1 files changed, 89 insertions, 0 deletions
diff --git a/km-rand-erand48.c b/km-rand-erand48.c
new file mode 100644
index 0000000..de84b93
--- /dev/null
+++ b/km-rand-erand48.c
@@ -0,0 +1,89 @@
+#include <stdbool.h> // bool
+#define _DEFAULT_SOURCE
+#include <stdlib.h> // drand48_r()
+#include <stdio.h> // fopen()
+#include "util.h"
+#include "km.h"
+
+// get N get_floats
+static bool
+on_get_floats(
+  km_rand_t * const rs,
+  const size_t num_vals,
+  float * const vals
+) {
+  unsigned short * const data = rs->data;
+
+  // generate results
+  for (size_t i = 0; i < num_vals; i++) {
+    vals[i] = erand48(data);
+  }
+
+  // return success
+  return true;
+}
+
+// fill sizes callback for system random source
+static bool
+on_get_sizes(
+  km_rand_t * const rs,
+  const size_t num_vals,
+  size_t * const vals
+) {
+  unsigned short * const data = rs->data;
+
+  // generate results
+  for (size_t i = 0; i < num_vals; i++) {
+    vals[i] = nrand48(data);
+  }
+
+  // return success
+  return true;
+}
+
+static void
+on_fini(
+  km_rand_t * const rs
+) {
+  unsigned short * data = rs->data;
+
+  // free rng data
+  free(data);
+
+  // clear pointer
+  rs->data = NULL;
+}
+
+// path random source callbacks
+static const km_rand_cbs_t
+ERAND48_RAND_CBS = {
+  .get_floats = on_get_floats,
+  .get_sizes  = on_get_sizes,
+  .fini       = on_fini,
+};
+
+// init system random source (uses system rand())
+bool
+km_rand_init_erand48(
+  km_rand_t * const rs,
+  const uint64_t seed
+) {
+  // alloc rng data
+  unsigned short * const data = malloc(3 * sizeof(unsigned short));
+  if (!data) {
+    // return failure
+    return false;
+  }
+
+  // populate seed
+  data[0] = seed & 0xffff;
+  data[1] = (seed >> 16) & 0xffff;
+  data[2] = (seed >> 32) & 0xffff;
+
+  // populate context
+  rs->cbs = &ERAND48_RAND_CBS;
+  rs->data = data;
+
+  // return success
+  return true;
+}