/*
* 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.cassandra.io.util;
import java.io.*;
public abstract class AbstractDataInput extends InputStream implements DataInput
{
protected abstract void seekInternal(int position);
protected abstract int getPosition();
/*
!! DataInput methods below are copied from the implementation in Apache Harmony RandomAccessFile.
*/
/**
* Reads a boolean from the current position in this file. Blocks until one
* byte has been read, the end of the file is reached or an exception is
* thrown.
*
* @return the next boolean value from this file.
* @throws java.io.EOFException
* if the end of this file is detected.
* @throws java.io.IOException
* if this file is closed or another I/O error occurs.
*/
public final boolean readBoolean() throws IOException {
int temp = this.read();
if (temp < 0) {
throw new EOFException();
}
return temp != 0;
}
/**
* Reads an 8-bit byte from the current position in this file. Blocks until
* one byte has been read, the end of the file is reached or an exception is
* thrown.
*
* @return the next signed 8-bit byte value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public final byte readByte() throws IOException {
int temp = this.read();
if (temp < 0) {
throw new EOFException();
}
return (byte) temp;
}
/**
* Reads a 16-bit character from the current position in this file. Blocks until
* two bytes have been read, the end of the file is reached or an exception is
* thrown.
*
* @return the next char value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public final char readChar() throws IOException {
int ch1 = this.read();
int ch2 = this.read();
if ((ch1 | ch2) < 0)
throw new EOFException();
return (char)((ch1 << 8) + (ch2 << 0));
}
/**
* Reads a 64-bit double from the current position in this file. Blocks
* until eight bytes have been read, the end of the file is reached or an
* exception is thrown.
*
* @return the next double value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public final double readDouble() throws IOException {
return Double.longBitsToDouble(readLong());
}
/**
* Reads a 32-bit float from the current position in this file. Blocks
* until four bytes have been read, the end of the file is reached or an
* exception is thrown.
*
* @return the next float value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public final float readFloat() throws IOException {
return Float.intBitsToFloat(readInt());
}
/**
* Reads bytes from this file into {@code buffer}. Blocks until {@code
* buffer.length} number of bytes have been read, the end of the file is
* reached or an exception is thrown.
*
* @param buffer
* the buffer to read bytes into.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
* @throws NullPointerException
* if {@code buffer} is {@code null}.
*/
public void readFully(byte[] buffer) throws IOException
{
readFully(buffer, 0, buffer.length);
}
/**
* Read bytes from this file into {@code buffer} starting at offset {@code
* offset}. This method blocks until {@code count} number of bytes have been
* read.
*
* @param buffer
* the buffer to read bytes into.
* @param offset
* the initial position in {@code buffer} to store the bytes read
* from this file.
* @param count
* the maximum number of bytes to store in {@code buffer}.
* @throws EOFException
* if the end of this file is detected.
* @throws IndexOutOfBoundsException
* if {@code offset < 0} or {@code count < 0}, or if {@code
* offset + count} is greater than the length of {@code buffer}.
* @throws IOException
* if this file is closed or another I/O error occurs.
* @throws NullPointerException
* if {@code buffer} is {@code null}.
*/
public void readFully(byte[] buffer, int offset, int count) throws IOException
{
if (buffer == null) {
throw new NullPointerException();
}
// avoid int overflow
if (offset < 0 || offset > buffer.length || count < 0
|| count > buffer.length - offset) {
throw new IndexOutOfBoundsException();
}
while (count > 0) {
int result = read(buffer, offset, count);
if (result < 0) {
throw new EOFException();
}
offset += result;
count -= result;
}
}
/**
* Reads a 32-bit integer from the current position in this file. Blocks
* until four bytes have been read, the end of the file is reached or an
* exception is thrown.
*
* @return the next int value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public int readInt() throws IOException {
int ch1 = this.read();
int ch2 = this.read();
int ch3 = this.read();
int ch4 = this.read();
if ((ch1 | ch2 | ch3 | ch4) < 0)
throw new EOFException();
return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
}
/**
* Reads a line of text form the current position in this file. A line is
* represented by zero or more characters followed by {@code '\n'}, {@code
* '\r'}, {@code "\r\n"} or the end of file marker. The string does not
* include the line terminating sequence.
* <p>
* Blocks until a line terminating sequence has been read, the end of the
* file is reached or an exception is thrown.
*
* @return the contents of the line or {@code null} if no characters have
* been read before the end of the file has been reached.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public final String readLine() throws IOException {
StringBuilder line = new StringBuilder(80); // Typical line length
boolean foundTerminator = false;
int unreadPosition = 0;
while (true) {
int nextByte = read();
switch (nextByte) {
case -1:
return line.length() != 0 ? line.toString() : null;
case (byte) '\r':
if (foundTerminator) {
seekInternal(unreadPosition);
return line.toString();
}
foundTerminator = true;
/* Have to be able to peek ahead one byte */
unreadPosition = getPosition();
break;
case (byte) '\n':
return line.toString();
default:
if (foundTerminator) {
seekInternal(unreadPosition);
return line.toString();
}
line.append((char) nextByte);
}
}
}
/**
* Reads a 64-bit long from the current position in this file. Blocks until
* eight bytes have been read, the end of the file is reached or an
* exception is thrown.
*
* @return the next long value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public long readLong() throws IOException {
return ((long)(readInt()) << 32) + (readInt() & 0xFFFFFFFFL);
}
/**
* Reads a 16-bit short from the current position in this file. Blocks until
* two bytes have been read, the end of the file is reached or an exception
* is thrown.
*
* @return the next short value from this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public short readShort() throws IOException {
int ch1 = this.read();
int ch2 = this.read();
if ((ch1 | ch2) < 0)
throw new EOFException();
return (short)((ch1 << 8) + (ch2 << 0));
}
/**
* Reads an unsigned 8-bit byte from the current position in this file and
* returns it as an integer. Blocks until one byte has been read, the end of
* the file is reached or an exception is thrown.
*
* @return the next unsigned byte value from this file as an int.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public final int readUnsignedByte() throws IOException {
int temp = this.read();
if (temp < 0) {
throw new EOFException();
}
return temp;
}
/**
* Reads an unsigned 16-bit short from the current position in this file and
* returns it as an integer. Blocks until two bytes have been read, the end of
* the file is reached or an exception is thrown.
*
* @return the next unsigned short value from this file as an int.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
*/
public int readUnsignedShort() throws IOException {
int ch1 = this.read();
int ch2 = this.read();
if ((ch1 | ch2) < 0)
throw new EOFException();
return (ch1 << 8) + (ch2 << 0);
}
/**
* Reads a string that is encoded in {@link java.io.DataInput modified UTF-8} from
* this file. The number of bytes that must be read for the complete string
* is determined by the first two bytes read from the file. Blocks until all
* required bytes have been read, the end of the file is reached or an
* exception is thrown.
*
* @return the next string encoded in {@link java.io.DataInput modified UTF-8} from
* this file.
* @throws EOFException
* if the end of this file is detected.
* @throws IOException
* if this file is closed or another I/O error occurs.
* @throws java.io.UTFDataFormatException
* if the bytes read cannot be decoded into a character string.
*/
public final String readUTF() throws IOException {
return DataInputStream.readUTF(this);
}
}