release/src/router/miniupnpd/codelength.h

   1 /* $Id: codelength.h,v 1.5 2015/07/09 12:40:18 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 */