如何在nodejs / javascript中获取uint256_t的上下部分，

问题描述

我有等效的c ++，但不确定如何在javascript / nodejs中实现它。

c ++：

template <unsigned int BITS>
enum { WIDTH = BITS / 32 };
uint32_t pn[WIDTH];

    uint256 seed = "00000800ab9d2c5409a9b4dea2aa6f8471cecc41b35706e6d6155098e5f3595d";

    
    uint64_t Get64(int n = 0) const
        {
            return pn[2 * n] | (uint64_t)pn[2 * n + 1] << 32;
        }
    
    uint64_t first = seed.Get64(0) % 6 + 1;
    uint64_t second = seed.Get64(1) % 6 + 1;

首先可以使用以下命令获取uint64_t。但不知道如何在第二个实施中实现。

   //uint64_t first = seed.Get64(0) % 6 + 1;    
    
    var bigInt = require("big-integer");
        var hash = bigInt("00000800ab9d2c5409a9b4dea2aa6f8471cecc41b35706e6d6155098e5f3595d",16);
        console.log(hash.and(new bigInt("ffffffffffffffff",16)).mod(6) + 1)

//result of first = 6

解决方法

如何使用JavaScript“原生” BigInt

var instances = from t in Assembly.GetExecutingAssembly().GetTypes()
                            where t.GetInterfaces().Contains(typeof(IMessage))
                                     && t.GetConstructor(Type.EmptyTypes) != null
                            select Activator.CreateInstance(t) as IMessage;

foreach (var instance in instances)
{
    string json = instance.ToString();  // doesnot work
    Console.WriteLine(instance.GetType().GetNestedTypes().ToString()); // doesnot work
}

或者，您可以做很多人认为不可以并扩展BigInt原型的事情-通常我建议扩展BigInt类，但是，据我所知，这是不可能的（因为const get64 = (value,n=0) => (value >> BigInt(64*n)) & 0xffffffffffffffffn; const toNumber = value => +value.toString(); var hash = 0x00000800ab9d2c5409a9b4dea2aa6f8471cecc41b35706e6d6155098e5f3595dn; var first = toNumber(get64(hash,0) % 6n + 1n); var second = toNumber(get64(hash,1) % 6n + 1n); console.log(first,second)是不支持）

new BigInt