--- a/modules/libmar/src/mar_read.c
+++ b/modules/libmar/src/mar_read.c
@@ -21,17 +21,17 @@
    bytes above from the additionalBlockSize: We subtract
    sizeof(additionalBlockSize) and sizeof(additionalBlockID) */
 #define MAXADDITIONALBLOCKSIZE 96
 
 static uint32_t mar_hash_name(const char* name) {
   return CityHash64(name, strlen(name)) % TABLESIZE;
 }
 
-static int mar_insert_item(MarFile* mar, const char* name, int namelen,
+static int mar_insert_item(MarFile* mar, const char* name, uint32_t namelen,
                            uint32_t offset, uint32_t length, uint32_t flags) {
   MarItem *item, *root;
   uint32_t hash;
 
   item = (MarItem*)malloc(sizeof(MarItem) + namelen);
   if (!item) {
     return -1;
   }