libraries
2608         [LINK_FOR_BUILD]: new variable
2609         [OBJEXT]: use throughout
2610         [EXEEXT]: use throughout
2611         <winshared>: new target
2612         <wininstall>: new target
2613         <dftables.o>: use native compiler
2614         <dftables>: use native linker
2615         <install>: handle Windows platform correctly
2616         <clean>: ditto
2617         <check>: ditto
2618         copy DLL to top builddir before testing
2620       As part of these changes, -no-undefined was removed again. This was reported
2621       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2622       in any case.
2624    3. Some tidies to get rid of compiler warnings:
2626       . In the match_data structure, match_limit was an unsigned long int, whereas
2627         match_call_count was an int. I've made them both unsigned long ints.
2629       . In pcretest the fact that a const uschar * doesn't automatically cast to
2630         a void * provoked a warning.
2632       . Turning on some more compiler warnings threw up some "shadow" variables
2633         and a few more missing casts.
2635    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2636       option, a class that contained a single character with a value between 128
2637       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2639    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2640       option, a class that contained several characters, but with at least one
2641       whose value was between 128 and 255 caused PCRE to crash.
2644    Version 4.1 12-Mar-03
2645    ---------------------
2647    1. Compiling with gcc -pedantic found a couple of places where casts were
2648    needed, and a string in dftables.c that was longer than standard compilers are
2649    required to support.
2651    2. Compiling with Sun's compiler found a few more places where the code could
2652    be tidied up in order to avoid warnings.
2654    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2655    first of these names is deprecated in the latest Autoconf in favour of the name
2656    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2657    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2658    analogy I have changed it to CFLAGS_FOR_BUILD.
2660    4. Added -no-undefined to the linking command in the Makefile, because this is
2661    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2662    linking step for the pcreposix library.
2664    5. PCRE was failing to diagnose the case of two named groups with the same
2665    name.
2667    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2668    literal character that is needed in the subject for a match, and scans along to
2669    ensure that it is present before embarking on the full matching process. This
2670    saves time in cases of nested unlimited repeats that are never going to match.
2671    Problem: the scan can take a lot of time if the subject is very long (e.g.
2672    megabytes), thus penalizing straightforward matches. It is now done only if the
2673    amount of subject to be scanned is less than 1000 bytes.
2675    7. A lesser problem with the same optimization is that it was recording the
2676    first character of an anchored pattern as "needed", thus provoking a search
2677    right along the subject, even when the first match of the pattern was going to
2678    fail. The "needed" character is now not set for anchored patterns, unless it
2679    follows something in the pattern that is of non-fixed length. Thus, it still
2680    fulfils its original purpose of finding quick non-matches in cases of nested
2681    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2684    Version 4.0 17-Feb-03
2685    ---------------------
2687    1. If a comment in an extended regex that started immediately after a meta-item
2688    extended to the end of string, PCRE compiled incorrect data. This could lead to
2689    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2691    2. Moved to autoconf 2.53 and libtool 1.4.2.
2693    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2694    the special perltest8 script is no longer needed - all the tests can be run
2695    from a single perltest script.
2697    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2698    by \s. It has now been removed in PCRE. This means it isn't recognized as
2699    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2700    class [:space:] *does* include VT, thereby creating a mess.
2702    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2703    space and tab.
2705    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2706    its new features into the main test script, reducing the number of scripts.
2708    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2709    were backward compatible, and made the (?i) apply to the whole pattern, as if
2710    /i were given. Now it behaves more logically, and applies the option setting
2711    only to what follows. PCRE has been changed to follow suit. However, if it
2712    finds options settings right at the start of the pattern, it extracts them into
2713    the global options, as before. Thus, they show up in the info data.
2715    8. Added support for the \Q...\E escape sequence. Characters in between are
2716    treated as literals. This is slightly different from Perl in that $ and @ are
2717    also handled as literals inside the quotes. In Perl, they will cause variable
2718    interpolation. Note the following examples:
2720        Pattern            PCRE matches      Perl matches
2722        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2723        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2724        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2726    For compatibility with Perl, \Q...\E sequences are recognized inside character
2727    classes as well as outside them.
2729    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2730    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2731    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2732    signed/unsigned warnings.
2734    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2735    option for pcretest, so I've replaced it by a simple function that does just
2736    that job.
2738    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2739    "pcregrep -".
2741    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2742    Java package. This provides some syntactic sugar for simple cases of what my
2743    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2744    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2745    item, you can use this simplified notation. Note that only makes sense with
2746    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2747    greediness, whatever the setting of the PCRE_UNGREEDY option.
2749    13. A change of greediness default within a pattern was not taking effect at
2750    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2751    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2752    was abstracted outside.
2754    14. PCRE now supports the \G assertion. It is true when the current matching
2755    position is at the start point of the match. This differs from \A when the
2756    starting offset is non-zero. Used with the /g option of pcretest (or similar
2757    code), it works in the same way as it does for Perl's /g option. If all
2758    alternatives of a regex begin with \G, the expression is anchored to the start
2759    match position, and the "anchored" flag is set in the compiled expression.
2761    15. Some bugs concerning the handling of certain option changes within patterns
2762    have been fixed. These applied to options other than (?ims). For example,
2763    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2764    been the other way round. Some of this was related to change 7 above.
2766    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2767    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2768    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2769    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2771    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2772    mode. Unlike ".", it always matches newline, whatever the setting of
2773    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2774    assertions. Perl allows it, but it doesn't (in general) work because it can't
2775    calculate the length of the lookbehind. At least, that's the case for Perl
2776    5.8.0 - I've been told they are going to document that it doesn't work in
2777    future.
2779    18. Added an error diagnosis for escapes that PCRE does not support: these are
2780    \L, \l, \N, \P, \p, \U, \u, and \X.
2782    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2783    reading past the end of the pattern in cases such as /[abcd/.
2785    20. PCRE was getting more memory than necessary for patterns with classes that
2786    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2788    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2789    compiling PCRE for use with Virtual Pascal.
2791    22. Small fix to the Makefile to make it work properly if the build is done
2792    outside the source tree.
2794    23. Added a new extension: a condition to go with recursion. If a conditional
2795    subpattern starts with (?(R) the "true" branch is used if recursion has
2796    happened, whereas the "false" branch is used only at the top level.
2798    24. When there was a very long string of literal characters (over 255 bytes
2799    without UTF support, over 250 bytes with UTF support), the computation of how
2800    much memory was required could be incorrect, leading to segfaults or other
2801    strange effects.
2803    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2804    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2805    there was a subsequent back reference to those brackets. This meant that, for
2806    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2807    possible to check for precisely this case. All we can do is abandon the
2808    optimization if .* occurs inside capturing brackets when there are any back
2809    references whatsoever. (See below for a better fix that came later.)
2811    26. The handling of the optimization for finding the first character of a
2812    non-anchored pattern, and for finding a character that is required later in the
2813    match were failing in some cases. This didn't break the matching; it just
2814    failed to optimize when it could. The way this is done has been re-implemented.
2816    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2818    28. Added a new feature that provides some of the functionality that Perl
2819    provides with (?{...}). The facility is termed a "callout". The way it is done
2820    in PCRE is for the caller to provide an optional function, by setting
2821    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2822    global variable. By default it is unset, which disables all calling out. To get
2823    the function called, the regex must include (?C) at appropriate points. This
2824    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2825    This provides a means of identifying different callout points. When PCRE
2826    reaches such a point in the regex, if pcre_callout has been set, the external
2827    function is called. It is provided with data in a structure called
2828    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2829    matching continues; if it returns a non-zero value, the match at the current
2830    point fails. However, backtracking will occur if possible. [This was changed
2831    later and other features added - see item 49 below.]
2833    29. pcretest is upgraded to test the callout functionality. It provides a
2834    callout function that displays information. By default, it shows the start of
2835    the match and the current position in the text. There are some new data escapes
2836    to vary what happens:
2838        \C+         in addition, show current contents of captured substrings
2839        \C-         do not supply a callout function
2840        \C!n        return 1 when callout number n is reached
2841        \C!n!m      return 1 when callout number n is reached for the mth time
2843    30. If pcregrep was called with the -l option and just a single file name, it
2844    output "<stdin>" if a match was found, instead of the file name.
2846    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2847    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2848    pcre_exec(). This saves a malloc/free per call. The default value of
2849    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2850    when configuring.
2852    32. The default maximum size of a compiled pattern is 64K. There have been a
2853    few cases of people hitting this limit. The code now uses macros to handle the
2854    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2855    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2856    configuring. Tests 2 and 5 work only with 2-byte links because they output
2857    debugging information about compiled patterns.
2859    33. Internal code re-arrangements:
2861    (a) Moved the debugging function for printing out a compiled regex into
2862        its own source file (printint.c) and used #include to pull it into
2863        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2864        separate copies.
2866    (b) Defined the list of op-code names for debugging as a macro in
2867        internal.h so that it is next to the definition of the opcodes.
2869    (c) Defined a table of op-code lengths for simpler skipping along compiled
2870        code. This is again a macro in internal.h so that it is next to the
2871        definition of the opcodes.
2873    34. Added support for recursive calls to individual subpatterns, along the
2874    lines of Robin Houston's patch (but implemented somewhat differently).
2876    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2877    allow it to read and process whole directories in Win32. This code was
2878    contributed by Lionel Fourquaux; it has not been tested by me.
2880    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2881    used to name a group. Names consist of alphanumerics and underscores, and must
2882    be unique. Back references use the syntax (?P=name) and recursive calls use
2883    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2884    numbers. The function pcre_fullinfo() can be used after compilation to extract
2885    a name/number map. There are three relevant calls:
2887      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2888      PCRE_INFO_NAMECOUNT            yields the number of entries
2889      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2891    The map is a vector of fixed-size entries. The size of each entry depends on
2892    the length of the longest name used. The first two bytes of each entry are the
2893    group number, most significant byte first. There follows the corresponding
2894    name, zero terminated. The names are in alphabetical order.
2896    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2897    case instead of 255. Making it the same both with and without UTF-8 support
2898    means that the same test output works with both.
2900    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2901    calling malloc() with a zero argument.
2903    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2904    optimization. I've improved things by keeping a bitmap of backreferences with
2905    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2906    fact referenced, the optimization can be applied. It is unlikely that a
2907    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2908    the match to follow \n) will appear inside brackets with a number greater than
2909    31, but if it does, any back reference > 31 suppresses the optimization.
2911    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2912    of disabling numbered capturing parentheses. Any opening parenthesis that is
2913    not followed by ? behaves as if it were followed by ?: but named parentheses
2914    can still be used for capturing (and they will acquire numbers in the usual
2915    way).
2917    41. Redesigned the return codes from the match() function into yes/no/error so
2918    that errors can be passed back from deep inside the nested calls. A malloc
2919    failure while inside a recursive subpattern call now causes the
2920    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2922    42. It is now possible to set a limit on the number of times the match()
2923    function is called in a call to pcre_exec(). This facility makes it possible to
2924    limit the amount of recursion and backtracking, though not in a directly
2925    obvious way, because the match() function is used in a number of different
2926    circumstances. The count starts from zero for each position in the subject
2927    string (for non-anchored patterns). The default limit is, for compatibility, a
2928    large number, namely 10 000 000. You can change this in two ways:
2930    (a) When configuring PCRE before making, you can use --with-match-limit=n
2931        to set a default value for the compiled library.
2933    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2934        a different value is set. See 45 below.
2936    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2938    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2939    of things that can be changed at compile time. The first argument specifies
2940    what is wanted and the second points to where the information is to be placed.
2941    The current list of available information is:
2943      PCRE_CONFIG_UTF8
2945    The output is an integer that is set to one if UTF-8 support is available;
2946    otherwise it is set to zero.
2950    The output is an integer that it set to the value of the code that is used for
2951    newline. It is either LF (10) or CR (13).
2955    The output is an integer that contains the number of bytes used for internal
2956    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2960    The output is an integer that contains the threshold above which the POSIX
2961    interface uses malloc() for output vectors. See item 31 above.
2965    The output is an unsigned integer that contains the default limit of the number
2966    of match() calls in a pcre_exec() execution. See 42 above.
2968    44. pcretest has been upgraded by the addition of the -C option. This causes it
2969    to extract all the available output from the new pcre_config() function, and to
2970    output it. The program then exits immediately.
2972    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2973    order to support additional features. One way would have been to define
2974    pcre_exec2() (for example) with extra arguments, but this would not have been
2975    extensible, and would also have required all calls to the original function to
2976    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2977    is used for passing in "extra" data from pcre_study().
2979    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2980    contains the following fields:
2982      flags         a bitmap indicating which of the following fields are set
2983      study_data    opaque data from pcre_study()
2984      match_limit   a way of specifying a limit on match() calls for a specific
2985                      call to pcre_exec()
2986      callout_data  data for callouts (see 49 below)
2988    The flag bits are also defined in pcre.h, and are
2994    The pcre_study() function now returns one of these new pcre_extra blocks, with
2995    the actual study data pointed to by the study_data field, and the
2996    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2997    before. That is, this change is entirely upwards-compatible and requires no
2998    change to existing code.
3000    If you want to pass in additional data to pcre_exec(), you can either place it
3001    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3002    block.
3004    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3005    data string contains the escape sequence \M, pcretest calls pcre_exec() several
3006    times with different match limits, until it finds the minimum value needed for
3007    pcre_exec() to complete. The value is then output. This can be instructive; for
3008    most simple matches the number is quite small, but for pathological cases it
3009    gets very large very quickly.
3011    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3012    returns the size of the data block pointed to by the study_data field in a
3013    pcre_extra block, that is, the value that was passed as the argument to
3014    pcre_malloc() when PCRE was getting memory in which to place the information
3015    created by pcre_study(). The fourth argument should point to a size_t variable.
3016    pcretest has been extended so that this information is shown after a successful
3017    pcre_study() call when information about the compiled regex is being displayed.
3019    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3020    because what follows is always an absolute path. (Later: it turns out that this
3021    is more than cosmetic for MinGW, because it doesn't like empty path
3022    components.)
3024    49. Some changes have been made to the callout feature (see 28 above):
3026    (i)  A callout function now has three choices for what it returns:
3028           0  =>  success, carry on matching
3029         > 0  =>  failure at this point, but backtrack if possible
3030         < 0  =>  serious error, return this value from pcre_exec()
3032         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3033         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3034         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3035         use by callout functions. It will never be used by PCRE itself.
3037    (ii) The pcre_extra structure (see 45 above) has a void * field called
3038         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3039         pcre_callout_block structure has a field of the same name. The contents of
3040         the field passed in the pcre_extra structure are passed to the callout
3041         function in the corresponding field in the callout block. This makes it
3042         easier to use the same callout-containing regex from multiple threads. For
3043         testing, the pcretest program has a new data escape
3045           \C*n        pass the number n (may be negative) as callout_data
3047         If the callout function in pcretest receives a non-zero value as
3048         callout_data, it returns that value.
3050    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3051    there were some redundant $(CFLAGS) in commands that are now specified as
3052    $(LINK), which already includes $(CFLAGS).
3054    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3055    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3056    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3057    one-byte characters throughout. Note that case-insensitive matching applies
3058    only to characters whose values are less than 256. PCRE doesn't support the
3059    notion of cases for higher-valued characters.
3061    (i)   A character class whose characters are all within 0-255 is handled as
3062          a bit map, and the map is inverted for negative classes. Previously, a
3063          character > 255 always failed to match such a class; however it should
3064          match if the class was a negative one (e.g. [^ab]). This has been fixed.
3066    (ii)  A negated character class with a single character < 255 is coded as
3067          "not this character" (OP_NOT). This wasn't working properly when the test
3068          character was multibyte, either singly or repeated.
3070    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3071          mode, for example: \x{100}{2,3}.
3073    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3074          singly or repeated) now correctly test multibyte characters. However,
3075          PCRE doesn't recognize any characters with values greater than 255 as
3076          digits, spaces, or word characters. Such characters always match \D, \S,
3077          and \W, and never match \d, \s, or \w.
3079    (v)   Classes may now contain characters and character ranges with values
3080          greater than 255. For example: [ab\x{100}-\x{400}].
3082    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3083          PCRE in UTF-8 mode.
3085    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3086    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3087    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3088    value.)
3090    53. The single man page has become too large. I have therefore split it up into
3091    a number of separate man pages. These also give rise to individual HTML pages;
3092    these are now put in a separate directory, and there is an index.html page that
3093    lists them all. Some hyperlinking between the pages has been installed.
3095    54. Added convenience functions for handling named capturing parentheses.
3097    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3098    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3099    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3100    are faulted.
3102    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3103    calling configure. These values are used when compiling the dftables.c program
3104    which is run to generate the source of the default character tables. They
3105    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3106    you will need to set these values.
3108    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3111    Version 3.9 02-Jan-02
3112    ---------------------
3114    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3116    2. If --disable-static was given, the building process failed when trying to
3117    build pcretest and pcregrep. (For some reason it was using libtool to compile
3118    them, which is not right, as they aren't part of the library.)
3121    Version 3.8 18-Dec-01
3122    ---------------------
3124    1. The experimental UTF-8 code was completely screwed up. It was packing the
3125    bytes in the wrong order. How dumb can you get?
3128    Version 3.7 29-Oct-01
3129    ---------------------
3131    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3132    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3133    this didn't happen under Solaris 8, where I normally test things.
3135    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3136    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3137    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3138    this fix an hour or so after the initial 3.7 release.)
3141    Version 3.6 23-Oct-01
3142    ---------------------
3144    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3145    offsets passed as NULL with zero offset count.
3147    2. The config.guess and config.sub files had not been updated when I moved to
3148    the latest autoconf.
3151    Version 3.5 15-Aug-01
3152    ---------------------
3154    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3155    had been forgotten.
3157    2. By using declared but undefined structures, we can avoid using "void"
3158    definitions in pcre.h while keeping the internal definitions of the structures
3159    private.
3161    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3162    user point of view, this means that both static and shared libraries are built
3163    by default, but this can be individually controlled. More of the work of
3164    handling this static/shared cases is now inside libtool instead of PCRE's make
3165    file.
3167    4. The pcretest utility is now installed along with pcregrep because it is
3168    useful for users (to test regexs) and by doing this, it automatically gets
3169    relinked by libtool. The documentation has been turned into a man page, so
3170    there are now .1, .txt, and .html versions in /doc.
3172    5. Upgrades to pcregrep:
3173       (i)   Added long-form option names like gnu grep.
3174       (ii)  Added --help to list all options with an explanatory phrase.
3175       (iii) Added -r, --recursive to recurse into sub-directories.
3176       (iv)  Added -f, --file to read patterns from a file.
3178    6. pcre_exec() was referring to its "code" argument before testing that
3179    argument for NULL (and giving an error if it was NULL).
3181    7. Upgraded Makefile.in to allow for compiling in a different directory from
3182    the source directory.
3184    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3185    options bits, the pointer it was passed was to an int instead of to an unsigned
3186    long int. This mattered only on 64-bit systems.
3188    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3189    generated) instead of pcre.in, which it its source. Also made the same change
3190    in several of the .c files.
3192    10. A new release of gcc defines printf() as a macro, which broke pcretest
3193    because it had an ifdef in the middle of a string argument for printf(). Fixed
3194    by using separate calls to printf().
3196    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3197    script, to force use of CR or LF instead of \n in the source. On non-Unix
3198    systems, the value can be set in config.h.
3200    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3201    absolute limit. Changed the text of the error message to make this clear, and
3202    likewise updated the man page.
3204    13. The limit of 99 on the number of capturing subpatterns has been removed.
3205    The new limit is 65535, which I hope will not be a "real" limit.
3208    Version 3.4 22-Aug-00
3209    ---------------------
3211    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3213    2. Diagnose condition (?(0) as an error instead of crashing on matching.
3216    Version 3.3 01-Aug-00
3217    ---------------------
3219    1. If an octal character was given, but the value was greater than \377, it
3220    was not getting masked to the least significant bits, as documented. This could
3221    lead to crashes in some systems.
3223    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3224    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3226    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3227    These just pass their arguments on to (pcre_free)(), but they are provided
3228    because some uses of PCRE bind it to non-C systems that can call its functions,
3229    but cannot call free() or pcre_free() directly.
3231    4. Add "make test" as a synonym for "make check". Corrected some comments in
3232    the Makefile.
3234    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3235    Makefile.
3237    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3238    command called pgrep for grepping around the active processes.
3240    7. Added the beginnings of support for UTF-8 character strings.
3242    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3243    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3244    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3245    out for the ar command.)
3248    Version 3.2 12-May-00
3249    ---------------------
3251    This is purely a bug fixing release.
3253    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3254    of ZA. This was just one example of several cases that could provoke this bug,
3255    which was introduced by change 9 of version 2.00. The code for breaking
3256    infinite loops after an iteration that matches an empty string was't working
3257    correctly.
3259    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3260    when matched against abbab (for example). After matching an empty string, it
3261    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3262    caused it to match further down the string than it should.
3264    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3265    was there because it doesn't seem to be needed, and it causes trouble on some
3266    systems, as it is not a Standard C header. It has been removed.
3268    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3269    were reported on the Macintosh. The changes were from
3271      while ((c = *(++ptr)) != 0 && c != '\n');
3272    to
3273      while ((c = *(++ptr)) != 0 && c != '\n') ;
3275    Totally extraordinary, but if that's what it takes...
3277    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3278    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3279    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3280    assumes the way PCRE uses memmove() (always moving upwards).
3282    6. PCRE is being used in one environment where strchr() is not available. There
3283    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3284    faster code anyway.
3287    Version 3.1 09-Feb-00
3288    ---------------------
3290    The only change in this release is the fixing of some bugs in Makefile.in for
3291    the "install" target:
3293    (1) It was failing to install pcreposix.h.
3295    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3298    Version 3.0 01-Feb-00
3299    ---------------------
3301    1. Add support for the /+ modifier to perltest (to output $` like it does in
3302    pcretest).
3304    2. Add support for the /g modifier to perltest.
3306    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3307    matches null strings.
3309    4. Fix perltest so that it doesn't do unwanted things when fed an empty
3310    pattern. Perl treats empty patterns specially - it reuses the most recent
3311    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3312    effect.
3314    5. The POSIX interface was broken in that it was just handing over the POSIX
3315    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3316    required a bigger vector, with some working space on the end. This means that
3317    the POSIX wrapper now has to get and free some memory, and copy the results.
3319    6. Added some simple autoconf support, placing the test data and the
3320    documentation in separate directories, re-organizing some of the
3321    information files, and making it build pcre-config (a GNU standard). Also added
3322    libtool support for building PCRE as a shared library, which is now the
3323    default.
3325    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3326    09 are not valid octal constants. Single digits will be used for minor values
3327    less than 10.
3329    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3330    existing programs that set these in the POSIX interface can use PCRE without
3331    modification.
3333    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3334    return all that pcre_info() returns, plus additional data. The pcre_info()
3335    function is retained for compatibility, but is considered to be obsolete.
3337    10. Added experimental recursion feature (?R) to handle one common case that
3338    Perl 5.6 will be able to do with (?p{...}).
3340    11. Added support for POSIX character classes like [:alpha:], which Perl is
3341    adopting.
3344    Version 2.08 31-Aug-99
3345    ----------------------
3347    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3348    trying to match at the startoffset position, but instead was moving forward to
3349    the next newline as if a previous match had failed.
3351    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3352    and could get into a loop if a null string was matched other than at the start
3353    of the subject.
3355    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3356    be distinguished at compile time, and for completeness also added PCRE_DATE.
3358    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3359    in GnuWin32 environments.
3362    Version 2.07 29-Jul-99
3363    ----------------------
3365    1. The documentation is now supplied in plain text form and HTML as well as in
3366    the form of man page sources.
3368    2. C++ compilers don't like assigning (void *) values to other pointer types.
3369    In particular this affects malloc(). Although there is no problem in Standard
3370    C, I've put in casts to keep C++ compilers happy.
3372    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3373    should be (const char *).
3375    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3376    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3377    However, I haven't made this a standard facility. The documentation doesn't
3378    mention it, and the Makefile doesn't support it.
3380    5. The Makefile now contains an "install" target, with editable destinations at
3381    the top of the file. The pcretest program is not installed.
3383    6. pgrep -V now gives the PCRE version number and date.
3385    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3386    causing the entire string to be ignored, instead of just the last character.
3388    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3389    non-matching string, it can take a very, very long time, even for strings of
3390    quite modest length, because of the nested recursion. PCRE now does better in
3391    some of these cases. It does this by remembering the last required literal
3392    character in the pattern, and pre-searching the subject to ensure it is present
3393    before running the real match. In other words, it applies a heuristic to detect
3394    some types of certain failure quickly, and in the above example, if presented
3395    with a string that has no trailing " it gives "no match" very quickly.
3397    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3398    other alternatives are tried instead.
3401    Version 2.06 09-Jun-99
3402    ----------------------
3404    1. Change pcretest's output for amount of store used to show just the code
3405    space, because the remainder (the data block) varies in size between 32-bit and
3406    64-bit systems.
3408    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3409    start matching at. This allows lookbehinds to work when searching for multiple
3410    occurrences in a string.
3412    3. Added additional options to pcretest for testing multiple occurrences:
3414       /+   outputs the rest of the string that follows a match
3415       /g   loops for multiple occurrences, using the new startoffset argument
3416       /G   loops for multiple occurrences by passing an incremented pointer
3418    4. PCRE wasn't doing the "first character" optimization for patterns starting
3419    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3420    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3421    the letter 'x'. On long subject strings, this gives a significant speed-up.
3424    Version 2.05 21-Apr-99
3425    ----------------------
3427    1. Changed the type of magic_number from int to long int so that it works
3428    properly on 16-bit systems.
3430    2. Fixed a bug which caused patterns starting with .* not to work correctly
3431    when the subject string contained newline characters. PCRE was assuming
3432    anchoring for such patterns in all cases, which is not correct because .* will
3433    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3434    DOTALL is set at top level; otherwise it knows that patterns starting with .*
3435    must be retried after every newline in the subject.
3438    Version 2.04 18-Feb-99
3439    ----------------------
3441    1. For parenthesized subpatterns with repeats whose minimum was zero, the
3442    computation of the store needed to hold the pattern was incorrect (too large).
3443    If such patterns were nested a few deep, this could multiply and become a real
3444    problem.
3446    2. Added /M option to pcretest to show the memory requirement of a specific
3447    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3449    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3450    compiled in such a way that the backtracking after subsequent failure was
3451    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3452    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3455    Version 2.03 02-Feb-99
3456    ----------------------
3458    1. Fixed typo and small mistake in man page.
3460    2. Added 4th condition (GPL supersedes if conflict) and created separate
3461    LICENCE file containing the conditions.
3463    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3464    Perl, that is the internal \ allows the delimiter to be included in the
3465    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3466    the final delimiter, add \ to the end of the pattern (to test the error).
3468    4. Added the convenience functions for extracting substrings after a successful
3469    match. Updated pcretest to make it able to test these functions.
3472    Version 2.02 14-Jan-99
3473    ----------------------
3475    1. Initialized the working variables associated with each extraction so that
3476    their saving and restoring doesn't refer to uninitialized store.
3478    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3479    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3480    fix the problem.
3482    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3483    calls, and wasn't printing the correct value for compiling calls. Increased the
3484    default value of LOOPREPEAT, and the number of significant figures in the
3485    times.
3487    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3489    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3490    a building problem on Windows NT with a FAT file system.
3493    Version 2.01 21-Oct-98
3494    ----------------------
3496    1. Changed the API for pcre_compile() to allow for the provision of a pointer
3497    to character tables built by pcre_maketables() in the current locale. If NULL
3498    is passed, the default tables are used.
3501    Version 2.00 24-Sep-98
3502    ----------------------
3504    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3505    it any more.
3507    2. Allow quantification of (?>) groups, and make it work correctly.
3509    3. The first character computation wasn't working for (?>) groups.
3511    4. Correct the implementation of \Z (it is permitted to match on the \n at the
3512    end of the subject) and add 5.005's \z, which really does match only at the
3513    very end of the subject.
3515    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3517    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3518    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3519    localized options. All options to pcre_study() were also removed.
3521    7. Add other new features from 5.005:
3523       $(?<=           positive lookbehind
3524       $(?<!           negative lookbehind
3525       (?imsx-imsx)    added the unsetting capability
3526                       such a setting is global if at outer level; local otherwise
3527       (?imsx-imsx:)   non-capturing groups with option setting
3528       (?(cond)re|re)  conditional pattern matching
3530       A backreference to itself in a repeated group matches the previous
3531       captured string.
3533    8. General tidying up of studying (both automatic and via "study")
3534    consequential on the addition of new assertions.
3536    9. As in 5.005, unlimited repeated groups that could match an empty substring
3537    are no longer faulted at compile time. Instead, the loop is forcibly broken at
3538    runtime if any iteration does actually match an empty substring.
3540    10. Include the RunTest script in the distribution.
3542    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3543    discrepancies, some of which were old and were also with respect to 5.004. They
3544    have now been fixed.
3547    Version 1.09 28-Apr-98
3548    ----------------------
3550    1. A negated single character class followed by a quantifier with a minimum
3551    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
3552    program crashes, or just wrong answers. This did not apply to negated classes
3553    containing more than one character, or to minima other than one.
3556    Version 1.08 27-Mar-98
3557    ----------------------
3559    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3561    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3562    latter must appear before anything that relies on it in the pattern.
3565    Version 1.07 16-Feb-98
3566    ----------------------
3568    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3569    repeat of a potentially empty string).
3572    Version 1.06 23-Jan-98
3573    ----------------------
3575    1. Added Markus Oberhumer's little patches for C++.
3577    2. Literal strings longer than 255 characters were broken.
3580    Version 1.05 23-Dec-97
3581    ----------------------
3583    1. Negated character classes containing more than one character were failing if
3584    PCRE_CASELESS was set at run time.
3587    Version 1.04 19-Dec-97
3588    ----------------------
3590    1. Corrected the man page, where some "const" qualifiers had been omitted.
3592    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3593    input syntax.
3595    3. Fixed memory leak which occurred when a regex with back references was
3596    matched with an offsets vector that wasn't big enough. The temporary memory
3597    that is used in this case wasn't being freed if the match failed.
3599    4. Tidied pcretest to ensure it frees memory that it gets.
3601    5. Temporary memory was being obtained in the case where the passed offsets
3602    vector was exactly big enough.
3604    6. Corrected definition of offsetof() from change 5 below.
3606    7. I had screwed up change 6 below and broken the rules for the use of
3607    setjmp(). Now fixed.
3610    Version 1.03 18-Dec-97
3611    ----------------------
3613    1. A erroneous regex with a missing opening parenthesis was correctly
3614    diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3615    on some systems.
3617    2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3618    it was reported that one broken compiler failed on the former because "code" is
3619    also an independent variable.
3621    3. The erroneous regex a[]b caused an array overrun reference.
3623    4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3624    fail on data ending with that character. (It was going on too far, and checking
3625    the next character, typically a binary zero.) This was specific to the
3626    optimized code for single-character negative classes.
3628    5. Added a contributed patch from the TIN world which does the following:
3630      + Add an undef for memmove, in case the the system defines a macro for it.
3632      + Add a definition of offsetof(), in case there isn't one. (I don't know
3633        the reason behind this - offsetof() is part of the ANSI standard - but
3634        it does no harm).
3636      + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3637        most of the places where whitespace preceded '#'. I have given up and
3638        allowed the remaining 2 cases to be at the margin.
3640      + Rename some variables in pcre to eliminate shadowing. This seems very
3641        pedantic, but does no harm, of course.
3643    6. Moved the call to setjmp() into its own function, to get rid of warnings
3644    from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3646    7. Constructs such as \d{8,} were compiling into the equivalent of
3647    \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3648    outcome, but in this particular case used more store than had been allocated,
3649    which caused the bug to be discovered because it threw up an internal error.
3651    8. The debugging code in both pcre and pcretest for outputting the compiled
3652    form of a regex was going wrong in the case of back references followed by
3653    curly-bracketed repeats.
3656  Version 1.02 12-Dec-97  Version 1.02 12-Dec-97
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