se.l4.commons.serialization.format.BinaryInput Maven / Gradle / Ivy

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package se.l4.commons.serialization.format;

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

/**
 * Input for binary format.
 * 
 * @author Andreas Holstenson
 *
 */
public class BinaryInput
	extends AbstractStreamingInput
{
	private static final int CHARS_SIZE = 1024;
	private static final ThreadLocal CHARS = new ThreadLocal()
	{
		@Override
		protected char[] initialValue()
		{
			return new char[1024];
		}
	};
	
	private final InputStream in;
	
	private final byte[] buffer;
	
	private int peekedByte;
	
	public BinaryInput(InputStream in)
	{
		this.in = in;
		buffer = new byte[8];
		
		peekedByte = -2;
	}
	
	@Override
	public void close()
		throws IOException
	{
		in.close();
	}

	@Override
	public Token peek()
		throws IOException
	{
		if(peekedByte == -2)
		{
			peekedByte = in.read();
		}
		
		switch(peekedByte)
		{
			case -1:
				return null;
			case BinaryOutput.TAG_KEY:
				return Token.KEY;
			case BinaryOutput.TAG_OBJECT_START:
				return Token.OBJECT_START;
			case BinaryOutput.TAG_OBJECT_END:
				return Token.OBJECT_END;
			case BinaryOutput.TAG_LIST_START:
				return Token.LIST_START;
			case BinaryOutput.TAG_LIST_END:
				return Token.LIST_END;
			case BinaryOutput.TAG_NULL:
				return Token.NULL;
			default:
				return Token.VALUE;
		}
	}

	@Override
	protected Token next0()
		throws IOException
	{
		Token current = peek();
		if(current == Token.KEY || current == Token.VALUE || current == Token.NULL)
		{
			// Read actual data of keys and values
			readValue();
		}
		
		peekedByte = in.read();
		
		return current;
	}
	
	private void readBuffer(int len)
		throws IOException
	{
		int n = 0;
		while(n < len)
		{
			int count = in.read(buffer, n, len - n);
			if(count < 0)
			{
				throw new EOFException("Expected to read " + len + " bytes, but could only read " + n);
			}
			n += count;
		}
	}
	
	private double readDouble()
		throws IOException
	{
		readBuffer(8);
		long value = ((long) buffer[0] & 0xff) |
			((long) buffer[1] & 0xff) << 8 |
			((long) buffer[2] & 0xff) << 16 |
			((long) buffer[3] & 0xff) << 24 |
			((long) buffer[4] & 0xff) << 32 |
			((long) buffer[5] & 0xff) << 40 |
			((long) buffer[6] & 0xff) << 48 |
			((long) buffer[7] & 0xff) << 56;
		
		return Double.longBitsToDouble(value);
	}
	
	private float readFloat()
		throws IOException
	{
		readBuffer(4);
		int value = (buffer[0] & 0xff) |
			(buffer[1] & 0xff) << 8 |
			(buffer[2] & 0xff) << 16 |
			(buffer[3] & 0xff) << 24;
		
		return Float.intBitsToFloat(value);
	}
	
	private int readInteger()
		throws IOException
	{
		int shift = 0;
		int result = 0;
		while(shift < 32)
		{
			final byte b = (byte) in.read();
			result |= (b & 0x7F) << shift;
			if((b & 0x80) == 0) return result;
			
			shift += 7;
		}
		
		throw new EOFException("Invalid integer");
	}
	
	private long readLong()
		throws IOException
	{
		int shift = 0;
		long result = 0;
		while(shift < 64)
		{
			final byte b = (byte) in.read();
			result |= (long) (b & 0x7F) << shift;
			if((b & 0x80) == 0) return result;
			
			shift += 7;
		}
		
		throw new EOFException("Invalid long");
	}
	
	private String readString()
		throws IOException
	{
		int length = readInteger();
		char[] chars = length < CHARS_SIZE ? CHARS.get() : new char[length];
		
		for(int i=0; i> 4;
			if(t > -1 && t < 8)
			{
				chars[i] = (char) c;
			}
			else if(t == 12 || t == 13)
			{
				chars[i] = (char) ((c & 0x1f) << 6 | in.read() & 0x3f);
			}
			else if(t == 14)
			{
				chars[i] = (char) ((c & 0x0f) << 12 
					| (in.read() & 0x3f) << 6
					| (in.read() & 0x3f) << 0);
			}
		}
		
		return new String(chars, 0, length);
	}

	private byte[] readByteArray()
		throws IOException
	{
		int length = readInteger();
		byte[] buffer = new byte[length];
		int read = in.read(buffer);
		
		if(read != length)
		{
			throw new EOFException("Stream ended before entire byte array was sent");
		}
		
		return buffer;
	}
	
	private void readValue()
		throws IOException
	{
		switch(peekedByte)
		{
			case BinaryOutput.TAG_BOOLEAN:
				int b = in.read();
				setValue(b == 1);
				break;
			case BinaryOutput.TAG_DOUBLE:
				setValue(readDouble());
				break;
			case BinaryOutput.TAG_FLOAT:
				setValue(readFloat());
				break;
			case BinaryOutput.TAG_INT:
				int i = readInteger();
				i = (i >>> 1) ^ -(i & 1);
				setValue(i);
				break;
			case BinaryOutput.TAG_POSITIVE_INT:
				setValue(readInteger());
				break;
			case BinaryOutput.TAG_NEGATIVE_INT:
				setValue(-readInteger());
				break;
			case BinaryOutput.TAG_LONG:
				long l = readLong();
				l = (l >>> 1) ^ -(l & 1);
				setValue(l);
				break;
			case BinaryOutput.TAG_POSITIVE_LONG:
				setValue(readLong());
				break;
			case BinaryOutput.TAG_NEGATIVE_LONG:
				setValue(-readLong());
				break;
			case BinaryOutput.TAG_NULL:
				setValue(null);
				break;
			case BinaryOutput.TAG_KEY:
			case BinaryOutput.TAG_STRING:
				setValue(readString());
				break;
			case BinaryOutput.TAG_BYTE_ARRAY:
				setValue(readByteArray());
				break;
			default:
				throw new IOException("Unexpected value type, no idea what to do (type was " + peekedByte + ")");
		}
		
	}
}