/* * 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; /** * This class contains some functionality to read a byte buffer. * * @author Villu Ruusmann * @version $Revision$ */ 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, "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 { return (byte) readUnsignedByte(); } /** * 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; } /** * 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 { byte[] bytes = new byte[length]; for (int i = 0; i < length; i++) { bytes[i] = readByte(); } return bytes; } private int read() { try { int value = inputBuffer[bufferPosition] & 0xff; bufferPosition++; return value; } catch (RuntimeException re) { return -1; } } }