src/pixy/io/ReadStrategyII.java

/*
 * Copyright (c) 2014-2021 by Wen Yu
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the Eclipse
 * Public License, v. 2.0 are satisfied: GNU General Public License, version 2
 * or any later version.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
 */

package pixy.io;

import java.io.InputStream;
import java.io.IOException;

/**
 * Read strategy for Intel byte order LITTLE-ENDIAN stream.
 * 
 * @author Wen Yu, yuwen_66@yahoo.com
 * @version 1.0 12/27/2012
 */
public class ReadStrategyII implements ReadStrategy {

	 private static final ReadStrategyII instance = new ReadStrategyII();
	 
	 public static ReadStrategyII getInstance() 
	 {
		 return instance;
	 }
	 
	 private ReadStrategyII(){}
	 
	 public int readInt(byte[] buf, int start_idx)
	 { 
		 return ((buf[start_idx++]&0xff)|((buf[start_idx++]&0xff)<<8)|
			               ((buf[start_idx++]&0xff)<<16)|((buf[start_idx++]&0xff)<<24));
	 }
	 
	 public int readInt(InputStream is) throws IOException
	 {
		 byte[] buf = new byte[4];
		 IOUtils.readFully(is, buf);
		 
		 return (((buf[3]&0xff)<<24)|((buf[2]&0xff)<<16)|((buf[1]&0xff)<<8)|(buf[0]&0xff));
	 }
	 
	 public long readLong(byte[] buf, int start_idx) 
     {    	 
         return ((buf[start_idx++]&0xffL)|(((buf[start_idx++]&0xffL)<<8)|((buf[start_idx++]&0xffL)<<16)|
        		 ((buf[start_idx++]&0xffL)<<24)|((buf[start_idx++]&0xffL)<<32)|((buf[start_idx++]&0xffL)<<40)|
        		   ((buf[start_idx++]&0xffL)<<48)|(buf[start_idx]&0xffL)<<56));
     }

	 public long readLong(InputStream is) throws IOException 
     {
    	 byte[] buf = new byte[8];
		 IOUtils.readFully(is, buf);
		 
         return (((buf[7]&0xffL)<<56)|((buf[6]&0xffL)<<48)|
                                ((buf[5]&0xffL)<<40)|((buf[4]&0xffL)<<32)|((buf[3]&0xffL)<<24)|
                                  ((buf[2]&0xffL)<<16)|((buf[1]&0xffL)<<8)|(buf[0]&0xffL));
     }
	 
	 public float readS15Fixed16Number(byte[] buf, int start_idx)
	 { 
		 short s15 = (short)((buf[start_idx++]&0xff)|((buf[start_idx++]&0xff)<<8));
		 int fixed16 = ((buf[start_idx++]&0xff)|((buf[start_idx]&0xff)<<8));
		 
		 return s15 + fixed16/65536.0f;
	 }

	 public float readS15Fixed16Number(InputStream is) throws IOException
	 { 		
		 byte[] buf = new byte[4];
		 IOUtils.readFully(is, buf);
		 
		 short s15 = (short)((buf[0]&0xff)|((buf[1]&0xff)<<8));
		 int fixed16 = ((buf[2]&0xff)|((buf[3]&0xff)<<8));
		 
		 return s15 + fixed16/65536.0f;	
	 }
	 
	 public short readShort(byte[] buf, int start_idx)
	 { 
		 return (short)((buf[start_idx++]&0xff)|((buf[start_idx]&0xff)<<8));
	 }

	 public short readShort(InputStream is) throws IOException
	 { 
		 byte[] buf = new byte[2];
		 IOUtils.readFully(is, buf);
		
		 return (short)(((buf[1]&0xff)<<8)|(buf[0]&0xff));
	 }
	 
	 public float readU16Fixed16Number(byte[] buf, int start_idx)
	 { 
		 int u16 = ((buf[start_idx++]&0xff)|((buf[start_idx++]&0xff)<<8));
		 int fixed16 = ((buf[start_idx++]&0xff)|((buf[start_idx]&0xff)<<8));
		 
		 return u16 + fixed16/65536.0f;
	 }

	 public float readU16Fixed16Number(InputStream is) throws IOException
	 { 
		 byte[] buf = new byte[4];
		 IOUtils.readFully(is, buf);
		 
		 int u16 = ((buf[0]&0xff)|((buf[1]&0xff)<<8));
		 int fixed16 = ((buf[2]&0xff)|((buf[3]&0xff)<<8));
		 
		 return u16 + fixed16/65536.0f;	
	 }

	 public float readU8Fixed8Number(byte[] buf, int start_idx)
	 { 
		 int u8 = (buf[start_idx++]&0xff);
		 int fixed8 = (buf[start_idx]&0xff);
		 
		 return u8 + fixed8/256.0f;
	 }

	 public float readU8Fixed8Number(InputStream is) throws IOException
	 { 
		 byte[] buf = new byte[2];
		 IOUtils.readFully(is, buf);
		 
		 int u8 = (buf[0]&0xff);
		 int fixed8 = (buf[1]&0xff);
		 
		 return u8 + fixed8/256.0f;	
	 }

	 public long readUnsignedInt(byte[] buf, int start_idx)
	 { 
		 return ((buf[start_idx++]&0xff)|((buf[start_idx++]&0xff)<<8)|
			         ((buf[start_idx++]&0xff)<<16)|((buf[start_idx++]&0xff)<<24))& 0xffffffffL;
	 }

	 public long readUnsignedInt(InputStream is) throws IOException
	 {
		 byte[] buf = new byte[4];
		 IOUtils.readFully(is, buf);
		 
		 return (((buf[3]&0xff)<<24)|((buf[2]&0xff)<<16)|
			                ((buf[1]&0xff)<<8)|(buf[0]&0xff))& 0xffffffffL;
	 }
	 
	 public int readUnsignedShort(byte[] buf, int start_idx)
	 { 
		 return ((buf[start_idx++]&0xff)|((buf[start_idx]&0xff)<<8));
	 }
	 
	 public int readUnsignedShort(InputStream is) throws IOException
	 { 
		 byte[] buf = new byte[2];
		 IOUtils.readFully(is, buf);
		
		 return (((buf[1]&0xff)<<8)|(buf[0]&0xff));
	 }    	 
}