apcgi

Web client for aps on trusted networks
git clone git://jacobedwards.org/apcgi
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urldecode.c (655B)

      1 /*
      2  * Copyright 2021 Jacob R. Edwards
      3  * Decode URI Percent Encoding (See RFC 2396, Section 2.4.1., "Escaped Encoding")
      4  */
      5 
      6 #include <stdio.h>
      7 #include <stdlib.h>
      8 
      9 int
     10 main(void)
     11 {
     12 	char *b;
     13 	size_t l;
     14 	size_t s;
     15 	char o[3];
     16 	int p;
     17 	unsigned char c;
     18 	char *e;
     19 
     20 	o[2] = 0;
     21 	b = NULL;
     22 	s = 0;
     23 	while ((l = getdelim(&b, &s, '%', stdin)) != -1) {
     24 		if (b[l - 1] == '%') {
     25 			--l;
     26 			if (fread(o, 1, 2, stdin) != 2)
     27 				goto badescape;
     28 			c = strtoul(o, &e, 16);
     29 			if (*e) {
     30 badescape:
     31 				perror("bad escape");
     32 				return 1;
     33 			}
     34 			p = 1;
     35 		} else
     36 			p = 0;
     37 		if (fwrite(b, 1, l, stdout) != l || (p && fputc(c, stdout) < 0))
     38 			return 1;
     39 	}
     40 
     41 	return 0;
     42 }