-Use pack() and unpack(), or else vec() and the bitwise operations.
-
-For example, this sets $vec to have bit N set if $ints[N] was set:
-
- $vec = '';
- foreach(@ints) { vec($vec,$_,1) = 1 }
-
-Here's how, given a vector in $vec, you can
-get those bits into your @ints array:
-
- sub bitvec_to_list {
- my $vec = shift;
- my @ints;
- # Find null-byte density then select best algorithm
- if ($vec =~ tr/\0// / length $vec > 0.95) {
- use integer;
- my $i;
- # This method is faster with mostly null-bytes
- while($vec =~ /[^\0]/g ) {
- $i = -9 + 8 * pos $vec;
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- push @ints, $i if vec($vec, ++$i, 1);
- }
- } else {
- # This method is a fast general algorithm
- use integer;
- my $bits = unpack "b*", $vec;
- push @ints, 0 if $bits =~ s/^(\d)// && $1;
- push @ints, pos $bits while($bits =~ /1/g);
- }
- return \@ints;
- }
+Use C<pack()> and C<unpack()>, or else C<vec()> and the bitwise
+operations.
+
+For example, this sets C<$vec> to have bit N set if C<$ints[N]> was
+set:
+
+ $vec = '';
+ foreach(@ints) { vec($vec,$_,1) = 1 }
+
+Here's how, given a vector in C<$vec>, you can get those bits into your
+C<@ints> array:
+
+ sub bitvec_to_list {
+ my $vec = shift;
+ my @ints;
+ # Find null-byte density then select best algorithm
+ if ($vec =~ tr/\0// / length $vec > 0.95) {
+ use integer;
+ my $i;
+
+ # This method is faster with mostly null-bytes
+ while($vec =~ /[^\0]/g ) {
+ $i = -9 + 8 * pos $vec;
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ push @ints, $i if vec($vec, ++$i, 1);
+ }
+ }
+ else {
+ # This method is a fast general algorithm
+ use integer;
+ my $bits = unpack "b*", $vec;
+ push @ints, 0 if $bits =~ s/^(\d)// && $1;
+ push @ints, pos $bits while($bits =~ /1/g);
+ }
+
+ return \@ints;
+ }