| /* ==================================================================== |
| 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.poi.util; |
| |
| /** |
| * Adapts a plain byte array to {@link LittleEndianInput} |
| * |
| * @author Josh Micich |
| */ |
| public final class LittleEndianByteArrayInputStream implements LittleEndianInput { |
| private final byte[] _buf; |
| private final int _endIndex; |
| private int _readIndex; |
| |
| public LittleEndianByteArrayInputStream(byte[] buf, int startOffset, int maxReadLen) { |
| _buf = buf; |
| _readIndex = startOffset; |
| _endIndex = startOffset + maxReadLen; |
| } |
| public LittleEndianByteArrayInputStream(byte[] buf, int startOffset) { |
| this(buf, startOffset, buf.length - startOffset); |
| } |
| public LittleEndianByteArrayInputStream(byte[] buf) { |
| this(buf, 0, buf.length); |
| } |
| |
| public int available() { |
| return _endIndex - _readIndex; |
| } |
| private void checkPosition(int i) { |
| if (i > _endIndex - _readIndex) { |
| throw new RuntimeException("Buffer overrun"); |
| } |
| } |
| |
| public int getReadIndex() { |
| return _readIndex; |
| } |
| public byte readByte() { |
| checkPosition(1); |
| return _buf[_readIndex++]; |
| } |
| |
| public int readInt() { |
| checkPosition(4); |
| int i = _readIndex; |
| |
| int b0 = _buf[i++] & 0xFF; |
| int b1 = _buf[i++] & 0xFF; |
| int b2 = _buf[i++] & 0xFF; |
| int b3 = _buf[i++] & 0xFF; |
| _readIndex = i; |
| return (b3 << 24) + (b2 << 16) + (b1 << 8) + (b0 << 0); |
| } |
| public long readLong() { |
| checkPosition(8); |
| int i = _readIndex; |
| |
| int b0 = _buf[i++] & 0xFF; |
| int b1 = _buf[i++] & 0xFF; |
| int b2 = _buf[i++] & 0xFF; |
| int b3 = _buf[i++] & 0xFF; |
| int b4 = _buf[i++] & 0xFF; |
| int b5 = _buf[i++] & 0xFF; |
| int b6 = _buf[i++] & 0xFF; |
| int b7 = _buf[i++] & 0xFF; |
| _readIndex = i; |
| return (((long)b7 << 56) + |
| ((long)b6 << 48) + |
| ((long)b5 << 40) + |
| ((long)b4 << 32) + |
| ((long)b3 << 24) + |
| (b2 << 16) + |
| (b1 << 8) + |
| (b0 << 0)); |
| } |
| public short readShort() { |
| return (short)readUShort(); |
| } |
| public int readUByte() { |
| checkPosition(1); |
| return _buf[_readIndex++] & 0xFF; |
| } |
| public int readUShort() { |
| checkPosition(2); |
| int i = _readIndex; |
| |
| int b0 = _buf[i++] & 0xFF; |
| int b1 = _buf[i++] & 0xFF; |
| _readIndex = i; |
| return (b1 << 8) + (b0 << 0); |
| } |
| public void readFully(byte[] buf, int off, int len) { |
| checkPosition(len); |
| System.arraycopy(_buf, _readIndex, buf, off, len); |
| _readIndex+=len; |
| } |
| public void readFully(byte[] buf) { |
| readFully(buf, 0, buf.length); |
| } |
| public double readDouble() { |
| return Double.longBitsToDouble(readLong()); |
| } |
| } |