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/* ====================================================================
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;
import java.io.ByteArrayInputStream;
/**
* Adapts a plain byte array to {@link LittleEndianInput}
*/
public class LittleEndianByteArrayInputStream extends ByteArrayInputStream implements LittleEndianInput {
/**
* Creates <code>LittleEndianByteArrayInputStream</code>
* that uses <code>buf</code> as its
* buffer array. The initial value of <code>pos</code>
* is <code>offset</code> and the initial value
* of <code>count</code> is the minimum of <code>offset+length</code>
* and <code>buf.length</code>.
* The buffer array is not copied. The buffer's mark is
* set to the specified offset.
*
* @param buf the input buffer.
* @param offset the offset in the buffer of the first byte to read.
* @param length the maximum number of bytes to read from the buffer.
*/
public LittleEndianByteArrayInputStream(byte[] buf, int offset, int length) { // NOSONAR
super(buf, offset, length);
}
/**
* Creates <code>LittleEndianByteArrayInputStream</code>
* that uses <code>buf</code> as its
* buffer array. The initial value of <code>pos</code>
* is <code>offset</code> and the initial value
* of <code>count</code> is the minimum of <code>offset+buf.length</code>
* and <code>buf.length</code>.
* The buffer array is not copied. The buffer's mark is
* set to the specified offset.
*
* @param buf the input buffer.
* @param offset the offset in the buffer of the first byte to read.
*/
public LittleEndianByteArrayInputStream(byte[] buf, int offset) {
this(buf, offset, buf.length - offset);
}
/**
* Creates a <code>LittleEndianByteArrayInputStream</code>
* so that it uses <code>buf</code> as its
* buffer array.
* The buffer array is not copied.
* The initial value of <code>pos</code>
* is <code>0</code> and the initial value
* of <code>count</code> is the length of
* <code>buf</code>.
*
* @param buf the input buffer.
*/
public LittleEndianByteArrayInputStream(byte[] buf) {
super(buf);
}
protected void checkPosition(int i) {
if (i > count - pos) {
throw new RuntimeException("Buffer overrun, having " + count + " bytes in the stream and position is at " + pos +
", but trying to increment position by " + i);
}
}
public int getReadIndex() {
return pos;
}
public void setReadIndex(int pos) {
if (pos < 0 || pos >= count) {
throw new IndexOutOfBoundsException();
}
this.pos = pos;
}
@Override
public byte readByte() {
checkPosition(1);
return (byte)read();
}
@Override
public int readInt() {
final int size = LittleEndianConsts.INT_SIZE;
checkPosition(size);
int le = LittleEndian.getInt(buf, pos);
long skipped = super.skip(size);
assert skipped == size : "Buffer overrun";
return le;
}
@Override
public long readLong() {
final int size = LittleEndianConsts.LONG_SIZE;
checkPosition(size);
long le = LittleEndian.getLong(buf, pos);
long skipped = super.skip(size);
assert skipped == size : "Buffer overrun";
return le;
}
@Override
public short readShort() {
final int size = LittleEndianConsts.SHORT_SIZE;
checkPosition(size);
short le = LittleEndian.getShort(buf, pos);
long skipped = super.skip(size);
assert skipped == size : "Buffer overrun";
return le;
}
@Override
public int readUByte() {
return readByte() & 0x00FF;
}
@Override
public int readUShort() {
return readShort() & 0x00FFFF;
}
public long readUInt() {
return readInt() & 0x00FFFFFFFFL;
}
@Override
public double readDouble() {
return Double.longBitsToDouble(readLong());
}
@Override
public void readFully(byte[] buffer, int off, int len) {
checkPosition(len);
read(buffer, off, len);
}
@Override
public void readFully(byte[] buffer) {
checkPosition(buffer.length);
read(buffer, 0, buffer.length);
}
@Override
public void readPlain(byte[] buf, int off, int len) {
readFully(buf, off, len);
}
}
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