1/* $Id: codelength.h,v 1.3 2011/07/30 13:10:05 nanard Exp $ */
2/* Project : miniupnp
3 * Author : Thomas BERNARD
4 * copyright (c) 2005-2015 Thomas Bernard
5 * This software is subjet to the conditions detailed in the
6 * provided LICENCE file. */
7#ifndef CODELENGTH_H_INCLUDED
8#define CODELENGTH_H_INCLUDED
9
10/* Encode length by using 7bit per Byte :
11 * Most significant bit of each byte specifies that the
12 * following byte is part of the code */
13
14/* n : unsigned
15 * p : unsigned char *
16 */
17#define DECODELENGTH(n, p) n = 0; \
18 do { n = (n << 7) | (*p & 0x7f); } \
19 while((*(p++)&0x80) && (n<(1<<25)));
20
21/* n : unsigned
22 * READ : function/macro to read one byte (unsigned char)
23 */
24#define DECODELENGTH_READ(n, READ) \
25 n = 0; \
26 do { \
27 unsigned char c; \
28 READ(c); \
29 n = (n << 7) | (c & 0x07f); \
30 if(!(c&0x80)) break; \
31 } while(n<(1<<25));
32
33/* n : unsigned
34 * p : unsigned char *
35 * p_limit : unsigned char *
36 */
37#define DECODELENGTH_CHECKLIMIT(n, p, p_limit) \
38 n = 0; \
39 do { \
40 if((p) >= (p_limit)) break; \
41 n = (n << 7) | (*(p) & 0x7f); \
42 } while((*((p)++)&0x80) && (n<(1<<25)));
43
44
45/* n : unsigned
46 * p : unsigned char *
47 */
48#define CODELENGTH(n, p) if(n>=268435456) *(p++) = (n >> 28) | 0x80; \
49 if(n>=2097152) *(p++) = (n >> 21) | 0x80; \
50 if(n>=16384) *(p++) = (n >> 14) | 0x80; \
51 if(n>=128) *(p++) = (n >> 7) | 0x80; \
52 *(p++) = n & 0x7f;
53
54#endif /* CODELENGTH_H_INCLUDED */
55