1 files changed, 61 insertions, 0 deletions
diff --git a/src/core/index.c b/src/core/index.c
new file mode 100644
index 0000000..375e0ad
--- /dev/null
+++ b/src/core/index.c
@@ -0,0 +1,61 @@
+#include <limits.h>
+#include <stdlib.h>
+
+#include "index.h"
+
+#if (RAND_MAX < UCHAR_MAX)
+   #error "RAND_MAX < UCHAR_MAX, unable to generate random numbers."
+#endif
+
+#if (RAND_MAX == 0)
+   #error "RAND_MAX is included in [0, 0]. What are you even doing?"
+#endif
+
+/*
+ * Returns a random unsigned char.
+ */
+static unsigned char random_uchar (void)
+{
+   return
+   (unsigned char)
+   (
+      /* FIXME: Do floats allow enough precision for this? */
+      (
+         ((float) rand())
+         / ((float) RAND_MAX)
+      )
+      * ((float) UCHAR_MAX)
+   );
+}
+
+/* See: "index.h" */
+ZoO_index ZoO_index_random (void)
+{
+   ZoO_index i;
+   ZoO_index result;
+   unsigned char * result_bytes;
+
+   result_bytes = (unsigned char *) &result;
+
+   for (i = 0; i < sizeof(ZoO_index); ++i)
+   {
+      result_bytes[i] = random_uchar();
+   }
+
+   return result;
+}
+
+/* See: "index.h" */
+ZoO_index ZoO_index_random_up_to (const ZoO_index max)
+{
+   return
+   (ZoO_index)
+   (
+      /* FIXME: Do floats allow enough precision for this? */
+      (
+         ((float) ZoO_index_random())
+         / ((float) ZoO_INDEX_MAX)
+      )
+      * ((float) max)
+   );
+}