Initial data commit

Task/URL-decoding/C/url-decoding.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <string.h>
+
+inline int ishex(int x)
+{
+	return	(x >= '0' && x <= '9')	||
+		(x >= 'a' && x <= 'f')	||
+		(x >= 'A' && x <= 'F');
+}
+
+int decode(const char *s, char *dec)
+{
+	char *o;
+	const char *end = s + strlen(s);
+	int c;
+
+	for (o = dec; s <= end; o++) {
+		c = *s++;
+		if (c == '+') c = ' ';
+		else if (c == '%' && (	!ishex(*s++)	||
+					!ishex(*s++)	||
+					!sscanf(s - 2, "%2x", &c)))
+			return -1;
+
+		if (dec) *o = c;
+	}
+
+	return o - dec;
+}
+
+int main()
+{
+	const char *url = "http%3A%2F%2ffoo+bar%2fabcd";
+	char out[strlen(url) + 1];
+
+	printf("length: %d\n", decode(url, 0));
+	puts(decode(url, out) < 0 ? "bad string" : out);
+
+	return 0;
+}