benchmark: parsing 3byte-uint in CoffeeScript

parse_3_byte_uint.coffee

rt = require "random-tools" # https://github.com/shinout/random-tools

N = 1000000
d = []
i = 0

# data preparation
while i < N
  n = rt.randomInt(256 * 256 * 256 - 1)
  b = new Buffer(3)
  b.writeUInt16BE(n >> 8, 0)
  b.writeUInt8(n & 0xff, 2)
  d.push [n, b, b.toString("hex")]
  i++

# parseInt 16
console.time "h"
for v in d
  h = v[2]
  n = parseInt h, 16
  #console.assert n is v[0]

console.timeEnd "h"

# reads buffer
console.time "b"
for v in d
  b = v[1]
  n = b.readUInt16BE(0) * 256 + b.readUInt8(2)
  #console.assert n is v[0]

console.timeEnd "b"
  

h: 94ms
b: 45ms

Reading integers from buffer is faster than parsing hexed string into decimal.