2 Scalar::Vec::Util - Utility routines for vec strings.
8 use Scalar::Vec::Util qw/vfill vcopy veq/;
11 vfill $s, 0, 100, 1; # Fill with 100 bits 1 starting at 0.
13 vcopy $s, 20, $t, 10, 30; # Copy 30 bits from $s, starting at 20,
14 # to $t, starting at 10.
15 vcopy $t, 10, $t, 20, 30; # Overalapping areas DWIM.
16 if (veq $t, 10, $t, 20, 30) { ... } # Yes, they are equal now.
19 A set of utilities to manipulate bits in vec strings. Highly optimized
20 XS routines are used when available, but straightforward pure perl
21 replacements are also provided for platforms without a C compiler.
23 This module doesn't reimplement bit vectors. It can be used on the very
24 same scalars that "vec" builds, or actually on any Perl string
29 True when pure perl fallbacks are used instead of XS functions.
32 Size in bits of the unit used for moves. The higher this value is, the
33 faster the XS functions are. It's usually "CHAR_BIT *
34 $Config{alignbytes}", except on non-little-endian architectures where it
35 currently falls back to "CHAR_BIT" (e.g. SPARC).
38 "vfill $vec, $start, $length, $bit"
39 Starting at $start in $vec, fills $length bits with $bit. Grows $vec if
42 "vcopy $from => $from_start, $to => $to_start, $length"
43 Copies $length bits starting at $from_start in $from to $to_start in
44 $to. If "$from_start + $length" is too long for $from, zeros are copied
45 past $length. Grows $to if necessary.
47 "veq $v1 => $v1_start, $v2 => $v2_start, $length"
48 Returns true if the $length bits starting at $v1_start in $v1 and
49 $v2_start in $v2 are equal, and false otherwise. If needed, $length is
50 decreased to fit inside $v1 and $v2 boundaries.
53 The functions "vfill", "vcopy" and "veq" are only exported on request.
54 All of them are exported by the tags ':funcs' and ':all'.
56 The constants "SVU_PP" and "SVU_SIZE" are also only exported on request.
57 They are all exported by the tags ':consts' and ':all'.
60 Please report architectures where we can't use the alignment as the move
61 unit. I'll add exceptions for them.
64 Carp, Exporter (core modules since perl 5), XSLoader (since perl 5.006).
67 Bit::Vector gives a complete reimplementation of bit vectors.
70 Vincent Pit, "<perl at profvince.com>", <http://www.profvince.com>.
72 You can contact me by mail or on #perl @ FreeNode (vincent or
76 Please report any bugs or feature requests to "bug-scalar-vec-util at
77 rt.cpan.org", or through the web interface at
78 <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Scalar-Vec-Util>. I will
79 be notified, and then you'll automatically be notified of progress on
80 your bug as I make changes.
83 You can find documentation for this module with the perldoc command.
85 perldoc Scalar::Vec::Util
87 Tests code coverage report is available at
88 <http://www.profvince.com/perl/cover/Scalar-Vec-Util>.
91 Copyright 2008 Vincent Pit, all rights reserved.
93 This program is free software; you can redistribute it and/or modify it
94 under the same terms as Perl itself.