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/*
* Copyright (c) 2010-2015 Pivotal Software, Inc. All rights reserved.
*
* Licensed 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. See accompanying
* LICENSE file.
*/
package com.gemstone.gemfire.internal;
import java.io.DataInput;
import java.io.EOFException;
import java.io.IOException;
import com.gemstone.gemfire.internal.shared.Version;
/**
* A reusable {@link DataInput} implementation that wraps a given byte array. It
* also implements {@link VersionedDataStream} for a stream coming from a
* different product version.
*
* @author swale
* @since 7.1
*/
public final class ByteArrayDataInput extends DataInputStreamBase implements
VersionedDataStream {
private byte[] bytes;
private int nBytes;
private Version version;
/**
* Create a {@link DataInput} whose contents are empty.
*/
public ByteArrayDataInput() {
}
/**
* Initialize this byte array stream with given byte array and version.
*
* @param bytes
* the content of this stream. Note that this byte array will be read
* by this class (a copy is not made) so it should not be changed
* externally.
* @param version
* the product version that serialized the object on given bytes
*/
public final void initialize(byte[] bytes, Version version) {
this.bytes = bytes;
this.nBytes = bytes.length;
this.pos = 0;
this.version = version;
}
/**
* Initialize this byte array stream with given byte array and version.
*
* @param bytes
* the content of this stream. Note that this byte array will be read
* by this class (a copy is not made) so it should not be changed
* externally.
* @param version
* the product version that serialized the object on given bytes
*/
public final void initialize(byte[] bytes, int offset, int len,
Version version) {
if (offset < 0 || len < 0 || bytes.length < (offset + len)) {
throw new IndexOutOfBoundsException();
}
this.bytes = bytes;
this.nBytes = offset + len;
this.pos = offset;
this.version = version;
}
public byte[] array() {
return this.bytes;
}
/**
* {@inheritDoc}
*/
@Override
public final Version getVersion() {
return this.version;
}
/**
* {@inheritDoc}
*/
@Override
public final int read() throws IOException {
if (this.pos < this.nBytes) {
return (this.bytes[this.pos++] & 0xff);
}
else {
return -1;
}
}
/**
* {@inheritDoc}
*/
@Override
public final int read(byte[] b, int off, int len) {
if (b == null) {
throw new NullPointerException();
}
else if (off < 0 || len < 0 || b.length < (off + len)) {
throw new IndexOutOfBoundsException();
}
final int capacity = (this.nBytes - this.pos);
if (len > capacity) {
if (capacity == 0 && len > 0) {
// end-of-file reached
return -1;
}
len = capacity;
}
if (len > 0) {
System.arraycopy(this.bytes, this.pos, b, off, len);
this.pos += len;
return len;
}
else {
return 0;
}
}
/**
* {@inheritDoc}
*/
@Override
public final long skip(long n) {
return skipOver(n, this.nBytes);
}
/**
* {@inheritDoc}
*/
@Override
public final int available() {
return (this.nBytes - this.pos);
}
/**
* Get the current position in the byte[].
*/
public final int position() {
return this.pos;
}
/**
* Set the current position in the byte[].
*/
public final void setPosition(int pos) {
this.pos = pos;
}
/**
* {@inheritDoc}
*/
@Override
public final void readFully(byte[] b) throws IOException {
final int len = b.length;
System.arraycopy(this.bytes, this.pos, b, 0, len);
this.pos += len;
}
/**
* {@inheritDoc}
*/
@Override
public final void readFully(byte[] b, int off, int len) throws IOException {
if (len > 0) {
if ((this.nBytes - this.pos) >= len) {
System.arraycopy(this.bytes, this.pos, b, off, len);
this.pos += len;
}
else {
throw new EOFException();
}
}
else if (len < 0) {
throw new IndexOutOfBoundsException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final int skipBytes(int n) {
return skipOver(n, this.nBytes);
}
/**
* {@inheritDoc}
*/
@Override
public final boolean readBoolean() throws IOException {
if (this.pos < this.nBytes) {
return (this.bytes[this.pos++] != 0);
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final byte readByte() throws IOException {
if (this.pos < this.nBytes) {
return this.bytes[this.pos++];
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final int readUnsignedByte() throws IOException {
if (this.pos < this.nBytes) {
return (this.bytes[this.pos++] & 0xff);
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final short readShort() throws IOException {
if ((this.pos + 1) < this.nBytes) {
int result = (this.bytes[this.pos++] & 0xff);
return (short)((result << 8) | (this.bytes[this.pos++] & 0xff));
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final int readUnsignedShort() throws IOException {
if ((this.pos + 1) < this.nBytes) {
int result = (this.bytes[this.pos++] & 0xff);
return ((result << 8) | (this.bytes[this.pos++] & 0xff));
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public char readChar() throws IOException {
if ((this.pos + 1) < this.nBytes) {
int result = this.bytes[this.pos++] << 8;
return (char)(result | (this.bytes[this.pos++] & 0xff));
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public int readInt() throws IOException {
if ((this.pos + 3) < this.nBytes) {
int result = (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
return ((result << 8) | (this.bytes[this.pos++] & 0xff));
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final long readLong() throws IOException {
if ((this.pos + 7) < this.nBytes) {
long result = (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
result = (result << 8) | (this.bytes[this.pos++] & 0xff);
return ((result << 8) | (this.bytes[this.pos++] & 0xff));
}
else {
throw new EOFException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final float readFloat() throws IOException {
return Float.intBitsToFloat(readInt());
}
/**
* {@inheritDoc}
*/
@Override
public final double readDouble() throws IOException {
return Double.longBitsToDouble(readLong());
}
/**
* {@inheritDoc}
*/
@Override
public final String readUTF() throws IOException {
return super.readUTF(this.bytes, this.nBytes);
}
/**
* {@inheritDoc}
*/
@Override
public void close() {
super.close();
this.bytes = null;
this.nBytes = 0;
this.version = null;
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return this.version == null ? super.toString() : (super.toString() + " ("
+ this.version + ')');
}
}