pktgen/printhex.c

   1 /* prints hex string argv in binary to stdout */
   2
   3 #include <stdio.h>
   4 #include <ctype.h>
   5
   6 int char2hex(char c) {
   7         c = tolower((unsigned int)c);
   8         if (isdigit((unsigned int)c)) {
   9                 return c-'0';
  10         } else if (c >= 'a' && c <= 'f') {
  11                 return c-'a'+10;
  12         } else {
  13                 return -1;
  14         }
  15 }
  16
  17 void spew_bytes(const char *s) {
  18         char buf[256];
  19         int n1,n2;
  20         char *p;
  21 again:
  22         p = buf;
  23         while(p < (buf+sizeof(buf))) {
  24                 n1 = char2hex(*s++);
  25                 if(n1 < 0) break;
  26                 n2 = char2hex(*s++);
  27                 if(n2 < 0) break;
  28                 *p++ = (n1<<4) + n2;
  29         }
  30         if(p!=buf) write(1, buf, p-buf);
  31         if( (n1|n2)>=0 ) goto again;
  32 }
  33
  34 int main(int argc,char** argv) {
  35         while(--argc > 0)
  36                 spew_bytes(*++argv);
  37         return 0;
  38 }