com.orientechnologies.common.util.OByteBufferUtils Maven / Gradle / Ivy
/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * 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.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.common.util;
import java.nio.ByteBuffer;
/**
* This class is utility class for split primitive types to separate byte buffers and vice versa. This class is used because we use
* many byte buffers for mmap and there is situation when we need to write value on border of two buffers.
*
* @author Artem Loginov ([email protected])
* @since 5/25/12 6:37 AM
*/
public class OByteBufferUtils {
public static final int SIZE_OF_SHORT = 2;
public static final int SIZE_OF_INT = 4;
public static final int SIZE_OF_LONG = 8;
private static final int SIZE_OF_BYTE_IN_BITS = 8;
private static final int MASK = 0x000000FF;
/**
* Merge short value from two byte buffer. First byte of short will be extracted from first byte buffer and second from second
* one.
*
* @param buffer
* to read first part of value
* @param buffer1
* to read second part of value
* @return merged value
*/
public static short mergeShortFromBuffers(final ByteBuffer buffer, final ByteBuffer buffer1) {
short result = 0;
result = (short) (result | (buffer.get() & MASK));
result = (short) (result << SIZE_OF_BYTE_IN_BITS);
result = (short) (result | (buffer1.get() & MASK));
return result;
}
/**
* Merge int value from two byte buffer. First bytes of int will be extracted from first byte buffer and second from second one.
* How many bytes will be read from first buffer determines based on buffer.remaining() value
*
* @param buffer
* to read first part of value
* @param buffer1
* to read second part of value
* @return merged value
*/
public static int mergeIntFromBuffers(final ByteBuffer buffer, final ByteBuffer buffer1) {
int result = 0;
final int remaining = buffer.remaining();
for (int i = 0; i < remaining; ++i) {
result = result | (buffer.get() & MASK);
result = result << SIZE_OF_BYTE_IN_BITS;
}
for (int i = 0; i < SIZE_OF_INT - remaining - 1; ++i) {
result = result | (buffer1.get() & MASK);
result = result << SIZE_OF_BYTE_IN_BITS;
}
result = result | (buffer1.get() & MASK);
return result;
}
/**
* Merge long value from two byte buffer. First bytes of long will be extracted from first byte buffer and second from second one.
* How many bytes will be read from first buffer determines based on buffer.remaining() value
*
* @param buffer
* to read first part of value
* @param buffer1
* to read second part of value
* @return merged value
*/
public static long mergeLongFromBuffers(final ByteBuffer buffer, final ByteBuffer buffer1) {
long result = 0;
final int remaining = buffer.remaining();
for (int i = 0; i < remaining; ++i) {
result = result | (MASK & buffer.get());
result = result << SIZE_OF_BYTE_IN_BITS;
}
for (int i = 0; i < SIZE_OF_LONG - remaining - 1; ++i) {
result = result | (MASK & buffer1.get());
result = result << SIZE_OF_BYTE_IN_BITS;
}
result = result | (MASK & buffer1.get());
return result;
}
/**
* Split short value into two byte buffer. First byte of short will be written to first byte buffer and second to second one.
*
* @param buffer
* to write first part of value
* @param buffer1
* to write second part of value
*/
public static void splitShortToBuffers(final ByteBuffer buffer, final ByteBuffer buffer1, final short iValue) {
buffer.put((byte) (MASK & (iValue >>> SIZE_OF_BYTE_IN_BITS)));
buffer1.put((byte) (MASK & iValue));
}
/**
* Split int value into two byte buffer. First byte of int will be written to first byte buffer and second to second one. How many
* bytes will be written to first buffer determines based on buffer.remaining() value
*
* @param buffer
* to write first part of value
* @param buffer1
* to write second part of value
*/
public static void splitIntToBuffers(final ByteBuffer buffer, final ByteBuffer buffer1, final int iValue) {
final int remaining = buffer.remaining();
int i;
for (i = 0; i < remaining; ++i) {
buffer.put((byte) (MASK & (iValue >>> SIZE_OF_BYTE_IN_BITS * (SIZE_OF_INT - i - 1))));
}
for (int j = 0; j < SIZE_OF_INT - remaining; ++j) {
buffer1.put((byte) (MASK & (iValue >>> SIZE_OF_BYTE_IN_BITS * (SIZE_OF_INT - i - j - 1))));
}
}
/**
* Split long value into two byte buffer. First byte of long will be written to first byte buffer and second to second one. How
* many bytes will be written to first buffer determines based on buffer.remaining() value
*
* @param buffer
* to write first part of value
* @param buffer1
* to write second part of value
*/
public static void splitLongToBuffers(final ByteBuffer buffer, final ByteBuffer buffer1, final long iValue) {
final int remaining = buffer.remaining();
int i;
for (i = 0; i < remaining; ++i) {
buffer.put((byte) (iValue >> SIZE_OF_BYTE_IN_BITS * (SIZE_OF_LONG - i - 1)));
}
for (int j = 0; j < SIZE_OF_LONG - remaining; ++j) {
buffer1.put((byte) (iValue >> SIZE_OF_BYTE_IN_BITS * (SIZE_OF_LONG - i - j - 1)));
}
}
}