org.spongepowered.common.network.ByteBufUtils.java Source code

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Here is the source code for org.spongepowered.common.network.ByteBufUtils.java

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/*
 * This file is part of Sponge, licensed under the MIT License (MIT).
 *
 * Copyright (c) SpongePowered <https://www.spongepowered.org>
 * Copyright (c) contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package org.spongepowered.common.network;

import com.google.common.base.Charsets;
import io.netty.buffer.ByteBuf;
import org.apache.commons.lang3.Validate;

// Utilities taken directly from
// net.minecraftforge.fml.common.network.ByteBufUtils
public class ByteBufUtils {

    private static int varIntByteCount(int toCount) {
        return (toCount & 0xFFFFFF80) == 0 ? 1
                : ((toCount & 0xFFFFC000) == 0 ? 2
                        : ((toCount & 0xFFE00000) == 0 ? 3 : ((toCount & 0xF0000000) == 0 ? 4 : 5)));
    }

    private static int readVarInt(ByteBuf buf, int maxSize) {
        Validate.isTrue(maxSize < 6 && maxSize > 0, "Varint length is between 1 and 5, not %d", maxSize);
        int i = 0;
        int j = 0;
        byte b0;

        do {
            b0 = buf.readByte();
            i |= (b0 & 127) << j++ * 7;

            if (j > maxSize) {
                throw new RuntimeException("VarInt too big");
            }
        } while ((b0 & 128) == 128);

        return i;
    }

    private static void writeVarInt(ByteBuf to, int toWrite, int maxSize) {
        Validate.isTrue(varIntByteCount(toWrite) <= maxSize, "Integer is too big for %d bytes", maxSize);
        while ((toWrite & -128) != 0) {
            to.writeByte(toWrite & 127 | 128);
            toWrite >>>= 7;
        }

        to.writeByte(toWrite);
    }

    public static void writeUTF8String(ByteBuf to, String string) {
        byte[] utf8Bytes = string.getBytes(Charsets.UTF_8);
        Validate.isTrue(varIntByteCount(utf8Bytes.length) < 3, "The string is too long for this encoding.");
        writeVarInt(to, utf8Bytes.length, 2);
        to.writeBytes(utf8Bytes);
    }

    public static String readUTF8String(ByteBuf from) {
        int len = readVarInt(from, 2);
        String str = from.toString(from.readerIndex(), len, Charsets.UTF_8);
        from.readerIndex(from.readerIndex() + len);
        return str;
    }

}