SabreTools/SabreTools.Compression
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Make Blast like others

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This commit is contained in:
Matt Nadareski
2024-12-11 09:20:14 -05:00
parent b2fe81dac8
commit 97a83b42ee
2 changed files with 58 additions and 38 deletions
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67
SabreTools.Compression/Blast/BlastDecoder.cs → SabreTools.Compression/Blast/Decompressor.cs
View File

@@ -30,29 +30,40 @@
*/
using System;
using System.Collections.Generic;
using System.IO;
using static SabreTools.Compression.Blast.Constants;
namespace SabreTools.Compression.Blast
{
public unsafe static class BlastDecoder
/// <summary>
/// blast() decompresses the PKWare Data Compression Library (DCL) compressed
/// format. It provides the same functionality as the explode() function in
/// that library. (Note: PKWare overused the "implode" verb, and the format
/// used by their library implode() function is completely different and
/// incompatible with the implode compression method supported by PKZIP.)
///
/// The binary mode for stdio functions should be used to assure that the
/// compressed data is not corrupted when read or written. For example:
/// fopen(..., "rb") and fopen(..., "wb").
/// </summary>
public unsafe class Decompressor
{
#region Huffman Encoding
/// <summary>
/// Literal code
/// </summary>
private static readonly Huffman litcode = new(MAXBITS + 1, 256);
private readonly Huffman litcode = new(MAXBITS + 1, 256);
/// <summary>
/// Length code
/// </summary>
private static readonly Huffman lencode = new(MAXBITS + 1, 16);
private readonly Huffman lencode = new(MAXBITS + 1, 16);
/// <summary>
/// Distance code
/// </summary>
private static readonly Huffman distcode = new(MAXBITS + 1, 64);
private readonly Huffman distcode = new(MAXBITS + 1, 64);
/// <summary>
/// Base for length codes
@@ -72,10 +83,12 @@ namespace SabreTools.Compression.Blast
#endregion
#region Constructors
/// <summary>
/// Static constructor
/// Create a Blast decompressor
/// </summary>
static BlastDecoder()
private Decompressor()
{
// Repeated code lengths of literal codes
byte[] litlen =
@@ -105,20 +118,29 @@ namespace SabreTools.Compression.Blast
}
/// <summary>
/// blast() decompresses the PKWare Data Compression Library (DCL) compressed
/// format. It provides the same functionality as the explode() function in
/// that library. (Note: PKWare overused the "implode" verb, and the format
/// used by their library implode() function is completely different and
/// incompatible with the implode compression method supported by PKZIP.)
///
/// The binary mode for stdio functions should be used to assure that the
/// compressed data is not corrupted when read or written. For example:
/// fopen(..., "rb") and fopen(..., "wb").
/// Create a Blast decompressor
/// </summary>
public static int Blast(byte[] inhow, List<byte> outhow)
public static Decompressor Create() => new();
#endregion
/// <summary>
/// Decompress source data to an output stream
/// </summary>
public bool CopyTo(byte[] source, Stream dest)
=> CopyTo(new MemoryStream(source), dest);
/// <summary>
/// Decompress source data to an output stream
/// </summary>
public bool CopyTo(Stream source, Stream dest)
{
// Ignore unwritable streams
if (!dest.CanWrite)
return false;
// Input/output state
var state = new State(inhow, outhow);
var state = new State(source, dest);
// Attempt to decompress using the above state
int err;
@@ -136,7 +158,7 @@ namespace SabreTools.Compression.Blast
if (err != 1 && state.Next != 0 && !state.ProcessOutput() && err == 0)
err = 1;
return err;
return err == 0;
}
/// <summary>
@@ -176,7 +198,7 @@ namespace SabreTools.Compression.Blast
/// ignoring whether the length is greater than the distance or not implements
/// this correctly.
/// </remarks>
private static int Decomp(State state)
private int Decomp(State state)
{
int symbol; // decoded symbol, extra bits for distance
int len; // length for copy
@@ -194,7 +216,7 @@ namespace SabreTools.Compression.Blast
return -2;
// Decode literals and length/distance pairs
do
while (true)
{
if (state.Bits(1) != 0)
{
@@ -256,13 +278,12 @@ namespace SabreTools.Compression.Blast
{
if (!state.ProcessOutput())
return 1;
state.Next = 0;
state.First = false;
}
}
}
while (true);
return 0;
}

29
SabreTools.Compression/Blast/State.cs
View File

@@ -1,5 +1,5 @@
using System;
using System.Collections.Generic;
using System.IO;
using static SabreTools.Compression.Blast.Constants;
namespace SabreTools.Compression.Blast
@@ -14,12 +14,12 @@ namespace SabreTools.Compression.Blast
/// <summary>
/// Opaque information passed to InputFunction()
/// </summary>
public byte[] InHow { get; set; }
public Stream Source { get; set; }
/// <summary>
/// Next input location
/// </summary>
public List<byte> Input { get; set; }
public byte[] Input { get; set; }
/// <summary>
/// Pointer to the next input location
@@ -48,7 +48,7 @@ namespace SabreTools.Compression.Blast
/// <summary>
/// Opaque information passed to OutputFunction()
/// </summary>
public List<byte> OutHow { get; set; }
public Stream Dest { get; set; }
/// <summary>
/// Index of next write location in out[]
@@ -63,7 +63,7 @@ namespace SabreTools.Compression.Blast
/// <summary>
/// Output buffer and sliding window
/// </summary>
public byte[] Output { get; set; } = new byte[MAXWIN];
public readonly byte[] Output = new byte[MAXWIN];
/// <summary>
/// Pointer to the next output location
@@ -75,18 +75,16 @@ namespace SabreTools.Compression.Blast
/// <summary>
/// Constructor
/// </summary>
/// <param name="inhow">Input byte array</param>
/// <param name="outhow">Output byte list</param>
public State(byte[] inhow, List<byte> outhow)
public State(Stream source, Stream dest)
{
InHow = inhow;
Input = new List<byte>();
Source = source;
Input = [];
InputPtr = 0;
Left = 0;
BitBuf = 0;
BitCnt = 0;
OutHow = outhow;
Dest = dest;
Next = 0;
First = true;
}
@@ -116,7 +114,7 @@ namespace SabreTools.Compression.Blast
}
// Load eight bits
val |= (int)(Input[InputPtr++]) << BitCnt;
val |= Input[InputPtr++] << BitCnt;
Left--;
BitCnt += 8;
}
@@ -135,8 +133,8 @@ namespace SabreTools.Compression.Blast
/// <returns>Amount of data in Input</returns>
public uint ProcessInput()
{
Input = [.. InHow];
return (uint)Input.Count;
int read = Source.Read(Input, 0, 4096);
return (uint)read;
}
/// <summary>
@@ -149,7 +147,8 @@ namespace SabreTools.Compression.Blast
{
byte[] next = new byte[Next];
Array.Copy(Output, next, next.Length);
OutHow.AddRange(next);
Dest.Write(next);
Dest.Flush();
return true;
}
catch