C#4位数据类型 [英] C# 4 bit data type

问题描述

C#是否具有 4位数据类型?我想用一个浪费最小内存的变量制作程序，因为该程序会消耗很多内存.

Does C# have a 4 bit data type? I want to make a program with variables that waste the minimum amount of memory, because the program will consume a lot.

例如:我需要保存一个我知道它将从 0 变为 10 的值，并且可以使用 4位变量从 0 到 15 完美.但是我发现最接近的是8位(1字节)数据类型 Byte .

For example: I need to save a value that i know it will go from 0 to 10 and a 4 bit var can go from 0 to 15 and it's perfect. But the closest i found was the 8 bit (1 Byte) data type Byte.

我有一个用自定义数据类型创建 c ++ dll 的想法.轻咬之类的东西.但是，如果这是我的问题的解决方案，那么我不知道从哪里开始以及我该怎么做.

I have the idea of creating a c++ dll with a custom data type. Something like nibble. But, if that's the solution to my problem, i don't know where to start, and what i have to do.

局限性:否是创建字节并将其分成两部分的一种选择.

Limitations: Creating a Byte and splitting it in two is NOT an option.

推荐答案

不，在c#中不存在四位数据类型的问题.

No, there is no such thing as a four-bit data type in c#.

顺便说一句，四个位将只存储一个0到15的数字，因此，如果您存储的是0到127的值，这听起来似乎不合适.N位，使用公式(2 ^ N)-1 计算最大值.2 ^ 4 = 16-1 = 15.

Incidentally, four bits will only store a number from 0 to 15, so it doesn't sound like it is fit for purpose if you are storing values from 0 to 127. To compute the range of a variable given that it has N bits, use the formula (2^N)-1 to calculate the maximum. 2^4 = 16 - 1 = 15.

如果您需要使用小于8位的数据类型以节省空间，则需要使用

If you need to use a data type that is less than 8 bits in order to save space, you will need to use a packed binary format and special code to access it.

例如，您可以使用AND掩码加上一个位移，将两个四个四位值存储在一个字节中，例如

You could for example store two four-bit values in a byte using an AND mask plus a bit shift, e.g.

byte source = 0xAD;
var hiNybble = (source & 0xF0) >> 4; //Left hand nybble = A
var loNyblle = (source & 0x0F);      //Right hand nybble = D

或者使用整数除法和模数，也可以很好地工作，但是可读性可能不高:

Or using integer division and modulus, which works well too but maybe isn't quite as readable:

var hiNybble = source / 16;
var loNybble = source % 16;

当然可以使用扩展方法.

And of course you can use an extension method.

static byte GetLowNybble(this byte input)
{
    return input % 16;
}

static byte GetHighNybble(this byte input)
{
    return input / 16;
}

var hiNybble = source.GetHighNybble();
var loNybble = source.GetLowNybble();

存储起来更容易:

var source = hiNybble * 16 + lowNybble;

仅更新一个半字节就比较困难:

Updating just one nybble is harder:

var source = source & 0xF0 + loNybble;        //Update only low four bits
var source = source & 0x0F + (hiNybble << 4); //Update only high bits

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