GARbro-mirror/GameRes/ArcStream.cs
morkt 1f45de7d35 (ArcViewStream): restored bufferization.
apparently performance is improved compared to unbuffered mapped file
view reads.
2017-04-02 14:41:25 +04:00

445 lines
15 KiB
C#

//! \file ArcStream.cs
//! \date Thu Mar 30 03:19:41 2017
//! \brief Stream on top of the memory-mapped view.
//
// Copyright (C) 2014-2017 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using GameRes.Utility;
namespace GameRes
{
public class ArcViewStream : Stream, IBinaryStream
{
private readonly ArcView.Frame m_view;
private readonly long m_start;
private readonly long m_size;
private long m_position;
private byte[] m_buffer;
private int m_buffer_pos; // read position within buffer
private int m_buffer_len; // length of bytes read in buffer
private const int DefaultBufferSize = 0x1000;
public string Name { get; set; }
public uint Signature { get { return ReadSignature(); } }
public Stream AsStream { get { return this; } }
public override bool CanRead { get { return !disposed; } }
public override bool CanSeek { get { return !disposed; } }
public override bool CanWrite { get { return false; } }
public override long Length { get { return m_size; } }
public override long Position
{
get { return m_position + (m_buffer_pos - m_buffer_len); }
set {
if (value < 0)
throw new ArgumentOutOfRangeException ("value", "Stream position is out of range.");
var buffer_start = m_position - m_buffer_len;
if (m_buffer_pos != m_buffer_len && value >= buffer_start && value < m_position)
{
m_buffer_pos = (int)(value - buffer_start);
}
else
{
m_position = value;
m_buffer_pos = m_buffer_len = 0;
}
}
}
public ArcViewStream (ArcView file)
{
m_view = file.CreateFrame();
m_start = 0;
m_size = file.MaxOffset;
m_position = 0;
Name = file.Name;
}
public ArcViewStream (ArcView.Frame view, string name = null)
{
m_view = view;
m_start = m_view.Offset;
m_size = m_view.Reserved;
m_position = 0;
Name = name ?? "";
}
public ArcViewStream (ArcView file, long offset, uint size, string name = null)
: this (new ArcView.Frame (file, offset, size), name)
{
}
public ArcViewStream (ArcView.Frame view, long offset, uint size, string name = null)
{
m_view = view;
m_start = offset;
m_size = Math.Min (size, m_view.Reserve (offset, size));
m_position = 0;
Name = name ?? "";
}
/// <summary>
/// Read stream signature (first 4 bytes) without altering current read position.
/// </summary>
public uint ReadSignature ()
{
return m_view.ReadUInt32 (m_start);
}
byte[] m_header;
int m_header_size;
public CowArray<byte> ReadHeader (int size)
{
if (m_header_size < size)
{
if (null == m_header || m_header.Length < size)
Array.Resize (ref m_header, (size + 0xF) & ~0xF);
long position = m_start + m_header_size;
m_header_size += m_view.Read (position, m_header, m_header_size, (uint)(size - m_header_size));
}
if (size > m_header_size)
{
Position = m_header_size;
throw new EndOfStreamException();
}
Position = size;
return new CowArray<byte> (m_header, 0, size);
}
private void RefillBuffer ()
{
if (null == m_buffer)
m_buffer = new byte[DefaultBufferSize];
uint length = (uint)Math.Min (m_size - m_position, m_buffer.Length);
m_buffer_len = m_view.Read (m_start + m_position, m_buffer, 0, length);
m_position += m_buffer_len;
m_buffer_pos = 0;
}
private void FlushBuffer ()
{
if (m_buffer_len != 0)
{
m_position += m_buffer_pos - m_buffer_len;
m_buffer_pos = m_buffer_len = 0;
}
}
private void EnsureAvailable (int length)
{
if (m_buffer_pos + length > m_buffer_len)
{
FlushBuffer();
if (m_position + length > m_size)
throw new EndOfStreamException();
RefillBuffer();
}
}
private int ReadFromBuffer (byte[] array, int offset, int count)
{
int available = Math.Min (m_buffer_len - m_buffer_pos, count);
if (available > 0)
{
Buffer.BlockCopy (m_buffer, m_buffer_pos, array, offset, available);
m_buffer_pos += available;
}
return available;
}
public int PeekByte ()
{
if (m_buffer_pos == m_buffer_len)
RefillBuffer();
if (m_buffer_pos == m_buffer_len)
return -1;
return m_buffer[m_buffer_pos];
}
public override int ReadByte ()
{
int b = PeekByte();
if (-1 != b)
++m_buffer_pos;
return b;
}
public sbyte ReadInt8 ()
{
int b = ReadByte();
if (-1 == b)
throw new EndOfStreamException();
return (sbyte)b;
}
public byte ReadUInt8 ()
{
return (byte)ReadInt8();
}
public short ReadInt16 ()
{
EnsureAvailable (2);
var v = m_buffer.ToInt16 (m_buffer_pos);
m_buffer_pos += 2;
return v;
}
public ushort ReadUInt16 ()
{
return (ushort)ReadInt16();
}
public int ReadInt24 ()
{
EnsureAvailable (3);
int v = m_buffer.ToInt24 (m_buffer_pos);
m_buffer_pos += 3;
return v;
}
public int ReadInt32 ()
{
EnsureAvailable (4);
int v = m_buffer.ToInt32 (m_buffer_pos);
m_buffer_pos += 4;
return v;
}
public uint ReadUInt32 ()
{
return (uint)ReadInt32();
}
public long ReadInt64 ()
{
EnsureAvailable (8);
var v = m_buffer.ToInt64 (m_buffer_pos);
m_buffer_pos += 8;
return v;
}
public ulong ReadUInt64 ()
{
return (ulong)ReadInt64();
}
public string ReadCString (int length)
{
return ReadCString (length, Encodings.cp932);
}
public string ReadCString (int length, Encoding enc)
{
if (m_buffer_pos == m_buffer_len && length <= DefaultBufferSize)
RefillBuffer();
if (m_buffer_pos + length <= m_buffer_len)
{
// whole string fit into buffer
var str = Binary.GetCString (m_buffer, m_buffer_pos, length, enc);
m_buffer_pos += length;
return str;
}
else if (length > DefaultBufferSize)
{
// requested string length is larger than internal buffer size
var string_buffer = ReadBytes (length);
return Binary.GetCString (string_buffer, 0, string_buffer.Length, enc);
}
else
{
int available = m_buffer_len - m_buffer_pos;
if (available > 0 && m_buffer_pos != 0)
Buffer.BlockCopy (m_buffer, m_buffer_pos, m_buffer, 0, available);
int count = (int)Math.Min (m_buffer.Length - available, m_size - m_position);
if (count > 0)
{
int read = m_view.Read (m_start + m_position, m_buffer, available, (uint)count);
m_position += read;
available += read;
}
m_buffer_len = available;
m_buffer_pos = Math.Min (length, m_buffer_len);
return Binary.GetCString (m_buffer, 0, m_buffer_pos, enc);
}
}
public string ReadCString ()
{
return ReadCString (Encodings.cp932);
}
public string ReadCString (Encoding enc)
{
if (m_buffer_pos == m_buffer_len)
RefillBuffer();
int available = m_buffer_len - m_buffer_pos;
if (0 == available)
return string.Empty;
int zero = Array.IndexOf<byte> (m_buffer, 0, m_buffer_pos, available);
if (zero != -1)
{
// null byte found within buffer
var str = enc.GetString (m_buffer, m_buffer_pos, zero - m_buffer_pos);
m_buffer_pos = zero+1;
return str;
}
// underlying view includes whole stream
if (m_view.Offset <= m_start && m_view.Offset + m_view.Reserved >= m_start + m_size)
return ReadCStringUnsafe (enc, available);
var string_buf = new byte[Math.Max (0x20, available * 2)];
ReadFromBuffer (string_buf, 0, available);
int size = available;
for (;;)
{
int b = ReadByte();
if (-1 == b || 0 == b)
break;
if (string_buf.Length == size)
{
Array.Resize (ref string_buf, checked(size*3/2));
}
string_buf[size++] = (byte)b;
}
return enc.GetString (string_buf, 0, size);
}
private unsafe string ReadCStringUnsafe (Encoding enc, int skip_bytes = 0)
{
Debug.Assert (m_view.Offset + m_view.Reserved >= m_start + m_size);
FlushBuffer();
using (var ptr = m_view.GetPointer())
{
byte* s = ptr.Value + (m_start - m_view.Offset + m_position);
int view_length = (int)(m_size - m_position);
int string_length = Math.Min (skip_bytes, view_length);
while (string_length < view_length && 0 != s[string_length])
{
++string_length;
}
m_position += string_length;
if (string_length < view_length)
++m_position;
return new string ((sbyte*)s, 0, string_length, enc);
}
}
public byte[] ReadBytes (int count)
{
if (m_buffer_pos + count <= m_buffer_len && m_buffer_len != 0)
{
var data = new CowArray<byte> (m_buffer, m_buffer_pos, count).ToArray();
m_buffer_pos += count;
return data;
}
var current_pos = Position;
if (0 == count || current_pos >= m_size)
return new byte[0];
var bytes = m_view.ReadBytes (m_start+current_pos, (uint)Math.Min (count, m_size - current_pos));
Position = current_pos + bytes.Length;
return bytes;
}
#region System.IO.Stream methods
public override void Flush()
{
FlushBuffer();
}
public override long Seek (long offset, SeekOrigin origin)
{
switch (origin)
{
case SeekOrigin.Current: offset += Position; break;
case SeekOrigin.End: offset += m_size; break;
}
Position = offset;
return offset;
}
public override void SetLength (long length)
{
throw new NotSupportedException ("GameRes.ArcStream.SetLength method is not supported");
}
public override int Read (byte[] buffer, int offset, int count)
{
int read_from_buffer = ReadFromBuffer (buffer, offset, count);
offset += read_from_buffer;
count -= read_from_buffer;
if (0 == count || m_position >= m_size)
return read_from_buffer;
if (count < DefaultBufferSize)
{
RefillBuffer();
count = Math.Min (count, m_buffer_len);
Buffer.BlockCopy (m_buffer, m_buffer_pos, buffer, offset, count);
m_buffer_pos += count;
return read_from_buffer + count;
}
else
{
uint view_count = (uint)Math.Min (count, m_size - m_position);
int read_from_view = m_view.Read (m_start + m_position, buffer, offset, view_count);
m_position += read_from_view;
return read_from_buffer + read_from_view;
}
}
public override void Write (byte[] buffer, int offset, int count)
{
throw new NotSupportedException("GameRes.ArcStream.Write method is not supported");
}
public override void WriteByte (byte value)
{
throw new NotSupportedException("GameRes.ArcStream.WriteByte method is not supported");
}
#endregion
#region IDisposable Members
bool disposed = false;
protected override void Dispose (bool disposing)
{
if (!disposed)
{
if (disposing)
{
m_view.Dispose();
}
disposed = true;
base.Dispose (disposing);
}
}
#endregion
}
}