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/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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.
*/
package org.jboss.marshalling;
import java.io.DataInput;
import java.io.EOFException;
import java.io.IOException;
/**
* A simple base implementation of {@link DataInput} which wraps a {@link ByteInput}. This implementation maintains
* an internal buffer.
*/
public class SimpleDataInput extends ByteInputStream implements DataInput {
/**
* The internal buffer.
*/
protected final byte[] buffer;
/**
* The buffer position.
*/
protected int position;
/**
* The buffer limit.
*/
protected int limit;
/**
* Total number of bytes read and skipped from the beginning.
*/
protected long totalBytesRead;
/**
* Construct a new instance which wraps nothing.
*
* @param bufferSize the internal buffer size to use
*/
public SimpleDataInput(int bufferSize) {
this(bufferSize, null);
}
/**
* Construct a new instance.
*
* @param bufferSize the internal buffer size to use
* @param byteInput the byte input to initially wrap
*/
public SimpleDataInput(int bufferSize, ByteInput byteInput) {
super(byteInput);
buffer = new byte[bufferSize];
this.byteInput = byteInput;
}
/**
* Construct a new instance. A default buffer size is used.
*
* @param byteInput the byte input to initially wrap
*/
public SimpleDataInput(final ByteInput byteInput) {
this(8192, byteInput);
}
/** {@inheritDoc} */
public int read() throws IOException {
final int limit = this.limit;
if (limit == -1) {
return -1;
}
final int position = this.position;
final byte[] buffer = this.buffer;
if (position == limit) {
final int bytesRead = byteInput.read((buffer));
if ((this.limit = bytesRead) == -1) {
this.position = 0;
return -1;
} else {
totalBytesRead += bytesRead;
this.position = 1;
return buffer[0] & 0xff;
}
} else {
this.position = position + 1;
return buffer[position] & 0xff;
}
}
/** {@inheritDoc} */
public int read(final byte[] b) throws IOException {
return read(b, 0, b.length);
}
/** {@inheritDoc} */
public int read(final byte[] b, final int off, final int len) throws IOException {
final int limit = this.limit;
if (limit == -1) {
return -1;
}
final int position = this.position;
final int remaining = limit - position;
// pass through if the buffer is empty
if (remaining == 0) {
final int bytesRead = byteInput.read(b, off, len);
if (bytesRead != -1) {
totalBytesRead += bytesRead;
}
return bytesRead;
}
final byte[] buffer = this.buffer;
if (len > remaining) {
System.arraycopy(buffer, position, b, off, remaining);
this.limit = this.position = 0;
final int res = byteInput.read(b, off + remaining, len - remaining);
if (res == -1) {
return remaining;
} else {
totalBytesRead += res;
return res + remaining;
}
} else {
System.arraycopy(buffer, position, b, off, len);
this.position += len;
return len;
}
}
/** {@inheritDoc} */
public long skip(final long n) throws IOException {
if (n < 0) {
throw new IllegalArgumentException("n < 0");
}
final int limit = this.limit;
if (limit == -1) {
return 0L;
}
final long remaining = limit - position;
if (remaining > n) {
position += (int) n;
return n;
} else {
position = this.limit = 0;
long result = byteInput.skip(n - remaining) + remaining;
totalBytesRead += result;
return result;
}
}
/** {@inheritDoc} */
public int available() throws IOException {
return limit - position + byteInput.available();
}
private static EOFException eofOnRead() {
return new EOFException("Read past end of file");
}
/** {@inheritDoc} */
public void readFully(final byte[] b) throws IOException {
readFully(b, 0, b.length);
}
/** {@inheritDoc} */
public void readFully(final byte[] b, int off, int len) throws IOException {
if (limit == -1) {
throw eofOnRead();
}
final int position = this.position;
int remaining = limit - position;
if (len > remaining) {
if (remaining > 0) {
System.arraycopy(buffer, position, b, off, remaining);
limit = this.position = 0;
off += remaining;
len -= remaining;
}
final ByteInput byteInput = this.byteInput;
do {
remaining = byteInput.read(b, off, len);
if (remaining == -1) {
throw eofOnRead();
} else {
totalBytesRead += remaining;
}
off += remaining;
len -= remaining;
} while (len != 0);
} else try {
System.arraycopy(buffer, position, b, off, len);
this.position = position + len;
} catch (NullPointerException e) {
throw eofOnRead();
}
}
/** {@inheritDoc} */
public int skipBytes(final int n) throws IOException {
if (n < 0) {
throw new IllegalArgumentException("n < 0");
}
final int limit = this.limit;
if (limit == -1) {
return 0;
}
final int remaining = limit - position;
if (remaining > n) {
position += n;
return n;
} else {
position = this.limit = 0;
int result = (int) (byteInput.skip(n - remaining) + remaining);
totalBytesRead += result;
return result;
}
}
/** {@inheritDoc} */
public boolean readBoolean() throws IOException {
final int limit = this.limit;
if (limit == -1) {
throw eofOnRead();
}
int position;
final byte[] buffer = this.buffer;
if ((position = this.position++) == limit) {
this.position = 1;
final int bytesRead = byteInput.read(buffer);
if ((this.limit = bytesRead) == -1) {
throw eofOnRead();
} else {
totalBytesRead += bytesRead;
}
return buffer[0] != 0;
}
this.position = position + 1;
return buffer[position] != 0;
}
/** {@inheritDoc} */
public byte readByte() throws IOException {
final int limit;
if ((limit = this.limit) == -1) {
throw eofOnRead();
}
int position;
final byte[] buffer = this.buffer;
if ((position = this.position++) == limit) {
this.position = 1;
final int bytesRead = byteInput.read(buffer);
if ((this.limit = bytesRead) == -1) {
throw eofOnRead();
} else {
totalBytesRead += bytesRead;
}
return buffer[0];
}
this.position = position + 1;
return buffer[position];
}
/** {@inheritDoc} */
public int readUnsignedByte() throws IOException {
return readUnsignedByteDirect();
}
/** {@inheritDoc} */
public short readShort() throws IOException {
int position = this.position;
int remaining = limit - position;
if (remaining < 2) {
return (short) (readUnsignedByteDirect() << 8 | readUnsignedByteDirect());
} else {
final byte[] buffer = this.buffer;
this.position = position + 2;
return (short) (buffer[position] << 8 | (buffer[position + 1] & 0xff));
}
}
/** {@inheritDoc} */
public int readUnsignedShort() throws IOException {
int position = this.position;
int remaining = limit - position;
if (remaining < 2) {
return readUnsignedByteDirect() << 8 | readUnsignedByteDirect();
} else {
final byte[] buffer = this.buffer;
this.position = position + 2;
return (buffer[position] & 0xff) << 8 | (buffer[position + 1] & 0xff);
}
}
/**
* Read an unsigned byte directly.
*
* @return the unsigned byte
* @throws IOException if an error occurs
*/
protected int readUnsignedByteDirect() throws IOException {
final int limit;
if ((limit = this.limit) == -1) {
throw eofOnRead();
}
int position;
final byte[] buffer = this.buffer;
if ((position = this.position++) == limit) {
this.position = 1;
final int bytesRead = byteInput.read(buffer);
if ((this.limit = bytesRead) == -1) {
throw eofOnRead();
} else {
totalBytesRead += bytesRead;
}
return buffer[0] & 0xff;
}
return buffer[position] & 0xff;
}
/** {@inheritDoc} */
public char readChar() throws IOException {
int position = this.position;
int remaining = limit - position;
if (remaining < 2) {
return (char) (readUnsignedByteDirect() << 8 | readUnsignedByteDirect());
} else {
final byte[] buffer = this.buffer;
this.position = position + 2;
return (char) (buffer[position] << 8 | (buffer[position + 1] & 0xff));
}
}
/** {@inheritDoc} */
public int readInt() throws IOException {
return readIntDirect();
}
public long readLong() throws IOException {
return readLongDirect();
}
/** {@inheritDoc} */
protected long readLongDirect() throws IOException {
return (long) readIntDirect() << 32L | (long) readIntDirect() & 0xffffffffL;
}
/** {@inheritDoc} */
public float readFloat() throws IOException {
return Float.intBitsToFloat(readIntDirect());
}
/**
* Read an int value.
*
* @return the value
* @throws IOException if an error occurs
*/
protected int readIntDirect() throws IOException {
int position = this.position;
int remaining = limit - position;
if (remaining < 4) {
return readUnsignedByteDirect() << 24 | readUnsignedByteDirect() << 16 | readUnsignedByteDirect() << 8 | readUnsignedByteDirect();
} else {
final byte[] buffer = this.buffer;
this.position = position + 4;
return buffer[position] << 24 | (buffer[position + 1] & 0xff) << 16 | (buffer[position + 2] & 0xff) << 8 | (buffer[position + 3] & 0xff);
}
}
/** {@inheritDoc} */
public double readDouble() throws IOException {
return Double.longBitsToDouble(readLongDirect());
}
/** {@inheritDoc} */
public String readLine() throws IOException {
throw new UnsupportedOperationException("readLine() not supported");
}
/** {@inheritDoc} */
public String readUTF() throws IOException {
return UTFUtils.readUTFBytesByByteCount(this, readUnsignedShort());
}
/** {@inheritDoc} */
public void close() throws IOException {
final ByteInput byteInput = this.byteInput;
if (byteInput != null) byteInput.close();
}
/**
* Start reading from the given input. The internal buffer is discarded.
*
* @param byteInput the new input from which to read
* @throws IOException not thrown by this implementation, but may be overridden to be thrown if a problem occurs
*/
protected void start(final ByteInput byteInput) throws IOException {
this.byteInput = byteInput;
position = limit = 0;
}
/**
* Finish reading from the current input. The internal buffer is discarded, not flushed.
*
* @throws IOException not thrown by this implementation, but may be overridden to be thrown if a problem occurs
*/
protected void finish() throws IOException {
limit = -1;
position = 0;
byteInput = null;
}
}