1 /* encode.c -- encoding and decoding of CoAP data types
2  *
3  * Copyright (C) 2010,2011 Olaf Bergmann <bergmann@tzi.org>
4  *
5  * This file is part of the CoAP library libcoap. Please see
6  * README for terms of use.
7  */
8 
9 #ifndef NDEBUG
10 #  include <stdio.h>
11 #endif
12 
13 #include "coap_config.h"
14 #include "encode.h"
15 
16 /* Carsten suggested this when fls() is not available: */
coap_fls(unsigned int i)17 int coap_fls(unsigned int i) {
18   int n;
19   for (n = 0; i; n++)
20     i >>= 1;
21   return n;
22 }
23 
24 unsigned int
coap_decode_var_bytes(unsigned char * buf,unsigned int len)25 coap_decode_var_bytes(unsigned char *buf,unsigned int len) {
26   unsigned int i, n = 0;
27   for (i = 0; i < len; ++i)
28     n = (n << 8) + buf[i];
29 
30   return n;
31 }
32 
33 unsigned int
coap_encode_var_bytes(unsigned char * buf,unsigned int val)34 coap_encode_var_bytes(unsigned char *buf, unsigned int val) {
35   unsigned int n, i;
36 
37   for (n = 0, i = val; i && n < sizeof(val); ++n)
38     i >>= 8;
39 
40   i = n;
41   while (i--) {
42     buf[i] = val & 0xff;
43     val >>= 8;
44   }
45 
46   return n;
47 }
48 
49