diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..7fff77f
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,87 @@
+// Copyright 2019 Joe Drago. All rights reserved.
+// SPDX-License-Identifier: BSD-2-Clause
+
+#include "avif/internal.h"
+
+#include <math.h>
+#include <string.h>
+
+float avifRoundf(float v)
+{
+    return floorf(v + 0.5f);
+}
+
+// Thanks, Rob Pike! https://commandcenter.blogspot.nl/2012/04/byte-order-fallacy.html
+
+uint16_t avifHTONS(uint16_t s)
+{
+    uint8_t data[2];
+    data[0] = (s >> 8) & 0xff;
+    data[1] = (s >> 0) & 0xff;
+    uint16_t result;
+    memcpy(&result, data, sizeof(uint16_t));
+    return result;
+}
+
+uint16_t avifNTOHS(uint16_t s)
+{
+    uint8_t data[2];
+    memcpy(&data, &s, sizeof(data));
+
+    return (uint16_t)((data[1] << 0)
+                      | (data[0] << 8));
+}
+
+uint32_t avifHTONL(uint32_t l)
+{
+    uint8_t data[4];
+    data[0] = (l >> 24) & 0xff;
+    data[1] = (l >> 16) & 0xff;
+    data[2] = (l >> 8) & 0xff;
+    data[3] = (l >> 0) & 0xff;
+    uint32_t result;
+    memcpy(&result, data, sizeof(uint32_t));
+    return result;
+}
+
+uint32_t avifNTOHL(uint32_t l)
+{
+    uint8_t data[4];
+    memcpy(&data, &l, sizeof(data));
+
+    return ((uint32_t)data[3] << 0)
+           | ((uint32_t)data[2] << 8)
+           | ((uint32_t)data[1] << 16)
+           | ((uint32_t)data[0] << 24);
+}
+
+uint64_t avifHTON64(uint64_t l)
+{
+    uint8_t data[8];
+    data[0] = (l >> 56) & 0xff;
+    data[1] = (l >> 48) & 0xff;
+    data[2] = (l >> 40) & 0xff;
+    data[3] = (l >> 32) & 0xff;
+    data[4] = (l >> 24) & 0xff;
+    data[5] = (l >> 16) & 0xff;
+    data[6] = (l >> 8) & 0xff;
+    data[7] = (l >> 0) & 0xff;
+    uint64_t result;
+    memcpy(&result, data, sizeof(uint64_t));
+    return result;
+}
+
+uint64_t avifNTOH64(uint64_t l)
+{
+    uint8_t data[8];
+    memcpy(&data, &l, sizeof(data));
+
+    return ((uint64_t)data[7] << 0)
+           | ((uint64_t)data[6] << 8)
+           | ((uint64_t)data[5] << 16)
+           | ((uint64_t)data[4] << 24)
+           | ((uint64_t)data[3] << 32)
+           | ((uint64_t)data[2] << 40)
+           | ((uint64_t)data[1] << 48)
+           | ((uint64_t)data[0] << 56);
+}