feature(round): Added rounding library.

The first features are:
1) Floor'ing and Ceil'ing to the next value of a specific stepping
2) Floor'ing and Ceil'ing to the next power of 2.

inc-c/ufn/ufn_round.h

@@ -0,0 +1,54 @@
+
+#ifndef UFN_ROUND_H
+#define UFN_ROUND_H
+
+#include <stdint.h>
+
+int64_t ufn_floor_i64(int64_t value, int64_t stepping);
+int64_t ufn_ceil_i64(int64_t value, int64_t stepping);
+
+uint64_t ufn_floor_pow2(uint64_t value);
+uint64_t ufn_ceil_pow2(uint64_t value);
+
+#ifdef UFN_IMPLEMENTATION
+
+int64_t ufn_floor_i64(int64_t value, int64_t stepping)
+{
+    return value - (value % stepping);
+}
+
+int64_t ufn_ceil_i64(int64_t value, int64_t stepping)
+{
+    return ufn_floor_i64(value, stepping) + stepping;
+}
+
+uint64_t ufn_floor_pow2(uint64_t value)
+{
+    // Find highest-priority bit which is 1
+
+    int8_t bit_index = 63;
+    while(bit_index >= 0)
+    {
+        if(value & (1 << bit_index))
+        {
+            break;
+        }
+        --bit_index;
+    }
+    return 1 << bit_index;
+}
+
+uint64_t ufn_ceil_pow2(uint64_t value)
+{
+    uint64_t floored = ufn_floor_pow2(value);
+    if(value == floored)
+    {
+        return value;
+    }
+    return floored * 2;
+}
+
+#endif // UFN_IMPLEMENTATION
+
+#endif // UFN_ROUND_H
+