Rice coding: Difference between revisions
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=={{header|ALGOL 68}}==
{{Trans|Julia|with output formatting similar to the Wren sample and using STRINGs to represent the bit vector}}
<syntaxhighlight lang="algol68">
BEGIN # Rice encoding - translation of the Julia sample #
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100001 -> 17
</pre>
=={{header|FreeBASIC}}==
{{trans|Phix}}
<syntaxhighlight lang="vbnet">Function RiceEncode(n As Integer, k As Integer = 2, extended As Boolean = False) As String
If extended Then n = Iif(n < 0, -2*n-1, 2*n)
Dim As Integer m = 2 ^ k
Dim As Integer q = n \ m
Dim As Integer r = n Mod m
Return String(q, "1") & Right("00000000" & Bin(r), k + 1)
End Function
Function RiceDecode(a As String, k As Integer = 2, extended As Boolean = False) As Integer
Dim As Integer m = 2 ^ k
Dim As Integer q = Instr(a, "0") - 1
Dim As Integer r = Val("&B" & Mid(a, q + 2))
Dim As Integer i = q * m + r
If extended Then i = Iif(i Mod 2, -(i +1) \ 2, i \ 2)
Return i
End Function
Dim As Integer n
Dim As String s
Print "Base Rice Coding:"
For n = 0 To 10
s = RiceEncode(n)
Print Using "& -> & -> &"; n; s; RiceDecode(s)
Next n
Print "Extended Rice Coding:"
For n = -10 To 10
s = RiceEncode(n, 2, True)
Print Using "& -> & -> &"; n; s; RiceDecode(s, 2, True)
Next n
Sleep</syntaxhighlight>
{{out}}
<pre>Same as Phix entry.</pre>
=={{header|Julia}}==
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{{Trans|Julia|Using strings to represent the bit vector}}
<syntaxhighlight lang="lua">
do -- Rice encoding -
-- Golomb-Rice encoding of a positive number to a bit vector (string of 0s and 1s) using M of 2^k
local function rice_encode( n, k )
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k = k or 2
local m = math.floor( 2^k )
local result, q, r = {}, math.floor( n / m ), n % m
result[ #result + 1 ] = r % 2 == 0 and "0" or "1"
r = math.floor( r / 2 )
end
while #result < k do result[ #result + 1 ] = "0" end
result[ #result + 1 ] = "0"
for i = 1, q do result[ #result + 1 ] = "1" end
return string.reverse( table.concat( result, "" ) )
end
-- see wikipedia.org/wiki/Golomb_coding#Use_with_signed_integers
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local function extended_rice_decode( a, k )
k = k or 2
local i = rice_decode( a, k )
return math.floor( i % 2 == 1 and - ( ( i + 1 ) / 2 ) or i / 2 )
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=={{header|Phix}}==
{{trans|Julia}}
<!--(phixonline)-->
<syntaxhighlight lang="phix">
with javascript_semantics
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Then again the above is using strings for demonstration purposes, so that code is hardly production-ready.
=={{header|
{{works with|Python|3.x}}
{{trans|Phix}}
<syntaxhighlight lang="python">#!/usr/bin/python
import math
def rice_encode(n, k = 2, extended = False):
if extended:
n = -2 * n -1 if n < 0 else 2*n
assert n >= 0
m = 2**k
q = n//m
r = n % m
return '1' * q + format(r, '0{}b'.format(k + 1))
def rice_decode(a, k = 2, extended = False):
m = 2**k
q = a.find('0')
r = int(a[q:], 2)
i = (q) * m + r
if extended:
i = -(i+1)//2 if i%2 else i//2
return i
print("Base Rice Coding:")
for n in range(11):
s = rice_encode(n)
print(f"{n} -> {s} -> {rice_decode(s)}")
print("Extended Rice Coding:")
for n in range(-10, 11):
s = rice_encode(n, 2, True)
print(f"{n} -> {s} -> {rice_decode(s, 2, True)}")</syntaxhighlight>
{{out}}
<pre>Same as Phix entry.</pre>
=={{header|Raku}}==
<syntaxhighlight lang="raku">package Rice {
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is $_, Rice::decode Rice::encode $_ for -N..N;
}</syntaxhighlight>
=={{header|Sidef}}==
{{trans|Perl}}
<syntaxhighlight lang="ruby">func rice(k, arr) {
var t = 2**k
arr.map {|v|
['1' * (v >> k), '0', '%0*s' % (k, as_bin(v % t))].join
}.join
}
func derice(k, str) {
gather {
var re = Regex('\G(1*)0(.{' + Str(k) + '})', 'g')
while (str =~ re) {|m|
take((m[0].len << k) + Num(m[1], 2))
}
}
}
for k in (2 .. 6) {
say "\nk = #{k}\n"
var input = @(0..17).shuffle
var enc = rice(k, input)
var dec = derice(k, enc)
say " input: #{input}"
say " rice: #{enc}"
say "decoded: #{dec}"
assert_eq(dec, input)
}</syntaxhighlight>
{{out}}
<pre>
k = 2
input: [5, 6, 15, 17, 3, 9, 4, 10, 12, 2, 11, 0, 1, 13, 7, 16, 8, 14]
rice: 10011010111011111100101111001100011010111000010110110000011110011011111100011000111010
decoded: [5, 6, 15, 17, 3, 9, 4, 10, 12, 2, 11, 0, 1, 13, 7, 16, 8, 14]
k = 3
input: [11, 14, 16, 4, 0, 5, 12, 13, 17, 3, 6, 10, 15, 2, 9, 7, 8, 1]
rice: 100111011011000001000000010110100101011100010011011010010101110010100010111100000001
decoded: [11, 14, 16, 4, 0, 5, 12, 13, 17, 3, 6, 10, 15, 2, 9, 7, 8, 1]
k = 4
input: [6, 4, 2, 9, 0, 5, 1, 3, 17, 15, 10, 11, 16, 13, 8, 14, 7, 12]
rice: 00110001000001001001000000010100001000111000010111101010010111000000110101000011100011101100
decoded: [6, 4, 2, 9, 0, 5, 1, 3, 17, 15, 10, 11, 16, 13, 8, 14, 7, 12]
k = 5
input: [17, 11, 14, 15, 4, 10, 12, 8, 16, 5, 6, 13, 3, 7, 1, 9, 2, 0]
rice: 010001001011001110001111000100001010001100001000010000000101000110001101000011000111000001001001000010000000
decoded: [17, 11, 14, 15, 4, 10, 12, 8, 16, 5, 6, 13, 3, 7, 1, 9, 2, 0]
k = 6
input: [2, 3, 14, 1, 7, 11, 17, 9, 16, 8, 13, 15, 6, 10, 12, 5, 4, 0]
rice: 000001000000110001110000000100001110001011001000100010010010000000100000011010001111000011000010100001100000010100001000000000
decoded: [2, 3, 14, 1, 7, 11, 17, 9, 16, 8, 13, 15, 6, 10, 12, 5, 4, 0]
</pre>
=={{header|Wren}}==
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{{libheader|Wren-check}}
{{libheader|Wren-fmt}}
<syntaxhighlight lang="
import "./check" for Check
import "./fmt" for Fmt
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