WSeekableFile.java

/*
  * This file is part of WhereYouGo.
  *
  * WhereYouGo is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
  *
  * WhereYouGo is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with WhereYouGo.  If not, see <http://www.gnu.org/licenses/>.
  *
  * Copyright (C) 2012 Menion <whereyougo@asamm.cz>
  */ 

package menion.android.whereyougo;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;

import menion.android.whereyougo.utils.Logger;
import cz.matejcik.openwig.platform.SeekableFile;

public class WSeekableFile implements SeekableFile{

	private static final String TAG = "WSeekableFile";
	
	private RandomAccessFile raf;
	
	public WSeekableFile(File file) {
		try {
			this.raf = new RandomAccessFile(file, "rw");
		} catch (Exception e) {
			Logger.e(TAG, "WSeekableFile(" + file.getAbsolutePath() + ")", e);
		}
	}
	
	public long position() throws IOException {
//Logger.i(TAG, "position(), res:" + raf.getFilePointer());
		return raf.getFilePointer();
	}

	public int read() throws IOException {
		return raf.read();
	}

	public double readDouble() throws IOException {
    	try {
    		byte[] data = new byte[8];
    		raf.read(data);
    		return readDouble(data, 0, 8);
    	} catch (Exception e) {
    		return 0.0;
    	}
	}

	public void readFully(byte[] buf) throws IOException {
		raf.read(buf);
	}

	public int readInt() throws IOException {
		try {
			byte[] data = new byte[4];
			raf.read(data);
			return readInt(data, 0, 4);
		} catch (Exception e) {
			return 0;
		}
	}

	public long readLong() throws IOException {
		byte[] buffer = new byte[8];
		raf.read(buffer);
        return readLong(buffer, 0, 8);
	}

	public short readShort() throws IOException {
       	byte[] r = new byte[2];
       	raf.read(r);
       	return (short) ((r[1] << 8) | (r[0] & 0xff));
	}

	public String readString() throws IOException {
        StringBuffer sb = new StringBuffer();
        int b = raf.read();
        while (b > 0) {
            sb.append((char) b);
            b = raf.read();
        }
        return sb.toString();
	}

	public void seek(long pos) throws IOException {
//Logger.i(TAG, "seek(" + pos + ")");
		raf.seek(pos);
	}

	public long skip(long what) throws IOException {
//Logger.i(TAG, "skip(" + what + ")");
		return raf.skipBytes((int) what);
	}
	
	
	
    private static double readDouble(byte[] buffer, int start, int len) {
        long result = 0;
        for (int i = 0; i < len; i++) {
            result |= ((long) (buffer[start + i] & 0xff)) << (i * 8);
        }
        return Double.longBitsToDouble(result);
    }
    
    private static int readInt(byte[] buffer, int start, int len) {
        int result = 0;
        for (int i = 0; i < len; i++) {
            result += (buffer[start + i] & 0xFF) << (i * 8);
        }

        return result;
    }
    
    private static long readLong(byte[] buffer, int start, int len) {
    	long result = 0;
    	for (int i = 0; i < len; i++) {
    		result |= ((long) (buffer[start + i] & 0xff)) << (i * 8);
    	}
    	return result;
    }

}