如何使用Golang移位十六进制值？

Question

Let's say I have a string with the value of 4ADDF6C259EBAFF8.

Using this I want to get a timestamp, using the formula (hex(val) >> 25) + 1008000400.

Using t he encoding/hex package, I have come up with the following:

srcBytes := []byte(src)
dst := make([]byte, hex.EncodedLen(len(srcBytes)))
hex.Encode(dst, srcBytes)

After this, I need a way to bit shift dst 25 times, and then add a constant to it.

However dst is of type []byte.

I need it to be of type hex so I can bit shift after. How do I convert []byte so that it can be shifted?

Answer 1

Assuming your input string varies but has a maximum of 16 hex digits, you just convert to a 64 bit (unsigned) integer and do the math. I also prefixed your constant with 0x assuming it is hex (judging by the digits).

  s := "4ADDF6C259EBAFF8"
  if i, err := strconv.ParseUint(s, 16, 64); err == nil {
    fmt.Printf("%x
", i >> 25 + 0x1008000400)
  }

BTW hex is not a type but a way of displaying integers.