X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScalar%2FVec%2FUtil.pm;h=a370396bf09651ce46df8b2a2be94b4b331b6005;hb=2a9dee79e2745ec96ce0955559ba2d8116b74526;hp=b5a8080e7f235a1cde6ca7693f59dd9547d92af0;hpb=c36fbc2566b9aeb0642e7a1b2fb8fc843faff3e9;p=perl%2Fmodules%2FScalar-Vec-Util.git diff --git a/lib/Scalar/Vec/Util.pm b/lib/Scalar/Vec/Util.pm index b5a8080..a370396 100644 --- a/lib/Scalar/Vec/Util.pm +++ b/lib/Scalar/Vec/Util.pm @@ -3,7 +3,7 @@ package Scalar::Vec::Util; use strict; use warnings; -use Carp qw/croak/; +use Carp qw; =head1 NAME @@ -11,13 +11,13 @@ Scalar::Vec::Util - Utility routines for vec strings. =head1 VERSION -Version 0.05 +Version 0.07 =cut our $VERSION; BEGIN { - $VERSION = '0.05'; + $VERSION = '0.07'; eval { require XSLoader; XSLoader::load(__PACKAGE__, $VERSION); @@ -33,59 +33,58 @@ BEGIN { =head1 SYNOPSIS - use Scalar::Vec::Util qw/vfill vcopy veq/; + use Scalar::Vec::Util qw; 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. + vcopy $t, 10, $t, 20, 30; # Overlapping areas DWIM. if (veq $t, 10, $t, 20, 30) { ... } # Yes, they are equal now. =head1 DESCRIPTION -A set of utilities to manipulate bits in vec strings. -Highly optimized XS routines are used when available, but straightforward pure perl replacements are also provided for platforms without a C compiler. +This module provides a set of utility routines that efficiently manipulate bits in vec strings. +Highly optimized XS functions are used whenever possible, but straightforward pure Perl replacements are also available for platforms without a C compiler. -This module doesn't reimplement bit vectors. -It can be used on the very same scalars that C builds, or actually on any Perl string (C). +Note that this module does not aim at reimplementing bit vectors : all its functions can be used on any Perl string, just like L. =head1 CONSTANTS =head2 C -True when pure perl fallbacks are used instead of XS functions. +True when pure Perl fallbacks are used instead of XS functions. =head2 C -Size in bits of the unit used for moves. +The size (in bits) of the unit used for bit operations. The higher this value is, the faster the XS functions are. -It's usually C, except on non-little-endian architectures where it currently falls back to C (e.g. SPARC). +It is usually C, except on non-little-endian architectures where it currently falls back to C (e.g. SPARC). =head1 FUNCTIONS -=head2 C +=head2 C -Starting at C<$start> in C<$vec>, fills C<$length> bits with C<$bit>. -Grows C<$vec> if necessary. + vfill $vec, $start, $length, $bit; -=cut +Starting at C<$start> in C<$vec>, fills C<$length> bits with ones if C<$bit> is true and with zeros if C<$bit> is false. -sub _alldef { - for (@_) { return 0 unless defined } - return 1; -} +C<$vec> is upgraded to a string and extended if necessary. +Bits that are outside of the specified area are left untouched. + +=cut -sub vfill_pp { - (undef, my $s, my $l, my $x) = @_; - croak "Invalid argument" unless _alldef @_; +sub vfill_pp ($$$$) { + my ($s, $l, $x) = @_[1 .. 3]; return unless $l; + croak 'Invalid negative offset' if $s < 0; + croak 'Invalid negative length' if $l < 0; $x = ~0 if $x; my $SIZE = 32; my $t = int($s / $SIZE) + 1; my $u = int(($s + $l) / $SIZE); - if ($SIZE * $t < $s + $l and $t <= $u) { + if ($SIZE * $t < $s + $l) { # implies $t <= $u vec($_[0], $_, 1) = $x for $s .. $SIZE * $t - 1; vec($_[0], $_, $SIZE) = $x for $t .. $u - 1; vec($_[0], $_, 1) = $x for $SIZE * $u .. $s + $l - 1; @@ -94,39 +93,58 @@ sub vfill_pp { } } -=head2 C<< vcopy $from => $from_start, $to => $to_start, $length >> +=head2 C + + vcopy $from => $from_start, $to => $to_start, $length; Copies C<$length> bits starting at C<$from_start> in C<$from> to C<$to_start> in C<$to>. -If C<$from_start + $length> is too long for C<$from>, zeros are copied past C<$length>. -Grows C<$to> if necessary. -Doesn't need to allocate any extra memory. + +C<$from> and C<$to> are allowed to be the same scalar, and the given areas can rightfully overlap. + +C<$from> is upgraded to a string if it isn't one already. +If C<$from_start + $length> goes out of the bounds of C<$from>, then the extra bits are treated as zeros. +C<$to> is upgraded to a string and extended if necessary. +The content of C<$from> is not modified, except when it is equal to C<$to>. +Bits that are outside of the specified area are left untouched. + +This function does not need to allocate any extra memory. =cut -sub vcopy_pp { +sub vcopy_pp ($$$$$) { my ($fs, $ts, $l) = @_[1, 3, 4]; - croak "Invalid argument" unless _alldef @_; return unless $l; + croak 'Invalid negative offset' if $fs < 0 or $ts < 0; + croak 'Invalid negative length' if $l < 0; my $step = $ts - $fs; - if ($step <= 0) { + if ($step <= 0) { vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for $fs .. $fs + $l - 1; } else { # There's a risk of overwriting if $_[0] and $_[2] are the same SV. vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for reverse $fs .. $fs + $l - 1; } } -=head2 C<< vshift $v, $start, $length => $bits [, $insert ] >> +=head2 C + + vshift $v, $start, $length => $bits, $insert; In the area starting at C<$start> and of length C<$length> in C<$v>, shift bits C positions left if C<< $bits > 0 >> and right otherwise. -If C<$insert> is defined, also fills the resulting gap with ones if C<$insert> is true and zeros if it's false. -Bits outside of the specified area are left untouched. -Doesn't need to allocate any extra memory. + +When C<$insert> is defined, the resulting gap is also filled with ones if C<$insert> is true and with zeros if C<$insert> is false. + +C<$v> is upgraded to a string if it isn't one already. +If C<$start + $length> goes out of the bounds of C<$v>, then the extra bits are treated as zeros. +Bits that are outside of the specified area are left untouched. + +This function does not need to allocate any extra memory. =cut -sub vshift { +sub vshift ($$$$;$) { my ($start, $length, $bits, $insert) = @_[1 .. 4]; - return unless $bits; + return unless $length and $bits; + croak 'Invalid negative offset' if $start < 0; + croak 'Invalid negative length' if $length < 0; my $left = 1; if ($bits < 0) { $left = 0; @@ -146,16 +164,62 @@ sub vshift { } } -=head2 C<< veq $v1 => $v1_start, $v2 => $v2_start, $length >> +=head2 C + + vrot $v, $start, $length, $bits; + +In the area starting at C<$start> and of length C<$length> in C<$v>, rotates bits C positions left if C<< $bits > 0 >> and right otherwise. + +C<$v> is upgraded to a string if it isn't one already. +If C<$start + $length> goes out of the bounds of C<$v>, then the extra bits are treated as zeros. +Bits that are outside of the specified area are left untouched. + +This function currently allocates an extra buffer of size C. + +=cut + +sub vrot ($$$$) { + my ($start, $length, $bits) = @_[1 .. 3]; + return unless $length and $bits; + croak 'Invalid negative offset' if $start < 0; + croak 'Invalid negative length' if $length < 0; + my $left = 1; + if ($bits < 0) { + $left = 0; + $bits = -$bits; + } + $bits %= $length; + return unless $bits; + $length -= $bits; + my $buf = ''; + if ($left) { + vcopy($_[0], $start + $length, $buf, 0, $bits); + vcopy($_[0], $start, $_[0], $start + $bits, $length); + vcopy($buf, 0, $_[0], $start, $bits); + } else { + vcopy($_[0], $start, $buf, 0, $bits); + vcopy($_[0], $start + $bits, $_[0], $start, $length); + vcopy($buf, 0, $_[0], $start + $length, $bits); + } +} + +=head2 C + + veq $v1 => $v1_start, $v2 => $v2_start, $length; Returns true if the C<$length> bits starting at C<$v1_start> in C<$v1> and C<$v2_start> in C<$v2> are equal, and false otherwise. -If needed, C<$length> is decreased to fit inside C<$v1> and C<$v2> boundaries. + +C<$v1> and C<$v2> are upgraded to strings if they aren't already, but their contents are never modified. +If C<$v1_start + $length> (respectively C<$v2_start + $length>) goes out of the bounds of C<$v1> (respectively C<$v2>), then the extra bits are treated as zeros. + +This function does not need to allocate any extra memory. =cut -sub veq_pp { +sub veq_pp ($$$$$) { my ($s1, $s2, $l) = @_[1, 3, 4]; - croak "Invalid argument" unless _alldef @_; + croak 'Invalid negative offset' if $s1 < 0 or $s2 < 0; + croak 'Invalid negative length' if $l < 0; my $i = 0; while ($i < $l) { return 0 if vec($_[0], $s1 + $i, 1) != vec($_[2], $s2 + $i, 1); @@ -166,7 +230,7 @@ sub veq_pp { =head1 EXPORT -The functions L, L, L and L are only exported on request. +The functions L, L, L, L and L are only exported on request. All of them are exported by the tags C<':funcs'> and C<':all'>. The constants L and L are also only exported on request. @@ -174,12 +238,12 @@ They are all exported by the tags C<':consts'> and C<':all'>. =cut -use base qw/Exporter/; +use base qw; our @EXPORT = (); our %EXPORT_TAGS = ( - 'funcs' => [ qw/vfill vcopy vshift veq/ ], - 'consts' => [ qw/SVU_PP SVU_SIZE/ ] + 'funcs' => [ qw ], + 'consts' => [ qw ] ); our @EXPORT_OK = map { @$_ } values %EXPORT_TAGS; $EXPORT_TAGS{'all'} = [ @EXPORT_OK ]; @@ -270,6 +334,11 @@ I'll add exceptions for them. =head1 DEPENDENCIES +L 5.6. + +A C compiler. +This module may happen to build with a C++ compiler as well, but don't rely on it, as no guarantee is made in this regard. + L, L (core modules since perl 5), L (since perl 5.006). =head1 SEE ALSO @@ -297,7 +366,7 @@ Tests code coverage report is available at L