X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=lib%2FScalar%2FVec%2FUtil.pm;h=b6e381fe8ac78b2b52411a898ce8e19f4950fb96;hb=088b0bf059b7f80c9e758fde06eb4fc4702c898d;hp=b8d0616fffa4010b1f4357bb76f40438e606f0b3;hpb=38f1e5b7becc37d9c9339c8575c634da68e9166c;p=perl%2Fmodules%2FScalar-Vec-Util.git

diff --git a/lib/Scalar/Vec/Util.pm b/lib/Scalar/Vec/Util.pm
index b8d0616..b6e381f 100644
--- a/lib/Scalar/Vec/Util.pm
+++ b/lib/Scalar/Vec/Util.pm
@@ -72,17 +72,22 @@ Grows C<$vec> if necessary.
 
 =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;
- $x = 1 if $x;
- vec($_[0], $_, 1) = $x for $s .. $s + $l - 1;
+ 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) { # 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 + $l - 1;
+ } else {
+  vec($_[0], $_, 1) = $x for $s .. $s + $l - 1;
+ }
 }
 
 =head2 C<< vcopy $from => $from_start, $to => $to_start, $length >>
@@ -90,13 +95,15 @@ sub vfill_pp {
 Copies C<$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.
 
 =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;
@@ -105,6 +112,72 @@ sub vcopy_pp {
  }
 }
 
+=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<abs $bits> 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.
+
+=cut
+
+sub vshift ($$$$;$) {
+ my ($start, $length, $bits, $insert) = @_[1 .. 4];
+ return unless $length and $bits;
+ croak 'Invalid negative offset' if $start  < 0;
+ croak 'Invalid negative length' if $length < 0;
+ my $left = 1;
+ if ($bits < 0) {
+  $left = 0;
+  $bits = -$bits;
+ }
+ if ($bits < $length) {
+  $length -= $bits;
+  if ($left) {
+   vcopy($_[0], $start, $_[0], $start + $bits, $length);
+   vfill($_[0], $start, $bits, $insert) if defined $insert;
+  } else {
+   vcopy($_[0], $start + $bits, $_[0], $start, $length);
+   vfill($_[0], $start + $length, $bits, $insert) if defined $insert;
+  }
+ } else {
+  vfill($_[0], $start, $length, $insert) if defined $insert;
+ }
+}
+
+=head2 C<< vrot $v, $start, $length, $bits >>
+
+In the area starting at C<$start> and of length C<$length> in C<$v>, rotates bits C<abs $bits> positions left if C<< $bits > 0 >> and right otherwise.
+Bits outside of the specified area are left untouched.
+Currently allocates an extra buffer of size C<O($bits)>.
+
+=cut
+
+sub vrot ($$$$) {
+ 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<$v2> are equal, and false otherwise.
@@ -112,9 +185,10 @@ If needed, C<$length> is decreased to fit inside C<$v1> and C<$v2> boundaries.
 
 =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);
@@ -125,7 +199,7 @@ sub veq_pp {
 
 =head1 EXPORT
 
-The functions L</vfill>, L</vcopy> 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.
@@ -137,7 +211,7 @@ use base qw/Exporter/;
 
 our @EXPORT         = ();
 our %EXPORT_TAGS    = (
- 'funcs'  => [ qw/vfill vcopy veq/ ],
+ 'funcs'  => [ qw/vfill vcopy vshift vrot veq/ ],
  'consts' => [ qw/SVU_PP SVU_SIZE/ ]
 );
 our @EXPORT_OK      = map { @$_ } values %EXPORT_TAGS;
@@ -256,7 +330,7 @@ Tests code coverage report is available at L<http://www.profvince.com/perl/cover
 
 =head1 COPYRIGHT & LICENSE
 
-Copyright 2008 Vincent Pit, all rights reserved.
+Copyright 2008-2009 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.