=cut
-sub _alldef {
- for (@_) { return 0 unless defined }
- return 1;
-}
-
-sub vfill_pp {
- (undef, my $s, my $l, my $x) = @_;
- croak "Invalid argument" unless _alldef @_;
+sub vfill_pp ($$$$) {
+ my ($s, $l, $x) = @_[1 .. 3];
return unless $l;
+ croak 'Invalid negative offset' if $s < 0;
+ croak 'Invalid negative length' if $l < 0;
$x = ~0 if $x;
my $SIZE = 32;
my $t = int($s / $SIZE) + 1;
my $u = int(($s + $l) / $SIZE);
- if ($SIZE * $t < $s + $l and $t <= $u) {
+ if ($SIZE * $t < $s + $l) { # implies $t <= $u
vec($_[0], $_, 1) = $x for $s .. $SIZE * $t - 1;
vec($_[0], $_, $SIZE) = $x for $t .. $u - 1;
vec($_[0], $_, 1) = $x for $SIZE * $u .. $s + $l - 1;
=cut
-sub vcopy_pp {
+sub vcopy_pp ($$$$$) {
my ($fs, $ts, $l) = @_[1, 3, 4];
- croak "Invalid argument" unless _alldef @_;
return unless $l;
+ croak 'Invalid negative offset' if $fs < 0 or $ts < 0;
+ croak 'Invalid negative length' if $l < 0;
my $step = $ts - $fs;
if ($step <= 0) {
vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for $fs .. $fs + $l - 1;
=cut
-sub vshift {
+sub vshift ($$$$;$) {
my ($start, $length, $bits, $insert) = @_[1 .. 4];
- return unless $bits;
+ return unless $length and $bits;
+ croak 'Invalid negative offset' if $start < 0;
+ croak 'Invalid negative length' if $length < 0;
my $left = 1;
if ($bits < 0) {
$left = 0;
}
}
+=head2 C<< vrot $v, $start, $length, $bits >>
+
+In the area starting at C<$start> and of length C<$length> in C<$v>, rotates bits C<abs $bits> positions left if C<< $bits > 0 >> and right otherwise.
+Bits outside of the specified area are left untouched.
+Currently allocates an extra buffer of size C<O($bits)>.
+
+=cut
+
+sub vrot ($$$$) {
+ my ($start, $length, $bits) = @_[1 .. 3];
+ return unless $length and $bits;
+ croak 'Invalid negative offset' if $start < 0;
+ croak 'Invalid negative length' if $length < 0;
+ my $left = 1;
+ if ($bits < 0) {
+ $left = 0;
+ $bits = -$bits;
+ }
+ $bits %= $length;
+ return unless $bits;
+ $length -= $bits;
+ my $buf = '';
+ if ($left) {
+ vcopy($_[0], $start + $length, $buf, 0, $bits);
+ vcopy($_[0], $start, $_[0], $start + $bits, $length);
+ vcopy($buf, 0, $_[0], $start, $bits);
+ } else {
+ vcopy($_[0], $start, $buf, 0, $bits);
+ vcopy($_[0], $start + $bits, $_[0], $start, $length);
+ vcopy($buf, 0, $_[0], $start + $length, $bits);
+ }
+}
+
=head2 C<< veq $v1 => $v1_start, $v2 => $v2_start, $length >>
Returns true if the C<$length> bits starting at C<$v1_start> in C<$v1> and C<$v2_start> in C<$v2> are equal, and false otherwise.
=cut
-sub veq_pp {
+sub veq_pp ($$$$$) {
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 + $i, 1);
=head1 EXPORT
-The functions L</vfill>, L</vcopy>, L</vshift> and L</veq> are only exported on request.
+The functions L</vfill>, L</vcopy>, L</vshift>, L</vrot> and L</veq> are only exported on request.
All of them are exported by the tags C<':funcs'> and C<':all'>.
The constants L</SVU_PP> and L</SVU_SIZE> are also only exported on request.
our @EXPORT = ();
our %EXPORT_TAGS = (
- 'funcs' => [ qw/vfill vcopy vshift veq/ ],
+ 'funcs' => [ qw/vfill vcopy vshift vrot veq/ ],
'consts' => [ qw/SVU_PP SVU_SIZE/ ]
);
our @EXPORT_OK = map { @$_ } values %EXPORT_TAGS;