SabreTools/SabreTools.Compression
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Start adding Quantum decompression

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This commit is contained in:
Matt Nadareski
2023-09-23 00:13:08 -04:00
parent 8e5cf3ee2e
commit d75883a6cf
1 changed files with 76 additions and 0 deletions
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76
Quantum/Decompressor.cs
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@@ -1,6 +1,8 @@
using System;
using System.Collections.Generic;
using System.IO;
using SabreTools.Models.Compression.Quantum;
using static SabreTools.Models.Compression.Quantum.Constants;
namespace SabreTools.Compression.Quantum
{
@@ -177,6 +179,80 @@ namespace SabreTools.Compression.Quantum
/// <returns>Byte array representing the decompressed data, null on error</returns>
public byte[] Process()
{
// Initialize the coding state
CS_H = 0xffff;
CS_L = 0x0000;
CS_C = (ushort)(_bitStream.ReadBitsMSB(16) ?? 0);
// Loop until the end of the stream
var bytes = new List<byte>();
while (true)
{
// Determine the selector to use
int selector = GetSymbol(_selector);
// Handle literal selectors
if (selector < 4)
{
switch (selector)
{
case 0:
bytes.Add((byte)GetSymbol(_model0));
break;
case 1:
bytes.Add((byte)GetSymbol(_model1));
break;
case 2:
bytes.Add((byte)GetSymbol(_model2));
break;
case 3:
bytes.Add((byte)GetSymbol(_model3));
break;
default:
throw new ArgumentOutOfRangeException();
}
}
// Handle LZ selectors
else
{
int offset, length;
switch (selector)
{
case 4:
int model4sym = GetSymbol(_model4);
int model4extra = _bitStream.ReadBitsMSB(PositionExtraBits[model4sym]);
offset = PositionSlot[model4sym] + model4extra + 1;
length = 3;
break;
case 5:
int model5sym = GetSymbol(_model5);
int model5extra = _bitStream.ReadBitsMSB(PositionExtraBits[model5sym]);
offset = PositionSlot[model5sym] + model5extra + 1;
length = 4;
break;
case 6:
int lengthSym = GetSymbol(_model6len);
int lengthExtra = _bitStream.ReadBitsMSB(LengthExtraBits[lengthSym]);
length = LengthSlot[lengthSym] + lengthExtra + 5;
int model6sym = GetSymbol(_model6);
int model6extra = _bitStream.ReadBitsMSB(PositionExtraBits[model6sym]);
offset = PositionSlot[model6sym] + model6extra + 1;
break;
default:
throw new ArgumentOutOfRangeException();
}
// TODO: Finish implementation:
// - Copy data from the offsets to the lengths
// - Return the decoded byte array
}
}
throw new NotImplementedException();
}