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The MongoDB Java Driver uber-artifact, containing mongodb-driver, mongodb-driver-core, and bson
/*
* Copyright (c) 2008-2014 MongoDB, Inc.
*
* 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.bson.io;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
/**
* Utility class for reading values from an input stream.
*/
public class Bits {
/**
* Reads bytes from the input stream and puts them into the given byte buffer. The equivalent of calling {@link
* #readFully(java.io.InputStream, byte[], int, int)} with an offset of zero and a length equal to the length of the buffer.
*
* @param in the input stream to read from
* @param b the buffer into which the data is read.
* @throws IOException if there's an error reading from the {@code in}
*/
public static void readFully(InputStream in, byte[] b) throws IOException {
readFully(in, b, b.length);
}
/**
* Reads bytes from the input stream and puts them into the given byte buffer. The equivalent of calling {@link
* #readFully(java.io.InputStream, byte[], int, int)} with an offset of zero.
*
* @param in the input stream to read from
* @param b the buffer into which the data is read.
* @param length the maximum number of bytes to read.
* @throws IOException if there's an error reading from the {@code in}
*/
public static void readFully(InputStream in, byte[] b, int length) throws IOException {
readFully(in, b, 0, length);
}
/**
* Reads bytes from the input stream and puts them into the given byte buffer.
*
* @param in the input stream to read from
* @param b the buffer into which the data is read.
* @param startOffset the start offset in array {@code b} at which the data is written.
* @param length the maximum number of bytes to read.
* @throws IOException if there's an error reading from the {@code in}
* @see java.io.InputStream#read(byte[], int, int)
*/
public static void readFully(InputStream in, byte[] b, int startOffset, int length)
throws IOException {
if (b.length < length + startOffset) {
throw new IllegalArgumentException("Buffer is too small");
}
int offset = startOffset;
int toRead = length;
while ( toRead > 0 ){
int bytesRead = in.read( b, offset , toRead );
if ( bytesRead < 0 )
throw new EOFException();
toRead -= bytesRead;
offset += bytesRead;
}
}
/**
* Reads and returns a single integer value from the input stream.
*
* @param in the input stream to read from
* @return the integer value
* @throws IOException if there's an error reading from the {@code in}
*/
public static int readInt(InputStream in) throws IOException {
return readInt(in, new byte[4]);
}
/**
* Reads and returns a single integer value from the input stream.
*
* @param in the input stream to read from
* @param data the buffer to write the input stream bytes into
* @return the integer value
* @throws IOException if there's an error reading from the {@code in}
*/
public static int readInt(InputStream in, byte[] data)
throws IOException {
readFully(in, data, 4);
return readInt(data);
}
/**
* Reads and returns a single integer value from the buffer. The equivalent of calling {@link #readInt(byte[], int)} with an offset of
* zero.
*
* @param data the buffer to read from
* @return the integer value
*/
public static int readInt(byte[] data) {
return readInt(data, 0);
}
/**
* Reads and returns a single integer value from the buffer.
*
* @param data the buffer to read from
* @param offset the position to start reading from the buffer
* @return the integer value
*/
public static int readInt(byte[] data, int offset) {
int x = 0;
x |= ( 0xFF & data[offset+0] ) << 0;
x |= ( 0xFF & data[offset+1] ) << 8;
x |= ( 0xFF & data[offset+2] ) << 16;
x |= ( 0xFF & data[offset+3] ) << 24;
return x;
}
/**
* Reads and returns a single big-endian integer value
*
* @param data the buffer to read from
* @param offset the position to start reading from the buffer
* @return the integer value
*/
public static int readIntBE(byte[] data, int offset) {
int x = 0;
x |= ( 0xFF & data[offset+0] ) << 24;
x |= ( 0xFF & data[offset+1] ) << 16;
x |= ( 0xFF & data[offset+2] ) << 8;
x |= ( 0xFF & data[offset+3] ) << 0;
return x;
}
/**
* Reads and returns a single long value from the input stream.
*
* @param in the input stream to read from
* @return the long value
* @throws IOException if there's an error reading from the {@code in}
*/
public static long readLong(InputStream in) throws IOException {
return readLong(in, new byte[8]);
}
/**
* Reads and returns a single long value from the input stream.
*
* @param in the input stream to read from
* @param data the buffer to write the input stream bytes into
* @return the long value
* @throws IOException if there's an error reading from the {@code in}
*/
public static long readLong(InputStream in, byte[] data) throws IOException {
readFully(in, data, 8);
return readLong(data);
}
/**
* Reads and returns a single long value from the buffer. The equivalent of called {@link #readLong(byte[], int)} with an offset of
* zero.
*
* @param data the buffer to read from
* @return the long value
*/
public static long readLong(byte[] data) {
return readLong(data, 0);
}
/**
* Reads and returns a single long value from the buffer.
*
* @param data the buffer to read from
* @param offset the position to start reading from the buffer
* @return the long value
*/
public static long readLong(byte[] data, int offset) {
long x = 0;
x |= ( 0xFFL & data[offset+0] ) << 0;
x |= ( 0xFFL & data[offset+1] ) << 8;
x |= ( 0xFFL & data[offset+2] ) << 16;
x |= ( 0xFFL & data[offset+3] ) << 24;
x |= ( 0xFFL & data[offset+4] ) << 32;
x |= ( 0xFFL & data[offset+5] ) << 40;
x |= ( 0xFFL & data[offset+6] ) << 48;
x |= ( 0xFFL & data[offset+7] ) << 56;
return x;
}
}
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