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Rewrite AlphabetSize.BitsPerSymbol to use Log2 utility class

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This commit is contained in:
chylex 2019-10-20 06:40:37 +02:00
parent 79a96735a5
commit 87011bc853
3 changed files with 23 additions and 27 deletions
BrotliLib
Brotli/Components/Header
HuffmanTree.Type.Simple.cs
Numbers
AlphabetSize.cs
UnitTests/Numbers
TestAlphabetSize.fs

4
BrotliLib/Brotli/Components/Header/HuffmanTree.Type.Simple.cs
View File

@ -12,7 +12,7 @@ namespace BrotliLib.Brotli.Components.Header{
private static readonly BitDeserializer<HuffmanTree<T>, Context> SimpleCodeDeserialize = MarkedBitDeserializer.Wrap<HuffmanTree<T>, Context>(
(reader, context) => {
byte bitsPerSymbol = context.AlphabetSize.BitsPerSymbol;
int bitsPerSymbol = context.AlphabetSize.BitsPerSymbol;
int symbolCount = reader.NextChunk(2, "NSYM", value => 1 + value);
T[] symbols = reader.ReadValueArray(symbolCount, "symbol", () => context.BitsToSymbol(reader.NextChunk(bitsPerSymbol)));
@ -24,7 +24,7 @@ namespace BrotliLib.Brotli.Components.Header{
);
private static readonly BitSerializer<HuffmanTree<T>, Context> SimpleCodeSerialize = (writer, obj, context) => {
byte bitsPerSymbol = context.AlphabetSize.BitsPerSymbol;
int bitsPerSymbol = context.AlphabetSize.BitsPerSymbol;
writer.WriteChunk(2, obj.Root.SymbolCount - 1);

12
BrotliLib/Numbers/AlphabetSize.cs
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@ -8,17 +8,13 @@ namespace BrotliLib.Numbers{
/// <summary>
/// Returns the minimum amount of bits required to represent every symbol in the alphabet.
/// </summary>
public byte BitsPerSymbol{
public int BitsPerSymbol{
get{
int size = SymbolCount - 1;
byte bitsPerSymbol = 0;
while(size > 0){
size >>= 1;
++bitsPerSymbol;
if (SymbolCount <= 1){
return 0;
}
return bitsPerSymbol;
return Log2.Floor(SymbolCount - 1) + 1;
}
}

34
UnitTests/Numbers/TestAlphabetSize.fs
View File

@ -7,23 +7,23 @@ open BrotliLib.Numbers
module Behavior =
[<Theory>]
[<InlineData(0, 0uy)>]
[<InlineData(1, 0uy)>]
[<InlineData(2, 1uy)>]
[<InlineData(3, 2uy)>]
[<InlineData(4, 2uy)>]
[<InlineData(5, 3uy)>]
[<InlineData(6, 3uy)>]
[<InlineData(7, 3uy)>]
[<InlineData(8, 3uy)>]
[<InlineData(9, 4uy)>]
[<InlineData(16, 4uy)>]
[<InlineData(17, 5uy)>]
[<InlineData(32, 5uy)>]
[<InlineData(33, 6uy)>]
[<InlineData(256, 8uy)>]
[<InlineData(704, 10uy)>]
let ``alphabet of specified size calculates amount of bits per symbol correctly`` (symbols: int, bits: byte) =
[<InlineData(0, 0)>]
[<InlineData(1, 0)>]
[<InlineData(2, 1)>]
[<InlineData(3, 2)>]
[<InlineData(4, 2)>]
[<InlineData(5, 3)>]
[<InlineData(6, 3)>]
[<InlineData(7, 3)>]
[<InlineData(8, 3)>]
[<InlineData(9, 4)>]
[<InlineData(16, 4)>]
[<InlineData(17, 5)>]
[<InlineData(32, 5)>]
[<InlineData(33, 6)>]
[<InlineData(256, 8)>]
[<InlineData(704, 10)>]
let ``alphabet of specified size calculates amount of bits per symbol correctly`` (symbols: int, bits: int) =
Assert.Equal(bits, AlphabetSize(symbols).BitsPerSymbol)
[<Fact>]