ChangeLog for PCRE
------------------

Version 8.12 15-Jan-2011
------------------------

1.  Fixed some typos in the markup of the man pages, and wrote a script that
    checks for such things as part of the documentation building process.

2.  On a big-endian 64-bit system, pcregrep did not correctly process the
    --match-limit and --recursion-limit options (added for 8.11). In
    particular, this made one of the standard tests fail. (The integer value
    went into the wrong half of a long int.)

3.  If the --colour option was given to pcregrep with -v (invert match), it
    did strange things, either producing crazy output, or crashing. It should,
    of course, ignore a request for colour when reporting lines that do not
    match.

4.  Another pcregrep bug caused similar problems if --colour was specified with
    -M (multiline) and the pattern match finished with a line ending.

5.  In pcregrep, when a pattern that ended with a literal newline sequence was
    matched in multiline mode, the following line was shown as part of the
    match. This seems wrong, so I have changed it.

6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
    the check for further matches in the same line (so they could be coloured)
    to overrun the end of the current line. If another match was found, it was
    incorrectly shown (and then shown again when found in the next line).

7.  If pcregrep was compiled under Windows, there was a reference to the
    function pcregrep_exit() before it was defined. I am assuming this was
    the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
    reported by a user. I've moved the definition above the reference.


Version 8.11 10-Dec-2010
------------------------

1.  (*THEN) was not working properly if there were untried alternatives prior
    to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
    backtracked to try for "b" instead of moving to the next alternative branch
    at the same level (in this case, to look for "c"). The Perl documentation
    is clear that when (*THEN) is backtracked onto, it goes to the "next
    alternative in the innermost enclosing group".

2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
    such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
    result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
    (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
    (*THEN).

3.  If \s appeared in a character class, it removed the VT character from
    the class, even if it had been included by some previous item, for example
    in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
    of \s, but is part of the POSIX "space" class.)

4.  A partial match never returns an empty string (because you can always
    match an empty string at the end of the subject); however the checking for
    an empty string was starting at the "start of match" point. This has been
    changed to the "earliest inspected character" point, because the returned
    data for a partial match starts at this character. This means that, for
    example, /(?<=abc)def/ gives a partial match for the subject "abc"
    (previously it gave "no match").

5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
    of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
    previously a full match would be given. However, setting PCRE_PARTIAL_HARD
    has an implication that the given string is incomplete (because a partial
    match is preferred over a full match). For this reason, these items now
    give a partial match in this situation. [Aside: previously, the one case
    /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
    match rather than a full match, which was wrong by the old rules, but is
    now correct.]

6.  There was a bug in the handling of #-introduced comments, recognized when
    PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
    If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
    UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
    scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
    but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
    places in pcre_compile().

7.  Related to (6) above, when pcre_compile() was skipping #-introduced
    comments when looking ahead for named forward references to subpatterns,
    the only newline sequence it recognized was NL. It now handles newlines
    according to the set newline convention.

8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
    former, but used strtoul(), whereas pcretest avoided strtoul() but did not
    cater for a lack of strerror(). These oversights have been fixed.

9.  Added --match-limit and --recursion-limit to pcregrep.

10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.

11. When the -o option was used, pcregrep was setting a return code of 1, even
    when matches were found, and --line-buffered was not being honoured.

12. Added an optional parentheses number to the -o and --only-matching options
    of pcregrep.

13. Imitating Perl's /g action for multiple matches is tricky when the pattern
    can match an empty string. The code to do it in pcretest and pcredemo
    needed fixing:

    (a) When the newline convention was "crlf", pcretest got it wrong, skipping
        only one byte after an empty string match just before CRLF (this case
        just got forgotten; "any" and "anycrlf" were OK).

    (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
        mode when an empty string match preceded an ASCII character followed by
        a non-ASCII character. (The code for advancing by one character rather
        than one byte was nonsense.)

    (c) The pcredemo.c sample program did not have any code at all to handle
        the cases when CRLF is a valid newline sequence.

14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
    as a starting offset was within the subject string. There is now a new
    error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
    negative or greater than the length of the string. In order to test this,
    pcretest is extended to allow the setting of negative starting offsets.

15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
    starting offset points to the beginning of a UTF-8 character was
    unnecessarily clumsy. I tidied it up.

16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
    bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.

17. Nobody had reported that the --include_dir option, which was added in
    release 7.7 should have been called --include-dir (hyphen, not underscore)
    for compatibility with GNU grep. I have changed it to --include-dir, but
    left --include_dir as an undocumented synonym, and the same for
    --exclude-dir, though that is not available in GNU grep, at least as of
    release 2.5.4.

18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
    characters from a string of bytes) have been redefined so as not to use
    loops, in order to improve performance in some environments. At the same
    time, I abstracted some of the common code into auxiliary macros to save
    repetition (this should not affect the compiled code).

19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
    compile-time error is now given if \c is not followed by an ASCII
    character, that is, a byte less than 128. (In EBCDIC mode, the code is
    different, and any byte value is allowed.)

20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
    START_OPTIMIZE option, which is now allowed at compile time - but just
    passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
    to pcregrep and other applications that have no direct access to PCRE
    options. The new /Y option in pcretest sets this option when calling
    pcre_compile().

21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
    back references. Groups containing recursive back references were forced to
    be atomic by that change, but in the case of named groups, the amount of
    memory required was incorrectly computed, leading to "Failed: internal
    error: code overflow". This has been fixed.

22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
    pcretest.c, to avoid build problems in some Borland environments.


Version 8.10 25-Jun-2010
------------------------

1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
    THEN.

2.  (*ACCEPT) was not working when inside an atomic group.

3.  Inside a character class, \B is treated as a literal by default, but
    faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
    causes the error). The code is unchanged, but I tidied the documentation.

4.  Inside a character class, PCRE always treated \R and \X as literals,
    whereas Perl faults them if its -w option is set. I have changed PCRE so
    that it faults them when PCRE_EXTRA is set.

5.  Added support for \N, which always matches any character other than
    newline. (It is the same as "." when PCRE_DOTALL is not set.)

6.  When compiling pcregrep with newer versions of gcc which may have
    FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
    declared with attribute warn_unused_result" were given. Just casting the
    result to (void) does not stop the warnings; a more elaborate fudge is
    needed. I've used a macro to implement this.

7.  Minor change to pcretest.c to avoid a compiler warning.

8.  Added four artifical Unicode properties to help with an option to make
    \s etc use properties (see next item). The new properties are: Xan
    (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).

9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
    use Unicode properties. (*UCP) at the start of a pattern can be used to set
    this option. Modified pcretest to add /W to test this facility. Added
    REG_UCP to make it available via the POSIX interface.

10. Added --line-buffered to pcregrep.

11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
    studied, and the match started with a letter with a code point greater than
    127 whose first byte was different to the first byte of the other case of
    the letter, the other case of this starting letter was not recognized
    (#976).

12. If a pattern that was studied started with a repeated Unicode property
    test, for example, \p{Nd}+, there was the theoretical possibility of
    setting up an incorrect bitmap of starting bytes, but fortunately it could
    not have actually happened in practice until change 8 above was made (it
    added property types that matched character-matching opcodes).

13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
    possible starting bytes for non-anchored patterns.

14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
    \R, and also a number of cases that involve Unicode properties, both
    explicit and implicit when PCRE_UCP is set.

15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
    input, it could crash or give wrong results if characters with values
    greater than 0xc0 were present in the subject string. (Detail: it assumed
    UTF-8 input when processing these items.)

16. Added a lot of (int) casts to avoid compiler warnings in systems where
    size_t is 64-bit (#991).

17. Added a check for running out of memory when PCRE is compiled with
    --disable-stack-for-recursion (#990).

18. If the last data line in a file for pcretest does not have a newline on
    the end, a newline was missing in the output.

19. The default pcre_chartables.c file recognizes only ASCII characters (values
    less than 128) in its various bitmaps. However, there is a facility for
    generating tables according to the current locale when PCRE is compiled. It
    turns out that in some environments, 0x85 and 0xa0, which are Unicode space
    characters, are recognized by isspace() and therefore were getting set in
    these tables, and indeed these tables seem to approximate to ISO 8859. This
    caused a problem in UTF-8 mode when pcre_study() was used to create a list
    of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
    which of course cannot start UTF-8 characters. I have changed the code so
    that only real ASCII characters (less than 128) and the correct starting
    bytes for UTF-8 encodings are set for characters greater than 127 when in
    UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
    altogether.)

20. Added the /T option to pcretest so as to be able to run tests with non-
    standard character tables, thus making it possible to include the tests
    used for 19 above in the standard set of tests.

21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
    reference to a subpattern the other side of a comment that contains an
    opening parenthesis caused either an internal compiling error, or a
    reference to the wrong subpattern.


Version 8.02 19-Mar-2010
------------------------

1.  The Unicode data tables have been updated to Unicode 5.2.0.

2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
    configured.

3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
    original author of that file, following a query about its status.

4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
    inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.

5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
    quantifier applied to a forward-referencing subroutine call, could compile
    incorrect code or give the error "internal error: previously-checked
    referenced subpattern not found".

6.  Both MS Visual Studio and Symbian OS have problems with initializing
    variables to point to external functions. For these systems, therefore,
    pcre_malloc etc. are now initialized to local functions that call the
    relevant global functions.

7.  There were two entries missing in the vectors called coptable and poptable
    in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
    I've fixed the data, and added a kludgy way of testing at compile time that
    the lengths are correct (equal to the number of opcodes).

8.  Following on from 7, I added a similar kludge to check the length of the
    eint vector in pcreposix.c.

9.  Error texts for pcre_compile() are held as one long string to avoid too
    much relocation at load time. To find a text, the string is searched,
    counting zeros. There was no check for running off the end of the string,
    which could happen if a new error number was added without updating the
    string.

10. \K gave a compile-time error if it appeared in a lookbehind assersion.

11. \K was not working if it appeared in an atomic group or in a group that
    was called as a "subroutine", or in an assertion. Perl 5.11 documents that
    \K is "not well defined" if used in an assertion. PCRE now accepts it if
    the assertion is positive, but not if it is negative.

12. Change 11 fortuitously reduced the size of the stack frame used in the
    "match()" function of pcre_exec.c by one pointer. Forthcoming
    implementation of support for (*MARK) will need an extra pointer on the
    stack; I have reserved it now, so that the stack frame size does not
    decrease.

13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
    item in branch that calls a recursion is a subroutine call - as in the
    second branch in the above example - was incorrectly given the compile-
    time error "recursive call could loop indefinitely" because pcre_compile()
    was not correctly checking the subroutine for matching a non-empty string.

14. The checks for overrunning compiling workspace could trigger after an
    overrun had occurred. This is a "should never occur" error, but it can be
    triggered by pathological patterns such as hundreds of nested parentheses.
    The checks now trigger 100 bytes before the end of the workspace.

15. Fix typo in configure.ac: "srtoq" should be "strtoq".


Version 8.01 19-Jan-2010
------------------------

1.  If a pattern contained a conditional subpattern with only one branch (in
    particular, this includes all (*DEFINE) patterns), a call to pcre_study()
    computed the wrong minimum data length (which is of course zero for such
    subpatterns). This could cause incorrect "no match" results.

2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
    the pattern is reset in the first branch, pcre_compile() failed with
    "internal error: code overflow at offset...". This happened only when
    the reset was to the original external option setting. (An optimization
    abstracts leading options settings into an external setting, which was the
    cause of this.)

3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
    of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
    assertion pattern did not match (meaning that the assertion was true), it
    was incorrectly treated as false if the SKIP had been reached during the
    matching. This also applied to assertions used as conditions.

4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
    assertion subpattern, including such a pattern used as a condition,
    unpredictable results occurred, instead of the error return
    PCRE_ERROR_DFA_UITEM.

5.  The C++ GlobalReplace function was not working like Perl for the special
    situation when an empty string is matched. It now does the fancy magic
    stuff that is necessary.

6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
    removed. (These were left over from very, very early versions of PCRE.)

7.  Some cosmetic changes to the code to make life easier when compiling it
    as part of something else:

    (a) Change DEBUG to PCRE_DEBUG.

    (b) In pcre_compile(), rename the member of the "branch_chain" structure
        called "current" as "current_branch", to prevent a collision with the
        Linux macro when compiled as a kernel module.

    (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
        prevent a collision with the Linux macro when compiled as a kernel
        module.

8.  In pcre_compile() there are some checks for integer overflows that used to
    cast potentially large values to (double). This has been changed to that
    when building, a check for int64_t is made, and if it is found, it is used
    instead, thus avoiding the use of floating point arithmetic. (There is no
    other use of FP in PCRE.) If int64_t is not found, the fallback is to
    double.

9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
    2005 (difference between two addresses compared to an unsigned value).

10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
    custom one, because of the following reported problem in Windows:

      - libbz2 uses the Pascal calling convention (WINAPI) for the functions
          under Win32.
      - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
          therefore missing the function definition.
      - The compiler thus generates a "C" signature for the test function.
      - The linker fails to find the "C" function.
      - PCRE fails to configure if asked to do so against libbz2.

11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
    messages were output:

      Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
      rerunning libtoolize, to keep the correct libtool macros in-tree.
      Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.

    I have done both of these things.

12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
    most of the time, it *can* run out if it is given a pattern that contains a
    runaway infinite recursion. I updated the discussion in the pcrestack man
    page.

13. Now that we have gone to the x.xx style of version numbers, the minor
    version may start with zero. Using 08 or 09 is a bad idea because users
    might check the value of PCRE_MINOR in their code, and 08 or 09 may be
    interpreted as invalid octal numbers. I've updated the previous comment in
    configure.ac, and also added a check that gives an error if 08 or 09 are
    used.

14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
    causing partial matching to fail when the end of the subject matched \W
    in a UTF-8 pattern where \W was quantified with a minimum of 3.

15. There were some discrepancies between the declarations in pcre_internal.h
    of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
    their definitions. The declarations used "const uschar *" and the
    definitions used USPTR. Even though USPTR is normally defined as "const
    unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
    reported that: "This difference in casting confuses some C++ compilers, for
    example, SunCC recognizes above declarations as different functions and
    generates broken code for hbpcre." I have changed the declarations to use
    USPTR.

16. GNU libtool is named differently on some systems. The autogen.sh script now
    tries several variants such as glibtoolize (MacOSX) and libtoolize1x
    (FreeBSD).

17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
    (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
    comment: "Figure out how to create a longlong from a string: strtoll and
    equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
    instance, but it only takes 2 args instead of 3!"

18. A subtle bug concerned with back references has been fixed by a change of
    specification, with a corresponding code fix. A pattern such as
    ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
    refers, was giving matches when it shouldn't. For example, xa=xaaa would
    match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
    same bug. Such groups have to be quantified to be useful, or contained
    inside another quantified group. (If there's no repetition, the reference
    can never match.) The problem arises because, having left the group and
    moved on to the rest of the pattern, a later failure that backtracks into
    the group uses the captured value from the final iteration of the group
    rather than the correct earlier one. I have fixed this in PCRE by forcing
    any group that contains a reference to itself to be an atomic group; that
    is, there cannot be any backtracking into it once it has completed. This is
    similar to recursive and subroutine calls.


Version 8.00 19-Oct-09
----------------------

1.  The table for translating pcre_compile() error codes into POSIX error codes
    was out-of-date, and there was no check on the pcre_compile() error code
    being within the table. This could lead to an OK return being given in
    error.

2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
    "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
    in a Windows environment.

3.  The pcregrep --count option prints the count for each file even when it is
    zero, as does GNU grep. However, pcregrep was also printing all files when
    --files-with-matches was added. Now, when both options are given, it prints
    counts only for those files that have at least one match. (GNU grep just
    prints the file name in this circumstance, but including the count seems
    more useful - otherwise, why use --count?) Also ensured that the
    combination -clh just lists non-zero counts, with no names.

4.  The long form of the pcregrep -F option was incorrectly implemented as
    --fixed_strings instead of --fixed-strings. This is an incompatible change,
    but it seems right to fix it, and I didn't think it was worth preserving
    the old behaviour.

5.  The command line items --regex=pattern and --regexp=pattern were not
    recognized by pcregrep, which required --regex pattern or --regexp pattern
    (with a space rather than an '='). The man page documented the '=' forms,
    which are compatible with GNU grep; these now work.

6.  No libpcreposix.pc file was created for pkg-config; there was just
    libpcre.pc and libpcrecpp.pc. The omission has been rectified.

7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
    when UCP support is not needed, by modifying the Python script that
    generates it from Unicode data files. This should not matter if the module
    is correctly used as a library, but I received one complaint about 50K of
    unwanted data. My guess is that the person linked everything into his
    program rather than using a library. Anyway, it does no harm.

8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
    was a minimum greater than 1 for a wide character in a possessive
    repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
    which had an unlimited repeat of a nested, fixed maximum repeat of a wide
    character. Chaos in the form of incorrect output or a compiling loop could
    result.

9.  The restrictions on what a pattern can contain when partial matching is
    requested for pcre_exec() have been removed. All patterns can now be
    partially matched by this function. In addition, if there are at least two
    slots in the offset vector, the offset of the earliest inspected character
    for the match and the offset of the end of the subject are set in them when
    PCRE_ERROR_PARTIAL is returned.

10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
    synonymous with PCRE_PARTIAL, for backwards compatibility, and
    PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
    and may be more useful for multi-segment matching.

11. Partial matching with pcre_exec() is now more intuitive. A partial match
    used to be given if ever the end of the subject was reached; now it is
    given only if matching could not proceed because another character was
    needed. This makes a difference in some odd cases such as Z(*FAIL) with the
    string "Z", which now yields "no match" instead of "partial match". In the
    case of pcre_dfa_exec(), "no match" is given if every matching path for the
    final character ended with (*FAIL).

12. Restarting a match using pcre_dfa_exec() after a partial match did not work
    if the pattern had a "must contain" character that was already found in the
    earlier partial match, unless partial matching was again requested. For
    example, with the pattern /dog.(body)?/, the "must contain" character is
    "g". If the first part-match was for the string "dog", restarting with
    "sbody" failed. This bug has been fixed.

13. The string returned by pcre_dfa_exec() after a partial match has been
    changed so that it starts at the first inspected character rather than the
    first character of the match. This makes a difference only if the pattern
    starts with a lookbehind assertion or \b or \B (\K is not supported by
    pcre_dfa_exec()). It's an incompatible change, but it makes the two
    matching functions compatible, and I think it's the right thing to do.

14. Added a pcredemo man page, created automatically from the pcredemo.c file,
    so that the demonstration program is easily available in environments where
    PCRE has not been installed from source.

15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
    libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
    library.

16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
    It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
    is not the first non-POSIX option to be added. Clearly some people find
    these options useful.

17. If a caller to the POSIX matching function regexec() passes a non-zero
    value for nmatch with a NULL value for pmatch, the value of
    nmatch is forced to zero.

18. RunGrepTest did not have a test for the availability of the -u option of
    the diff command, as RunTest does. It now checks in the same way as
    RunTest, and also checks for the -b option.

19. If an odd number of negated classes containing just a single character
    interposed, within parentheses, between a forward reference to a named
    subpattern and the definition of the subpattern, compilation crashed with
    an internal error, complaining that it could not find the referenced
    subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
    [The bug was that it was starting one character too far in when skipping
    over the character class, thus treating the ] as data rather than
    terminating the class. This meant it could skip too much.]

20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
    /g option in pcretest when the pattern contains \K, which makes it possible
    to have an empty string match not at the start, even when the pattern is
    anchored. Updated pcretest and pcredemo to use this option.

21. If the maximum number of capturing subpatterns in a recursion was greater
    than the maximum at the outer level, the higher number was returned, but
    with unset values at the outer level. The correct (outer level) value is
    now given.

22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
    PCRE did not set those parentheses (unlike Perl). I have now found a way to
    make it do so. The string so far is captured, making this feature
    compatible with Perl.

23. The tests have been re-organized, adding tests 11 and 12, to make it
    possible to check the Perl 5.10 features against Perl 5.10.

24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
    pattern matches a fixed length string. PCRE did not allow this; now it
    does. Neither allows recursion.

25. I finally figured out how to implement a request to provide the minimum
    length of subject string that was needed in order to match a given pattern.
    (It was back references and recursion that I had previously got hung up
    on.) This code has now been added to pcre_study(); it finds a lower bound
    to the length of subject needed. It is not necessarily the greatest lower
    bound, but using it to avoid searching strings that are too short does give
    some useful speed-ups. The value is available to calling programs via
    pcre_fullinfo().

26. While implementing 25, I discovered to my embarrassment that pcretest had
    not been passing the result of pcre_study() to pcre_dfa_exec(), so the
    study optimizations had never been tested with that matching function.
    Oops. What is worse, even when it was passed study data, there was a bug in
    pcre_dfa_exec() that meant it never actually used it. Double oops. There
    were also very few tests of studied patterns with pcre_dfa_exec().

27. If (?| is used to create subpatterns with duplicate numbers, they are now
    allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
    on the other side of the coin, they are no longer allowed to have different
    names, because these cannot be distinguished in PCRE, and this has caused
    confusion. (This is a difference from Perl.)

28. When duplicate subpattern names are present (necessarily with different
    numbers, as required by 27 above), and a test is made by name in a
    conditional pattern, either for a subpattern having been matched, or for
    recursion in such a pattern, all the associated numbered subpatterns are
    tested, and the overall condition is true if the condition is true for any
    one of them. This is the way Perl works, and is also more like the way
    testing by number works.


Version 7.9 11-Apr-09
---------------------

1.  When building with support for bzlib/zlib (pcregrep) and/or readline
    (pcretest), all targets were linked against these libraries. This included
    libpcre, libpcreposix, and libpcrecpp, even though they do not use these
    libraries. This caused unwanted dependencies to be created. This problem
    has been fixed, and now only pcregrep is linked with bzlib/zlib and only
    pcretest is linked with readline.

2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
    "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
    moved outside it again, because FALSE and TRUE are already defined in AIX,
    but BOOL is not.

3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
    PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.

4.  The pcregrep documentation said spaces were inserted as well as colons (or
    hyphens) following file names and line numbers when outputting matching
    lines. This is not true; no spaces are inserted. I have also clarified the
    wording for the --colour (or --color) option.

5.  In pcregrep, when --colour was used with -o, the list of matching strings
    was not coloured; this is different to GNU grep, so I have changed it to be
    the same.

6.  When --colo(u)r was used in pcregrep, only the first matching substring in
    each matching line was coloured. Now it goes on to look for further matches
    of any of the test patterns, which is the same behaviour as GNU grep.

7.  A pattern that could match an empty string could cause pcregrep to loop; it
    doesn't make sense to accept an empty string match in pcregrep, so I have
    locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
    seems to be how GNU grep behaves.

8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
    start or after a newline", because the conditional assertion was not being
    correctly handled. The rule now is that both the assertion and what follows
    in the first alternative must satisfy the test.

9.  If auto-callout was enabled in a pattern with a conditional group whose
    condition was an assertion, PCRE could crash during matching, both with
    pcre_exec() and pcre_dfa_exec().

10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
    used for matching.

11. Unicode property support in character classes was not working for
    characters (bytes) greater than 127 when not in UTF-8 mode.

12. Added the -M command line option to pcretest.

14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.

15. Added the PCRE_NO_START_OPTIMIZE match-time option.

16. Added comments and documentation about mis-use of no_arg in the C++
    wrapper.

17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
    from Martin Jerabek that uses macro names for all relevant character and
    string constants.

18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
    SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
    SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
    these, but not everybody uses configure.

19. A conditional group that had only one branch was not being correctly
    recognized as an item that could match an empty string. This meant that an
    enclosing group might also not be so recognized, causing infinite looping
    (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
    with the subject "ab", where knowledge that the repeated group can match
    nothing is needed in order to break the loop.

20. If a pattern that was compiled with callouts was matched using pcre_dfa_
    exec(), but without supplying a callout function, matching went wrong.

21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
    leak if the size of the offset vector was greater than 30. When the vector
    is smaller, the saved offsets during recursion go onto a local stack
    vector, but for larger vectors malloc() is used. It was failing to free
    when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
    error, in fact).

22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
    heapframe that is used only when UTF-8 support is enabled. This caused no
    problem, but was untidy.

23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
    CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
    included within another project.

24. Steven Van Ingelgem's patches to add more options to the CMake support,
    slightly modified by me:

      (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
          not building pcregrep.

      (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
          if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.

25. Forward references, both numeric and by name, in patterns that made use of
    duplicate group numbers, could behave incorrectly or give incorrect errors,
    because when scanning forward to find the reference group, PCRE was not
    taking into account the duplicate group numbers. A pattern such as
    ^X(?3)(a)(?|(b)|(q))(Y) is an example.

26. Changed a few more instances of "const unsigned char *" to USPTR, making
    the feature of a custom pointer more persuasive (as requested by a user).

27. Wrapped the definitions of fileno and isatty for Windows, which appear in
    pcretest.c, inside #ifndefs, because it seems they are sometimes already
    pre-defined.

28. Added support for (*UTF8) at the start of a pattern.

29. Arrange for flags added by the "release type" setting in CMake to be shown
    in the configuration summary.


Version 7.8 05-Sep-08
---------------------

1.  Replaced UCP searching code with optimized version as implemented for Ad
    Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
    stage table and inline lookup instead of a function, giving speed ups of 2
    to 5 times on some simple patterns that I tested. Permission was given to
    distribute the MultiStage2.py script that generates the tables (it's not in
    the tarball, but is in the Subversion repository).

2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
    scripts.

3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
    a group with a zero qualifier. The result of the study could be incorrect,
    or the function might crash, depending on the pattern.

4.  Caseless matching was not working for non-ASCII characters in back
    references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
    It now works when Unicode Property Support is available.

5.  In pcretest, an escape such as \x{de} in the data was always generating
    a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
    non-UTF-8 mode. If the value is greater than 255, it gives a warning about
    truncation.

6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).

7.  Added two (int) casts to pcregrep when printing the difference of two
    pointers, in case they are 64-bit values.

8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
    test 2 if it fails.

9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
    and a #define of that name to empty if it is not externally set. This is to
    allow users of MSVC to set it if necessary.

10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
    the convenience functions in the pcre_get.c source file.

11. An option change at the start of a pattern that had top-level alternatives
    could cause overwriting and/or a crash. This command provoked a crash in
    some environments:

      printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest

    This potential security problem was recorded as CVE-2008-2371.

12. For a pattern where the match had to start at the beginning or immediately
    after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
    pcre_dfa_exec() could read past the end of the passed subject if there was
    no match. To help with detecting such bugs (e.g. with valgrind), I modified
    pcretest so that it places the subject at the end of its malloc-ed buffer.

13. The change to pcretest in 12 above threw up a couple more cases when pcre_
    exec() might read past the end of the data buffer in UTF-8 mode.

14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
    the data contained the byte 0x85 as part of a UTF-8 character within its
    first line. This applied both to normal and DFA matching.

15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
    /^[^d]*?$/8 failed to match "abc".

16. Added a missing copyright notice to pcrecpp_internal.h.

17. Make it more clear in the documentation that values returned from
    pcre_exec() in ovector are byte offsets, not character counts.

18. Tidied a few places to stop certain compilers from issuing warnings.

19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
    supplied by Stefan Weber. I made a further small update for 7.8 because
    there is a change of source arrangements: the pcre_searchfuncs.c module is
    replaced by pcre_ucd.c.


Version 7.7 07-May-08
---------------------

1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
    a string to a long long, pretend we don't even have a long long." This is
    done by checking for the strtoq, strtoll, and _strtoi64 functions.

2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
    pre-7.6 versions, which defined a global no_arg variable instead of putting
    it in the RE class. (See also #8 below.)

3.  Remove a line of dead code, identified by coverity and reported by Nuno
    Lopes.

4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:

    (1) The include/exclude patterns were being applied to the whole pathnames
        of files, instead of just to the final components.

    (2) If there was more than one level of directory, the subdirectories were
        skipped unless they satisfied the include/exclude conditions. This is
        inconsistent with GNU grep (and could even be seen as contrary to the
        pcregrep specification - which I improved to make it absolutely clear).
        The action now is always to scan all levels of directory, and just
        apply the include/exclude patterns to regular files.

5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
    --exclude_dir in the tests to avoid scanning .svn directories.

6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
    NUL character as backslash + 0 rather than backslash + NUL, because PCRE
    doesn't support NULs in patterns.

7.  Added some missing "const"s to declarations of static tables in
    pcre_compile.c and pcre_dfa_exec.c.

8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
    caused by fix #2  above. (Subsequently also a second patch to fix the
    first patch. And a third patch - this was a messy problem.)

9.  Applied Craig's patch to remove the use of push_back().

10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
    matching function regexec().

11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
    which, however, unlike Perl's \g{...}, are subroutine calls, not back
    references. PCRE supports relative numbers with this syntax (I don't think
    Oniguruma does).

12. Previously, a group with a zero repeat such as (...){0} was completely
    omitted from the compiled regex. However, this means that if the group
    was called as a subroutine from elsewhere in the pattern, things went wrong
    (an internal error was given). Such groups are now left in the compiled
    pattern, with a new opcode that causes them to be skipped at execution
    time.

13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
    to the way PCRE behaves:

    (a) A lone ] character is dis-allowed (Perl treats it as data).

    (b) A back reference to an unmatched subpattern matches an empty string
        (Perl fails the current match path).

    (c) A data ] in a character class must be notated as \] because if the
        first data character in a class is ], it defines an empty class. (In
        Perl it is not possible to have an empty class.) The empty class []
        never matches; it forces failure and is equivalent to (*FAIL) or (?!).
        The negative empty class [^] matches any one character, independently
        of the DOTALL setting.

14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
    non-existent subpattern following a character class starting with ']' and
    containing () gave an internal compiling error instead of "reference to
    non-existent subpattern". Fortunately, when the pattern did exist, the
    compiled code was correct. (When scanning forwards to check for the
    existencd of the subpattern, it was treating the data ']' as terminating
    the class, so got the count wrong. When actually compiling, the reference
    was subsequently set up correctly.)

15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
    it was being rejected as not supported by pcre_dfa_exec(), even though
    other assertions are supported. I have made pcre_dfa_exec() support
    (*FAIL).

16. The implementation of 13c above involved the invention of a new opcode,
    OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
    cannot be changed at match time, I realized I could make a small
    improvement to matching performance by compiling OP_ALLANY instead of
    OP_ANY for "." when DOTALL was set, and then removing the runtime tests
    on the OP_ANY path.

17. Compiling pcretest on Windows with readline support failed without the
    following two fixes: (1) Make the unistd.h include conditional on
    HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.

18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
    ncurses library to be included for pcretest when ReadLine support is
    requested, but also to allow for it to be overridden. This patch came from
    Daniel Bergström.

19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
    as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
    any errors with the current Unicode tables. Thanks to Peter Kankowski for
    spotting this.


Version 7.6 28-Jan-08
---------------------

1.  A character class containing a very large number of characters with
    codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
    overflow.

2.  Patch to cut out the "long long" test in pcrecpp_unittest when
    HAVE_LONG_LONG is not defined.

3.  Applied Christian Ehrlicher's patch to update the CMake build files to
    bring them up to date and include new features. This patch includes:

    - Fixed PH's badly added libz and libbz2 support.
    - Fixed a problem with static linking.
    - Added pcredemo. [But later removed - see 7 below.]
    - Fixed dftables problem and added an option.
    - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
        HAVE_LONG_LONG.
    - Added readline support for pcretest.
    - Added an listing of the option settings after cmake has run.

4.  A user submitted a patch to Makefile that makes it easy to create
    "pcre.dll" under mingw when using Configure/Make. I added stuff to
    Makefile.am that cause it to include this special target, without
    affecting anything else. Note that the same mingw target plus all
    the other distribution libraries and programs are now supported
    when configuring with CMake (see 6 below) instead of with
    Configure/Make.

5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
    This is an attempt to solve the reported problem "pcrecpp::no_arg is not
    exported in the Windows port". It has not yet been confirmed that the patch
    solves the problem, but it does no harm.

6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
    NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
    with CMake, and also correct the comment about stack recursion.

7.  Remove the automatic building of pcredemo from the ./configure system and
    from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
    of a program that users should build themselves after PCRE is installed, so
    building it automatically is not really right. What is more, it gave
    trouble in some build environments.

8.  Further tidies to CMakeLists.txt from Sheri and Christian.


Version 7.5 10-Jan-08
---------------------

1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
    values in parens when parsing an RE using the C++ wrapper."

2.  Negative specials like \S did not work in character classes in UTF-8 mode.
    Characters greater than 255 were excluded from the class instead of being
    included.

3.  The same bug as (2) above applied to negated POSIX classes such as
    [:^space:].

4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
    defined or documented. It seems to have been a typo for PCRE_STATIC, so
    I have changed it.

5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
    first named subpattern) and a construct such as (?&a) would reference the
    first named subpattern whose name started with "a" (in other words, the
    length check was missing). Both these problems are fixed. "Subpattern name
    expected" is now given for (?&) (a zero-length name), and this patch also
    makes it give the same error for \k'' (previously it complained that that
    was a reference to a non-existent subpattern).

