It seems that there are several really fast prime factorization algorithms around (one that looks ideal is quadratic sieving). However, rather than make my own (likely poor) implementation I would like to use a ready-made library for simplicity.
I need to be able to factor integers of up to 15 digits efficiently. Because of that, I'm not looking for the algorithm that necessarily scales asymptotically best since we can assume the numbers being factored are less than 1015.
I've already had a look at some of the implementations listed on Wikipedia's Quadratic Sieve page. However, some of the implementations don't seem well-maintained; some don't have documentation; and so on! I checked if a few well-known libraries, such as Boost, had factorization methods but they don't seem to.
Can anyone recommend a library that fits the above criteria?