Module onejoker::utils

wiki | General utility functions

Functions that are probably available in the standard libraries for general use, but implemented here to be more specifically tailored and optimized for card games.

Constants

• COEFFICIENTS
  Lookup table for binomial coefficients up to 63c63, calculated additively with Pascal’s triangle method at compile time.

Functions

• oj_binomial
  wiki | Calculate binomial coefficient Calculate the binomial coefficient “n choose k” using a lookup table. Is only valid for n, k in the range 0..=63.
• oj_next_combination
  wiki | Iterate over combinations Given an array of indices into a larger array, increment the 0-based indices to the next k-combination, returning true when done.
• oj_rand_next32
  wiki | A simple xoshiro128++ PRNG I know, I know, first rule of PRNG club is don’t roll your own, just use the library. But I’m pretty sure I’m one of the few people who understands this stuff well enough to bend that rule a bit, and I just don’t like the standard library of either Dart or Rust for this application.
• oj_rand_range
  wiki | Random integer within range Return a random integer uniformly distributed in range [0, limit) with no division, using rejection sampling. The mask m is created to minimize rejections, which will be at worst 50%.
• oj_shuffle
  wiki | Standard Fisher-Yates shuffle
• oj_sort
  wiki | Slightly specialized heapsort Heapsort optimized for small sets like poker hands, and in descending order which is most useful for ranking and displaying poker hands.