How to determine how many bytes an integer needs?

Question

I\'m looking for the most efficient way to calculate the minimum number of bytes needed to store an integer without losing precision.

e.g.

int: 10 = 1 byte
         


        

Answer 1

Assuming a byte is 8 bits, to represent an integer x you need [log2(x) / 8] + 1 bytes where [x] = floor(x).

Ok, I see now that the byte sizes aren't necessarily a power of two. Consider the byte sizes b. The formula is still [log2(x) / b] + 1.

Now, to calculate the log, either use lookup tables (best way speed-wise) or use binary search, which is also very fast for integers.