diff --git a/src/lib/string.c b/src/lib/string.c
index 491901d..e283d78 100644
--- a/src/lib/string.c
+++ b/src/lib/string.c
@@ -15,7 +15,7 @@ void *memcpy(void *dest, const void *src, size_t size)
 {
     unsigned char *d = dest;
     const unsigned char *s = src;
-    while (--size)
+    while (size--)
     {
         *d++ = *s++;
     }