1 /*
2  *	upas/unesc - interpret =?foo?bar?=char?= escapes
3  */
4 
5 #include <stdio.h>
6 #include <stdlib.h>
7 
8 int
9 hex(int c)
10 {
11 	if('0' <= c && c <= '9')
12 		return c - '0';
13 	if('A' <= c && c <= 'F')
14 		return c - 'A' + 10;
15 	if('a' <= c && c <= 'f')
16 		return c - 'a' + 10;
17 	return 0;
18 }
19 
20 int
21 main(int argc, char **argv)
22 {
23 	int c;
24 
25 	while((c=getchar()) != EOF){
26 		if(c == '='){
27 			if((c=getchar()) == '?'){
28 				while((c=getchar()) != EOF && c != '?')
29 					continue;
30 				while((c=getchar()) != EOF && c != '?')
31 					continue;
32 				while((c=getchar()) != EOF && c != '?'){
33 					if(c == '='){
34 						c = hex(getchar()) << 4;
35 						c |= hex(getchar());
36 					}
37 					putchar(c);
38 				}
39 				(void) getchar();	/* consume '=' */
40 			}else{
41 				putchar('=');
42 				putchar(c);
43 			}
44 		}else
45 			putchar(c);
46 	}
47 	exit(0);
48 }