src/sd_rng.c

   1 /* copyright 2016 Apache 2 sddekit authors */
   2
   3 #include "sddekit.h"
   4
   5 #include "randomkit.h"
   6
   7 struct rng_data {
   8         uint64_t ncall;
   9         uint32_t seed;
  10         rk_state rks;
  11 };
  12
  13 static void rng_seed(sd_rng *r, uint32_t seed)
  14 {
  15         struct rng_data *d = r->ptr;
  16         d->seed = seed;
  17         d->ncall = 0;
  18         rk_seed(seed, &d->rks);
  19 }
  20
  21 static double rng_norm(sd_rng *r)
  22 {
  23         struct rng_data *d = r->ptr;
  24         return rk_gauss(&d->rks);
  25 }
  26
  27 static void rng_fill_norm(sd_rng *r, uint32_t n, double *x)
  28 {
  29         uint32_t i;
  30         struct rng_data *d = r->ptr;
  31         for (i=0; i<n; i++)
  32                 x[i] = rk_gauss(&d->rks);
  33 }
  34
  35 static void rng_free(sd_rng *r)
  36 {
  37         sd_free(r->ptr);
  38         sd_free(r);
  39 }
  40
  41 static uint32_t rng_nbytes(sd_rng *r)
  42 {
  43         (void) r;
  44         return sizeof(struct rng_data) + sizeof(sd_rng);
  45 }
  46
  47 static sd_rng rng_default = {
  48         .ptr = NULL,
  49         .seed = &rng_seed,
  50         .norm = &rng_norm,
  51         .fill_norm = &rng_fill_norm,
  52         .nbytes = &rng_nbytes,
  53         .free = &rng_free
  54 };
  55
  56 sd_rng *sd_rng_new_default()
  57 {
  58         sd_rng *r;
  59     if ((r = sd_malloc (sizeof(sd_rng))) == NULL
  60          || (*r = rng_default, 0)
  61          || (r->ptr = sd_malloc (sizeof(struct rng_data))) == NULL)
  62         {
  63                 sd_free(r);
  64                 sd_err("alloc rng failed.");
  65                 return NULL;
  66         }
  67         return r;
  68 }