如何翻转代表 Lua 中的 8 位十六进制字符串的 integer？

Question

In my Lua script, I have a variable that stores an integer found from some function that represents a hex string. I want to flip it so that, for example, if it has a value of 0x006E57E8 , it will become 0x8E75E600 . How do I do it in Lua?

Answer 1

As an alternative to Skriptunoff's very concise & readable function, here's a function doing it using bit ops:

function reverse_nibbles(int)
    res = 0
    for i = 0, 7 do
        res = res | (((int >> (4*i)) & 0xF) << (28 - 4*i))
    end
    return res
end

This won't create a garbage string (and would hopefully be faster). You might want to hand-unroll the loop.