org.jboss.ejb.protocol.remote.PackedInteger Maven / Gradle / Ivy
/*
* JBoss, Home of Professional Open Source.
* Copyright 2017 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.ejb.protocol.remote;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
/**
* A {@link PackedInteger} is a variable-length integer. The most-significant bit of each byte of a
* {@link PackedInteger} value indicates whether that byte is the final (lowest-order) byte of the value.
* If the bit is 0, then this is the last byte; if the bit is 1, then there is at least one more subsequent
* byte pending, and the current value should be shifted to the left by 7 bits to accommodate the next byte's data.
*
* Note: {@link PackedInteger} cannot hold signed integer values.
*
* @author Carlo de Wolf
*/
class PackedInteger {
/**
* Reads a {@link PackedInteger} value from the passed {@link DataInput input} and returns the
* value of the integer.
*
* @param input The {@link DataInput} from which the {@link PackedInteger} value will be read
* @return
* @throws IOException
* @throws IllegalArgumentException If the passed input is null
*/
public static int readPackedInteger(final DataInput input) throws IOException {
int b = input.readByte();
if ((b & 0x80) == 0x80) {
return readPackedInteger(input) << 7 | (b & 0x7F);
}
return b;
}
/**
* Converts the passed value into a {@link PackedInteger} and writes it to the
* {@link DataOutput output}
*
* @param output The {@link DataOutput} to which the {@link PackedInteger} is written to
* @param value The integer value which will be converted to a {@link PackedInteger}
* @throws IOException
* @throws IllegalArgumentException If the passed value is < 0. {@link PackedInteger} doesn't
* allow signed integer
* @throws IllegalArgumentException If the passed output is null
*/
public static void writePackedInteger(final DataOutput output, int value) throws IOException {
if (value < 0)
throw new IllegalArgumentException("Only unsigned integer can be packed");
if (value > 127) {
output.writeByte(value & 0x7F | 0x80);
writePackedInteger(output, value >> 7);
} else {
output.writeByte(value & 0xFF);
}
}
}