/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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 io.netty.buffer;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
/**
* An {@link InputStream} which reads data from a {@link ByteBuf}.
* <p>
* A read operation against this stream will occur at the {@code readerIndex}
* of its underlying buffer and the {@code readerIndex} will increase during
* the read operation. Please note that it only reads up to the number of
* readable bytes determined at the moment of construction. Therefore,
* updating {@link ByteBuf#writerIndex()} will not affect the return
* value of {@link #available()}.
* <p>
* This stream implements {@link DataInput} for your convenience.
* The endianness of the stream is not always big endian but depends on
* the endianness of the underlying buffer.
*
* @see ByteBufOutputStream
*/
public class ByteBufInputStream extends InputStream implements DataInput {
private final ByteBuf buffer;
private final int startIndex;
private final int endIndex;
/**
* Creates a new stream which reads data from the specified {@code buffer}
* starting at the current {@code readerIndex} and ending at the current
* {@code writerIndex}.
*/
public ByteBufInputStream(ByteBuf buffer) {
this(buffer, buffer.readableBytes());
}
/**
* Creates a new stream which reads data from the specified {@code buffer}
* starting at the current {@code readerIndex} and ending at
* {@code readerIndex + length}.
*
* @throws IndexOutOfBoundsException
* if {@code readerIndex + length} is greater than
* {@code writerIndex}
*/
public ByteBufInputStream(ByteBuf buffer, int length) {
if (buffer == null) {
throw new NullPointerException("buffer");
}
if (length < 0) {
throw new IllegalArgumentException("length: " + length);
}
if (length > buffer.readableBytes()) {
throw new IndexOutOfBoundsException("Too many bytes to be read - Needs "
+ length + ", maximum is " + buffer.readableBytes());
}
this.buffer = buffer;
startIndex = buffer.readerIndex();
endIndex = startIndex + length;
buffer.markReaderIndex();
}
/**
* Returns the number of read bytes by this stream so far.
*/
public int readBytes() {
return buffer.readerIndex() - startIndex;
}
@Override
public int available() throws IOException {
return endIndex - buffer.readerIndex();
}
@Override
public void mark(int readlimit) {
buffer.markReaderIndex();
}
@Override
public boolean markSupported() {
return true;
}
@Override
public int read() throws IOException {
if (!buffer.isReadable()) {
return -1;
}
return buffer.readByte() & 0xff;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
int available = available();
if (available == 0) {
return -1;
}
len = Math.min(available, len);
buffer.readBytes(b, off, len);
return len;
}
@Override
public void reset() throws IOException {
buffer.resetReaderIndex();
}
@Override
public long skip(long n) throws IOException {
if (n > Integer.MAX_VALUE) {
return skipBytes(Integer.MAX_VALUE);
} else {
return skipBytes((int) n);
}
}
@Override
public boolean readBoolean() throws IOException {
checkAvailable(1);
return read() != 0;
}
@Override
public byte readByte() throws IOException {
if (!buffer.isReadable()) {
throw new EOFException();
}
return buffer.readByte();
}
@Override
public char readChar() throws IOException {
return (char) readShort();
}
@Override
public double readDouble() throws IOException {
return Double.longBitsToDouble(readLong());
}
@Override
public float readFloat() throws IOException {
return Float.intBitsToFloat(readInt());
}
@Override
public void readFully(byte[] b) throws IOException {
readFully(b, 0, b.length);
}
@Override
public void readFully(byte[] b, int off, int len) throws IOException {
checkAvailable(len);
buffer.readBytes(b, off, len);
}
@Override
public int readInt() throws IOException {
checkAvailable(4);
return buffer.readInt();
}
private final StringBuilder lineBuf = new StringBuilder();
@Override
public String readLine() throws IOException {
lineBuf.setLength(0);
loop: while (true) {
if (!buffer.isReadable()) {
return lineBuf.length() > 0 ? lineBuf.toString() : null;
}
int c = buffer.readUnsignedByte();
switch (c) {
case '\n':
break loop;
case '\r':
if (buffer.isReadable() && (char) buffer.getUnsignedByte(buffer.readerIndex()) == '\n') {
buffer.skipBytes(1);
}
break loop;
default:
lineBuf.append((char) c);
}
}
return lineBuf.toString();
}
@Override
public long readLong() throws IOException {
checkAvailable(8);
return buffer.readLong();
}
@Override
public short readShort() throws IOException {
checkAvailable(2);
return buffer.readShort();
}
@Override
public String readUTF() throws IOException {
return DataInputStream.readUTF(this);
}
@Override
public int readUnsignedByte() throws IOException {
return readByte() & 0xff;
}
@Override
public int readUnsignedShort() throws IOException {
return readShort() & 0xffff;
}
@Override
public int skipBytes(int n) throws IOException {
int nBytes = Math.min(available(), n);
buffer.skipBytes(nBytes);
return nBytes;
}
private void checkAvailable(int fieldSize) throws IOException {
if (fieldSize < 0) {
throw new IndexOutOfBoundsException("fieldSize cannot be a negative number");
}
if (fieldSize > available()) {
throw new EOFException("fieldSize is too long! Length is " + fieldSize
+ ", but maximum is " + available());
}
}
}