EightBitNet/EightBit/Rom.cs

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3.1 KiB
C#
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// <copyright file="Rom.cs" company="Adrian Conlon">
// Copyright (c) Adrian Conlon. All rights reserved.
// </copyright>
namespace EightBit
{
using System;
using System.IO;
public class Rom : Memory
{
private byte[] bytes;
public Rom(int size) => this.bytes = new byte[size];
public Rom()
: this(0)
{
}
public override int Size => this.bytes.Length;
public static int Load(Stream file, ref byte[] output, int writeOffset = 0, int readOffset = 0, int limit = -1, int maximumSize = -1)
{
var size = (int)file.Length;
if ((maximumSize > 0) && ((size - readOffset) > maximumSize))
{
throw new InvalidOperationException("File is too large");
}
if ((limit < 0) || (limit > size))
{
limit = (int)size;
}
var extent = limit + writeOffset;
if (output.Length < extent)
{
var updated = new byte[extent];
Array.Copy(output, updated, output.Length);
output = updated;
}
file.Seek(readOffset, SeekOrigin.Begin);
using (var reader = new BinaryReader(file))
{
reader.Read(output, writeOffset, extent);
}
return size;
}
public static int Load(string path, ref byte[] output, int writeOffset = 0, int readOffset = 0, int limit = -1, int maximumSize = -1)
{
using (var file = File.Open(path, FileMode.Open))
{
return Load(file, ref output, writeOffset, readOffset, limit, maximumSize);
}
}
public override int Load(FileStream file, int writeOffset = 0, int readOffset = 0, int limit = -1)
{
var maximumSize = this.Size - writeOffset;
return Load(file, ref this.Bytes(), writeOffset, readOffset, limit, maximumSize);
}
public override int Load(string path, int writeOffset = 0, int readOffset = 0, int limit = -1)
{
var maximumSize = this.Size - writeOffset;
return Load(path, ref this.Bytes(), writeOffset, readOffset, limit, maximumSize);
}
public override int Load(byte[] from, int writeOffset = 0, int readOffset = 0, int limit = -1)
{
if (limit < 0)
{
limit = Math.Min(from.Length, this.Size - readOffset);
}
var extent = limit + writeOffset;
if (this.Size < extent)
{
var updated = new byte[extent];
Array.Copy(this.Bytes(), updated, this.Size);
this.Bytes() = updated;
}
Array.Copy(from, readOffset, this.Bytes(), writeOffset, limit);
return limit;
}
public override byte Peek(ushort address) => this.Bytes()[address];
protected ref byte[] Bytes() => ref this.bytes;
protected override void Poke(ushort address, byte value) => this.Bytes()[address] = value;
}
}