diff --git a/fuzzing/fuzz_encoder.c b/fuzzing/fuzz_encoder.c
index dea288c..4f8cefc 100644
--- a/fuzzing/fuzz_encoder.c
+++ b/fuzzing/fuzz_encoder.c
@@ -4,33 +4,38 @@
 
 #include "../src/binn.c"
 
-static binn* create_list(const unsigned char *buf, unsigned int len);
-static binn* create_map(const unsigned char *buf, unsigned int len);
-static binn* create_object(const unsigned char *buf, unsigned int len);
+struct buf {
+  const unsigned char *ptr;
+  unsigned int len;
+};
 
-static binn* create_list(const unsigned char *buf, unsigned int len) {
+static binn* create_list(struct buf *buf);
+static binn* create_map(struct buf *buf);
+static binn* create_object(struct buf *buf);
+
+static binn* create_list(struct buf *buf) {
   unsigned short value_size;
   char *value;
   binn *item;
 
   binn *list = binn_list();
 
-  while(len >= 2) {
-    unsigned char value_type = *buf; buf++; len--;
+  while(buf->len >= 2) {
+    unsigned char value_type = *buf->ptr; buf->ptr++; buf->len--;
 
     switch(value_type) {
     case 1:
-      item = create_list(buf, len);
+      item = create_list(buf);
       binn_list_add_list(list, item);
       binn_free(item);
       break;
     case 2:
-      item = create_map(buf, len);
+      item = create_map(buf);
       binn_list_add_map(list, item);
       binn_free(item);
       break;
     case 3:
-      item = create_object(buf, len);
+      item = create_object(buf);
       binn_list_add_object(list, item);
       binn_free(item);
       break;
@@ -38,78 +43,78 @@ static binn* create_list(const unsigned char *buf, unsigned int len) {
       binn_list_add_null(list);
       break;
     case 5:
-      if (len < 1) goto done;
-      binn_list_add_bool(list, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_list_add_bool(list, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 6:
-      if (len < 1) goto done;
-      binn_list_add_int8(list, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_list_add_int8(list, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 7:
-      if (len < 1) goto done;
-      binn_list_add_uint8(list, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_list_add_uint8(list, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 8:
-      if (len < 2) goto done;
-      binn_list_add_int16(list, *(short*)buf);
-      buf += 2; len -= 2;
+      if (buf->len < 2) goto done;
+      binn_list_add_int16(list, *(short*)buf->ptr);
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 9:
-      if (len < 2) goto done;
-      binn_list_add_uint16(list, *(unsigned short*)buf);
-      buf += 2; len -= 2;
+      if (buf->len < 2) goto done;
+      binn_list_add_uint16(list, *(unsigned short*)buf->ptr);
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 10:
-      if (len < 4) goto done;
-      binn_list_add_int32(list, *(int*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_list_add_int32(list, *(int*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 11:
-      if (len < 4) goto done;
-      binn_list_add_uint32(list, *(unsigned int*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_list_add_uint32(list, *(unsigned int*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 12:
-      if (len < 8) goto done;
-      binn_list_add_int64(list, *(long long*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_list_add_int64(list, *(long long*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 13:
-      if (len < 8) goto done;
-      binn_list_add_uint64(list, *(unsigned long long*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_list_add_uint64(list, *(unsigned long long*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 14:
-      if (len < 4) goto done;
-      binn_list_add_float(list, *(float*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_list_add_float(list, *(float*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 15:
-      if (len < 8) goto done;
-      binn_list_add_double(list, *(double*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_list_add_double(list, *(double*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 16: // string
       // the value can be up to 16-bit size
-      if (len < 2) goto done;
-      value_size = *(unsigned short*)buf;
+      if (buf->len < 2) goto done;
+      value_size = *(unsigned short*)buf->ptr;
       value = (char*)malloc(value_size+1); // random content
       value[value_size] = 0; // null terminator
       binn_list_add_str(list, value);
       free(value);
-      buf += 2; len -= 2;
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 17: // blob
       // the value can be up to 16-bit size
-      if (len < 2) goto done;
-      value_size = *(unsigned short*)buf;
+      if (buf->len < 2) goto done;
+      value_size = *(unsigned short*)buf->ptr;
       value = (char*)malloc(value_size); // random content
       binn_list_add_blob(list, value, value_size);
       free(value);
-      buf += 2; len -= 2;
+      buf->ptr += 2; buf->len -= 2;
       break;
     //default:
     //  ...
@@ -120,30 +125,30 @@ static binn* create_list(const unsigned char *buf, unsigned int len) {
   return list;
 }
 
-static binn* create_map(const unsigned char *buf, unsigned int len) {
+static binn* create_map(struct buf *buf) {
   unsigned short value_size;
   char *value;
   binn *item;
 
   binn *map = binn_map();
 
-  while(len >= 5) {
-    int key = *(int*)buf; buf += 4; len -= 4;
-    unsigned char value_type = *buf; buf++; len--;
+  while(buf->len >= 5) {
+    int key = *(int*)buf->ptr; buf->ptr += 4; buf->len -= 4;
+    unsigned char value_type = *buf->ptr; buf->ptr++; buf->len--;
 
     switch(value_type) {
     case 1:
-      item = create_list(buf, len);
+      item = create_list(buf);
       binn_map_set_list(map, key, item);
       binn_free(item);
       break;
     case 2:
-      item = create_map(buf, len);
+      item = create_map(buf);
       binn_map_set_map(map, key, item);
       binn_free(item);
       break;
     case 3:
-      item = create_object(buf, len);
+      item = create_object(buf);
       binn_map_set_object(map, key, item);
       binn_free(item);
       break;
@@ -151,78 +156,78 @@ static binn* create_map(const unsigned char *buf, unsigned int len) {
       binn_map_set_null(map, key);
       break;
     case 5:
-      if (len < 1) goto done;
-      binn_map_set_bool(map, key, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_map_set_bool(map, key, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 6:
-      if (len < 1) goto done;
-      binn_map_set_int8(map, key, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_map_set_int8(map, key, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 7:
-      if (len < 1) goto done;
-      binn_map_set_uint8(map, key, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_map_set_uint8(map, key, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 8:
-      if (len < 2) goto done;
-      binn_map_set_int16(map, key, *(short*)buf);
-      buf += 2; len -= 2;
+      if (buf->len < 2) goto done;
+      binn_map_set_int16(map, key, *(short*)buf->ptr);
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 9:
-      if (len < 2) goto done;
-      binn_map_set_uint16(map, key, *(unsigned short*)buf);
-      buf += 2; len -= 2;
+      if (buf->len < 2) goto done;
+      binn_map_set_uint16(map, key, *(unsigned short*)buf->ptr);
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 10:
-      if (len < 4) goto done;
-      binn_map_set_int32(map, key, *(int*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_map_set_int32(map, key, *(int*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 11:
-      if (len < 4) goto done;
-      binn_map_set_uint32(map, key, *(unsigned int*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_map_set_uint32(map, key, *(unsigned int*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 12:
-      if (len < 8) goto done;
-      binn_map_set_int64(map, key, *(long long*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_map_set_int64(map, key, *(long long*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 13:
-      if (len < 8) goto done;
-      binn_map_set_uint64(map, key, *(unsigned long long*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_map_set_uint64(map, key, *(unsigned long long*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 14:
-      if (len < 4) goto done;
-      binn_map_set_float(map, key, *(float*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_map_set_float(map, key, *(float*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 15:
-      if (len < 8) goto done;
-      binn_map_set_double(map, key, *(double*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_map_set_double(map, key, *(double*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 16: // string
       // the value can be up to 16-bit size
-      if (len < 2) goto done;
-      value_size = *(unsigned short*)buf;
+      if (buf->len < 2) goto done;
+      value_size = *(unsigned short*)buf->ptr;
       value = (char*)malloc(value_size+1); // random content
       value[value_size] = 0; // null terminator
       binn_map_set_str(map, key, value);
       free(value);
-      buf += 2; len -= 2;
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 17: // blob
       // the value can be up to 16-bit size
-      if (len < 2) goto done;
-      value_size = *(unsigned short*)buf;
+      if (buf->len < 2) goto done;
+      value_size = *(unsigned short*)buf->ptr;
       value = (char*)malloc(value_size); // random content
       binn_map_set_blob(map, key, value, value_size);
       free(value);
-      buf += 2; len -= 2;
+      buf->ptr += 2; buf->len -= 2;
       break;
     //default:
     //  ...
@@ -233,35 +238,35 @@ static binn* create_map(const unsigned char *buf, unsigned int len) {
   return map;
 }
 
-static binn* create_object(const unsigned char *buf, unsigned int len) {
-  char key[256]; // random content
+static binn* create_object(struct buf *buf) {
+  char key[256];
   unsigned short value_size;
   char *value;
   binn *item;
 
   binn *obj = binn_object();
 
-  while(len >= 3) {
-    unsigned char key_size = *buf; buf++; len--;
-    if (len < key_size + 1) goto done;
-    memcpy(key, buf, key_size); buf += key_size; len -= key_size;
+  while(buf->len >= 3) {
+    unsigned char key_size = *buf->ptr; buf->ptr++; buf->len--;
+    if (buf->len < key_size + 1) goto done;
+    memcpy(key, buf->ptr, key_size); buf->ptr += key_size; buf->len -= key_size;
     key[key_size] = 0;
 
-    unsigned char value_type = *buf; buf++; len--;
+    unsigned char value_type = *buf->ptr; buf->ptr++; buf->len--;
 
     switch(value_type) {
     case 1:
-      item = create_list(buf, len);
+      item = create_list(buf);
       binn_object_set_list(obj, key, item);
       binn_free(item);
       break;
     case 2:
-      item = create_map(buf, len);
+      item = create_map(buf);
       binn_object_set_map(obj, key, item);
       binn_free(item);
       break;
     case 3:
-      item = create_object(buf, len);
+      item = create_object(buf);
       binn_object_set_object(obj, key, item);
       binn_free(item);
       break;
@@ -269,78 +274,78 @@ static binn* create_object(const unsigned char *buf, unsigned int len) {
       binn_object_set_null(obj, key);
       break;
     case 5:
-      if (len < 1) goto done;
-      binn_object_set_bool(obj, key, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_object_set_bool(obj, key, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 6:
-      if (len < 1) goto done;
-      binn_object_set_int8(obj, key, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_object_set_int8(obj, key, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 7:
-      if (len < 1) goto done;
-      binn_object_set_uint8(obj, key, *buf);
-      buf++; len--;
+      if (buf->len < 1) goto done;
+      binn_object_set_uint8(obj, key, *buf->ptr);
+      buf->ptr++; buf->len--;
       break;
     case 8:
-      if (len < 2) goto done;
-      binn_object_set_int16(obj, key, *(short*)buf);
-      buf += 2; len -= 2;
+      if (buf->len < 2) goto done;
+      binn_object_set_int16(obj, key, *(short*)buf->ptr);
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 9:
-      if (len < 2) goto done;
-      binn_object_set_uint16(obj, key, *(unsigned short*)buf);
-      buf += 2; len -= 2;
+      if (buf->len < 2) goto done;
+      binn_object_set_uint16(obj, key, *(unsigned short*)buf->ptr);
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 10:
-      if (len < 4) goto done;
-      binn_object_set_int32(obj, key, *(int*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_object_set_int32(obj, key, *(int*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 11:
-      if (len < 4) goto done;
-      binn_object_set_uint32(obj, key, *(unsigned int*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_object_set_uint32(obj, key, *(unsigned int*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 12:
-      if (len < 8) goto done;
-      binn_object_set_int64(obj, key, *(long long*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_object_set_int64(obj, key, *(long long*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 13:
-      if (len < 8) goto done;
-      binn_object_set_uint64(obj, key, *(unsigned long long*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_object_set_uint64(obj, key, *(unsigned long long*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 14:
-      if (len < 4) goto done;
-      binn_object_set_float(obj, key, *(float*)buf);
-      buf += 4; len -= 4;
+      if (buf->len < 4) goto done;
+      binn_object_set_float(obj, key, *(float*)buf->ptr);
+      buf->ptr += 4; buf->len -= 4;
       break;
     case 15:
-      if (len < 8) goto done;
-      binn_object_set_double(obj, key, *(double*)buf);
-      buf += 8; len -= 8;
+      if (buf->len < 8) goto done;
+      binn_object_set_double(obj, key, *(double*)buf->ptr);
+      buf->ptr += 8; buf->len -= 8;
       break;
     case 16: // string
       // the value can be up to 16-bit size
-      if (len < 2) goto done;
-      value_size = *(unsigned short*)buf;
+      if (buf->len < 2) goto done;
+      value_size = *(unsigned short*)buf->ptr;
       value = (char*)malloc(value_size+1); // random content
       value[value_size] = 0; // null terminator
       binn_object_set_str(obj, key, value);
       free(value);
-      buf += 2; len -= 2;
+      buf->ptr += 2; buf->len -= 2;
       break;
     case 17: // blob
       // the value can be up to 16-bit size
-      if (len < 2) goto done;
-      value_size = *(unsigned short*)buf;
+      if (buf->len < 2) goto done;
+      value_size = *(unsigned short*)buf->ptr;
       value = (char*)malloc(value_size); // random content
       binn_object_set_blob(obj, key, value, value_size);
       free(value);
-      buf += 2; len -= 2;
+      buf->ptr += 2; buf->len -= 2;
       break;
     //default:
     //  ...
@@ -351,21 +356,22 @@ static binn* create_object(const unsigned char *buf, unsigned int len) {
   return obj;
 }
 
-static void encode_binn(const unsigned char *buf, unsigned int len){
+static void encode_binn(const unsigned char *data, unsigned int len){
+  struct buf buf = {data, len};
   binn *obj = NULL;
 
   if (len < 1) return;
-  unsigned char type = *buf; buf++; len--;
+  unsigned char type = *buf.ptr; buf.ptr++; buf.len--;
 
   switch(type % 4) {
   case 1:
-    obj = create_list(buf, len);
+    obj = create_list(&buf);
     break;
   case 2:
-    obj = create_map(buf, len);
+    obj = create_map(&buf);
     break;
   case 3:
-    obj = create_object(buf, len);
+    obj = create_object(&buf);
     break;
   }