How to pack ARGB to one integer uniquely?

Question

I have four integer values (0 - 255) for an ARGB color map.

Now I want to make a unique float or integer of these four integers. Is it possible to do it like the fol

Answer 1

You could do this:

Assuming a, r, g and b to be of type unsigned char/uint8_t:

uint32_t color = 0;
color |= a << 24;
color |= r << 16;
color |= g << 8;
color |= b;

Or more general (a, r, g and b being of any integer type):

uint32_t color = 0;
color |= (a & 255) << 24;
color |= (r & 255) << 16;
color |= (g & 255) << 8;
color |= (b & 255);

This will give you a unique integer for every ARGB combination. You can get the values back like this:

a = (color >> 24) & 255;
r = (color >> 16) & 255;
g = (color >> 8) & 255;
b = color & 255;