package net.minecraft.network;

import io.netty.buffer.ByteBuf;

public class VarLong {
	private static final int MAX_VARLONG_SIZE = 10;
	private static final int DATA_BITS_MASK = 127;
	private static final int CONTINUATION_BIT_MASK = 128;
	private static final int DATA_BITS_PER_BYTE = 7;

	public static int getByteSize(long data) {
		for (int i = 1; i < 10; i++) {
			if ((data & -1L << i * 7) == 0L) {
				return i;
			}
		}

		return 10;
	}

	public static boolean hasContinuationBit(byte data) {
		return (data & 128) == 128;
	}

	public static long read(ByteBuf buffer) {
		long l = 0L;
		int i = 0;

		byte b;
		do {
			b = buffer.readByte();
			l |= (long)(b & 127) << i++ * 7;
			if (i > 10) {
				throw new RuntimeException("VarLong too big");
			}
		} while (hasContinuationBit(b));

		return l;
	}

	public static ByteBuf write(ByteBuf buffer, long value) {
		while ((value & -128L) != 0L) {
			buffer.writeByte((int)(value & 127L) | 128);
			value >>>= 7;
		}

		buffer.writeByte((int)value);
		return buffer;
	}
}