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::UtilTests 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.