NAME
    Scalar::Vec::Util - Utility routines for vec strings.

VERSION
    Version 0.02

SYNOPSIS
        use Scalar::Vec::Util qw/vfill vcopy veq/;

        my $s;
        vfill $s, 0, 100, 1; # Fill with 100 bits 1 starting at 0.
        my $t;
        vcopy $s, 20, $t, 10, 30; # Copy 30 bits from $s, starting at 20,
                                  #                to $t, starting at 10.
        vcopy $t, 10, $t, 20, 30; # Overalapping areas DWIM.
        if (veq $t, 10, $t, 20, 30) { ... } # Yes, they are equal now.

DESCRIPTION
    A set of utilities to manipulate bits in vec strings. Highly optimized
    XS routines are used when available, but straightforward pure perl
    replacements are also provided for platforms without a C compiler.

    This module doesn't reimplement bit vectors. It can be used on the very
    same scalars that "vec" builds, or actually on any Perl string
    ("SVt_PV").

CONSTANTS
  "SVU_PP"
    True when pure perl fallbacks are used instead of XS functions.

  "SVU_SIZE"
    Size in bits of the unit used for moves. The higher this value is, the
    faster the XS functions are. It's usually "CHAR_BIT *
    $Config{alignbytes}", except on non-little-endian architectures where it
    currently falls back to "CHAR_BIT" (e.g. SPARC).

FUNCTIONS
  "vfill $vec, $start, $length, $bit"
    Starting at $start in $vec, fills $length bits with $bit. Grows $vec if
    necessary.

  "vcopy $from => $from_start, $to => $to_start, $length"
    Copies $length bits starting at $from_start in $from to $to_start in
    $to. If "$from_start + $length" is too long for $from, zeros are copied
    past $length. Grows $to if necessary.

  "veq $v1 => $v1_start, $v2 => $v2_start, $length"
    Returns true if the $length bits starting at $v1_start in $v1 and
    $v2_start in $v2 are equal, and false otherwise. If needed, $length is
    decreased to fit inside $v1 and $v2 boundaries.

EXPORT
    The functions "vfill", "vcopy" and "veq" are only exported on request.
    All of them are exported by the tags ':funcs' and ':all'.

    The constants "SVU_PP" and "SVU_SIZE" are also only exported on request.
    They are all exported by the tags ':consts' and ':all'.

CAVEATS
    Please report architectures where we can't use the alignment as the move
    unit. I'll add exceptions for them.

DEPENDENCIES
    Carp, Exporter (core modules since perl 5), XSLoader (since perl 5.006).

SEE ALSO
    Bit::Vector gives a complete reimplementation of bit vectors.

AUTHOR
    Vincent Pit, "<perl at profvince.com>", <http://www.profvince.com>.

    You can contact me by mail or on #perl @ FreeNode (vincent or
    Prof_Vince).

BUGS
    Please report any bugs or feature requests to "bug-scalar-vec-util at
    rt.cpan.org", or through the web interface at
    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Scalar-Vec-Util>. I will
    be notified, and then you'll automatically be notified of progress on
    your bug as I make changes.

SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc Scalar::Vec::Util

    Tests code coverage report is available at
    <http://www.profvince.com/perl/cover/Scalar-Vec-Util>.

COPYRIGHT & LICENSE
    Copyright 2008 Vincent Pit, all rights reserved.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.