sys/random: provide generic random_bytes()

sys/random/Makefile

@@ -1,4 +1,4 @@
-SRC := seed.c
+SRC := random.c
 
 BASE_MODULE := prng
 SUBMODULES := 1

sys/random/random.c

@@ -39,3 +39,18 @@ void auto_init_random(void)
     DEBUG("random: using seed value %u\n", (unsigned)seed);
     random_init(seed);
 }
+
+void random_bytes(uint8_t *target, size_t n)
+{
+    uint32_t random;
+    uint8_t *random_pos = (uint8_t*)&random;
+    unsigned _n = 0;
+
+    while (n--) {
+        if (! (_n++ & 0x3)) {
+            random = random_uint32();
+            random_pos = (uint8_t *) &random;
+        }
+        *target++ = *random_pos++;
+    }
+}

sys/random/tinymt32.c

@@ -44,36 +44,6 @@ uint32_t random_uint32(void)
     return tinymt32_generate_uint32(&_random);
 }
 
-void random_bytes(uint8_t *buf, size_t size)
-{
-    size_t iter = size;
-    size_t diff = _align(buf) - buf;
-    uint32_t tmp;
-
-    /* Fill first <4 unaligned bytes */
-    if (diff) {
-        tmp = tinymt32_generate_uint32(&_random);
-        if (diff > size) {
-            diff = size;
-        }
-        memcpy(buf, &tmp, diff);
-        iter -= diff;
-    }
-
-    /* Fill aligned bytes */
-    while (iter >= sizeof(uint32_t)) {
-        *((uint32_t *) buf) = tinymt32_generate_uint32(&_random);
-        buf += sizeof(uint32_t);
-        iter -= sizeof(uint32_t);
-    }
-
-    /* Fill last bytes */
-    if (iter) {
-        tmp = tinymt32_generate_uint32(&_random);
-        memcpy(buf, &tmp, iter);
-    }
-}
-
 void random_init_by_array(uint32_t init_key[], int key_length)
 {
     tinymt32_init_by_array(&_random, init_key, key_length);