com.github.ykiselev.binary.format.Types Maven / Gradle / Ivy

/*
 * Copyright 2016 Yuriy Kiselev [email protected]
 *
 * 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 com.github.ykiselev.binary.format;

/**
 * Each serialized property is stored as a pair of header and data.
 * Where header has size of one byte and data can vary from zero to N bytes.
 * Header consist of two parts - lower four bits encode property type (see below)
 * and higher four bits encode element type for arrays.
 * 
 * Created by Y.Kiselev on 26.06.2016.
 */
public final class Types {

    /**
     * Type mask, first four bits
     */
    public static final byte MASK = 0xf;

    /**
     * TYPE(1b), VALUE(1b)
     */
    public static final byte BYTE = 1;

    /**
     * TYPE(1b), VALUE(2b)
     */
    public static final byte CHAR = 2;

    /**
     * TYPE(1b), VALUE(2b)
     */
    public static final byte SHORT = 3;

    /**
     * TYPE(1b), VALUE(4b)
     */
    public static final byte INT = 4;

    /**
     * TYPE(1b), VALUE(8b)
     */
    public static final byte LONG = 5;

    /**
     * TYPE(1b), VALUE(4b)
     */
    public static final byte FLOAT = 6;

    /**
     * TYPE(1b), VALUE(8b)
     */
    public static final byte DOUBLE = 7;

    /**
     * UTF-8 string
     * TYPE(1b), LENGTH(1-4b), VALUE(n)
     */
    public static final byte STRING = 8;

    /**
     * TYPE(bits 0-3), ELEMENT_TYPE(bits 4-7), LENGTH_IN_ELEMENTS(1-4b), VALUE(n)
     */
    public static final byte ARRAY = 9;

    /**
     * TYPE(1b)
     */
    public static final byte NULL = 10;

    /**
     * TYPE(1b), 0..N * ( TYPE(1b), VALUE( f(type) ) ), END_MARKER
     */
    public static final byte USER_TYPE = 11;

    /**
     * TYPE(1b)
     */
    public static final byte END_MARKER = 12;

    /**
     * TYPE(bits 0-3) VALUE(bit 4) RESERVED(bits 5-7)
     */
    public static final byte BOOLEAN = 13;

    /**
     * Checks if supplied type is an array
     *
     * @param value the type byte
     * @return true if this is array, false otherwise
     */
    public static boolean isArray(int value) {
        return ((value & Types.MASK) == Types.ARRAY);
    }

    /**
     * Extracts sub type (higher four bits) from type byte
     *
     * @param value the type byte
     * @return the sub type
     */
    public static int subType(int value) {
        return ((value >>> 4) & Types.MASK);
    }

    /**
     * Combines array type with item type in single byte
     *
     * @param itemType the type of array item
     */
    public static byte array(int itemType) {
        final int it = itemType & Types.MASK;
        if (it != itemType) {
            throw new IllegalArgumentException("Bad item type: " + itemType);
        }
        return (byte) (Types.ARRAY + (itemType << 4));
    }
}