I'm going to proceed on the assumption that it's 10 bits red, 10 bits green and 10 bits blue -- 10 bits per pixel per channel, a total of 30 bits which will fit into a 32-bit variable.

A lookup table would require 1024 entries * 2 bytes each to hold values up to 1024. The table would thus be 2048 bytes in size. All three colors would have the same curve applied, so this table would be referred to 3 times for each pixel (r, g and b).

What format does the file take?