node.js - 如何从 Node.js 缓冲区上的 UInt64 读取 Double？

Question

我想读取 UInt64BE 并将其转换为 Double。 我怎样才能做到这一点？

我将Double转换为UInt64BE，如下所示:

var time = Date.now();
buffer.writeUInt32BE(parseInt(time / 0xffffffff, 10), 0);
buffer.writeUInt32BE(parseInt(time & 0xffffffff, 10), 4);

Answer 1

我找到了以下解决方案:

var buffer = new Buffer(8),
    time = Date.now(),

// convert number to hex
var hex = time.toString(16);
while(hex.length < 16)
    hex = '0' + hex;

// write number as UInt64
buffer.write(hex, 0, 8, 'hex');

// read UInt64 as hex and convert to Double
var num = parseInt(buffer.toString('hex', 0, 8), 16);

console.log(num === time);