sys/src/libc/port/u16.c

   1 #include <u.h>
   2 #include <libc.h>
   3 static char t16e[] = "0123456789ABCDEF";
   4
   5 int
   6 dec16(uchar *out, int lim, char *in, int n)
   7 {
   8         int c, w = 0, i = 0;
   9         uchar *start = out;
  10         uchar *eout = out + lim;
  11
  12         while(n-- > 0){
  13                 c = *in++;
  14                 if('0' <= c && c <= '9')
  15                         c = c - '0';
  16                 else if('a' <= c && c <= 'z')
  17                         c = c - 'a' + 10;
  18                 else if('A' <= c && c <= 'Z')
  19                         c = c - 'A' + 10;
  20                 else
  21                         continue;
  22                 w = (w<<4) + c;
  23                 i++;
  24                 if(i == 2){
  25                         if(out + 1 > eout)
  26                                 goto exhausted;
  27                         *out++ = w;
  28                         w = 0;
  29                         i = 0;
  30                 }
  31         }
  32 exhausted:
  33         return out - start;
  34 }
  35
  36 int
  37 enc16(char *out, int lim, uchar *in, int n)
  38 {
  39         uint c;
  40         char *eout = out + lim;
  41         char *start = out;
  42
  43         while(n-- > 0){
  44                 c = *in++;
  45                 if(out + 2 >= eout)
  46                         goto exhausted;
  47                 *out++ = t16e[c>>4];
  48                 *out++ = t16e[c&0xf];
  49         }
  50 exhausted:
  51         *out = 0;
  52         return out - start;
  53 }