[Gimp-developer] the indexed mode implementation

[阿四 <ashi08104 gmail com>]

Hi,all.
I'm curious about how the indexed mode in gimp is implemented. Because I implemented a function which change a RGB colorspace image to indexed color image before, but my implementation is extremely slow. The algorithm is trivial, the runtime is about O(n^k), where n is number of pixels, k is the size of index. However, I tried indexed mode in GIMP on same image on same computer, it's really faster than my implementation. 
Could anyone give me some information about the indexed mode in GIMP? Thanks!

Best Regards
--ashi