org.apache.fontbox.cff.DataInput Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.fontbox.cff;
import java.io.EOFException;
import java.io.IOException;
import org.apache.fontbox.util.Charsets;
/**
* This class contains some functionality to read a byte buffer.
*
* @author Villu Ruusmann
*/
public class DataInput
{
private byte[] inputBuffer = null;
private int bufferPosition = 0;
/**
* Constructor.
* @param buffer the buffer to be read
*/
public DataInput(byte[] buffer)
{
inputBuffer = buffer;
}
/**
* Determines if there are any bytes left to read or not.
* @return true if there are any bytes left to read
*/
public boolean hasRemaining()
{
return bufferPosition < inputBuffer.length;
}
/**
* Returns the current position.
* @return current position
*/
public int getPosition()
{
return bufferPosition;
}
/**
* Sets the current position to the given value.
* @param position the given position
*/
public void setPosition(int position)
{
bufferPosition = position;
}
/**
* Returns the buffer as an ISO-8859-1 string.
* @return the buffer as string
* @throws IOException if an error occurs during reading
*/
public String getString() throws IOException
{
return new String(inputBuffer, Charsets.ISO_8859_1);
}
/**
* Read one single byte from the buffer.
* @return the byte
* @throws IOException if an error occurs during reading
*/
public byte readByte() throws IOException
{
try
{
byte value = inputBuffer[bufferPosition];
bufferPosition++;
return value;
}
catch (RuntimeException re)
{
return -1;
}
}
/**
* Read one single unsigned byte from the buffer.
* @return the unsigned byte as int
* @throws IOException if an error occurs during reading
*/
public int readUnsignedByte() throws IOException
{
int b = read();
if (b < 0)
{
throw new EOFException();
}
return b;
}
/**
* Peeks one single unsigned byte from the buffer.
* @return the unsigned byte as int
* @throws IOException if an error occurs during reading
*/
public int peekUnsignedByte(int offset) throws IOException
{
int b = peek(offset);
if (b < 0)
{
throw new EOFException();
}
return b;
}
/**
* Read one single short value from the buffer.
* @return the short value
* @throws IOException if an error occurs during reading
*/
public short readShort() throws IOException
{
return (short) readUnsignedShort();
}
/**
* Read one single unsigned short (2 bytes) value from the buffer.
* @return the unsigned short value as int
* @throws IOException if an error occurs during reading
*/
public int readUnsignedShort() throws IOException
{
int b1 = read();
int b2 = read();
if ((b1 | b2) < 0)
{
throw new EOFException();
}
return b1 << 8 | b2;
}
/**
* Read one single int (4 bytes) from the buffer.
* @return the int value
* @throws IOException if an error occurs during reading
*/
public int readInt() throws IOException
{
int b1 = read();
int b2 = read();
int b3 = read();
int b4 = read();
if ((b1 | b2 | b3 | b4) < 0)
{
throw new EOFException();
}
return b1 << 24 | b2 << 16 | b3 << 8 | b4;
}
/**
* Read a number of single byte values from the buffer.
* @param length the number of bytes to be read
* @return an array with containing the bytes from the buffer
* @throws IOException if an error occurs during reading
*/
public byte[] readBytes(int length) throws IOException
{
if (inputBuffer.length - bufferPosition < length)
{
throw new EOFException();
}
byte[] bytes = new byte[length];
System.arraycopy(inputBuffer, bufferPosition, bytes, 0, length);
bufferPosition += length;
return bytes;
}
private int read()
{
try
{
int value = inputBuffer[bufferPosition] & 0xff;
bufferPosition++;
return value;
}
catch (RuntimeException re)
{
return -1;
}
}
private int peek(int offset)
{
try
{
return inputBuffer[bufferPosition + offset] & 0xff;
}
catch (RuntimeException re)
{
return -1;
}
}
public int length()
{
return inputBuffer.length;
}
}