### Rand.BC - Random number generator for GNU BC

# Random number generator algorithm and code  - (c) 2003- CyrekSoft
# Not guaranteed for any purpose
# Chi-square tests prove this algorithm to be favourable

# To use this library an external seed source is required!
# See the bash randbc script for an example of how to do this.

scale=100
rand_seed = 3482.2023+sqrt(8)
rand_mult = sqrt(2)+sqrt(3)
rand_smax = 2^32
rand_last = 0

define srand(x) {
  x += 20/x
  x -= 13/x
  rand_seed = x
  return 0;
}

define rand(x) {
  auto i, f, os;

  if(x<0)return srand(-x)
  if(x<1)return(rand_last)

  os = scale + 10
  scale = 0  ; i = rand_seed / 1
  scale = os ; f = rand_seed - i

  rand_seed = rand_mult * (1+i) * (1+f)

  while(rand_seed>rand_smax)rand_seed-=rand_smax

  scale = 0  ; i = rand_seed / 1
  scale = os ; f = rand_seed - i

  rand_last = f
  if(x==1){scale-=10;return(rand_last)}

  rand_last = f * x + 1
  scale = 0 ; rand_last /= 1
  scale = os - 10
  
  return(rand_last)
}