Rice coding: Difference between revisions
→{{header|raku}}: no need to create a module here
(→{{header|Wren}}: Oops!) |
(→{{header|raku}}: no need to create a module here) |
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=={{header|raku}}==
<syntaxhighlight lang="raku">
our sub encode(Int $n, UInt :$k = 2) {
my $d = 2**$k;
my $q = $n div $d;
my $b = sign(1 + sign($q));
my $m = abs($q) + $b;
flat
$b xx $m, 1 - $b,
($n mod $d).polymod(2 xx $k - 1).reverse
}
our sub decode(@bits is copy, UInt :$k = 2) {▼
my $d = 2**$k;▼
my $b = @bits.shift;▼
my $m = 1;▼
$m++ while @bits and @bits.shift == $b;▼
my $q = $b ?? $m - 1 !! -$m;▼
$q*$d + @bits.reduce(2 * * + *);▼
}
▲our sub decode(@bits is copy, UInt :$k = 2) {
▲ my $d = 2**$k;
▲ my $b = @bits.shift;
▲ my $m = 1;
▲ $m++ while @bits and @bits.shift == $b;
▲ my $q = $b ?? $m - 1 !! -$m;
▲ $q*$d + @bits.reduce(2 * * + *);
}
constant N = 100;
▲ use Test;
plan
▲ is $_, decode encode $_ for -N..N;
=={{header|Wren}}==
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