mg_url_decode() moved to string.c

build/src/string.c

@@ -286,6 +286,31 @@ void mg_url_encode(const char *src, char *dst, size_t dst_len) {
   *dst = '\0';
 }
 
+int mg_url_decode(const char *src, int src_len, char *dst,
+                  int dst_len, int is_form_url_encoded) {
+  int i, j, a, b;
+#define HEXTOI(x) (isdigit(x) ? x - '0' : x - 'W')
+
+  for (i = j = 0; i < src_len && j < dst_len - 1; i++, j++) {
+    if (src[i] == '%' && i < src_len - 2 &&
+        isxdigit(* (const unsigned char *) (src + i + 1)) &&
+        isxdigit(* (const unsigned char *) (src + i + 2))) {
+      a = tolower(* (const unsigned char *) (src + i + 1));
+      b = tolower(* (const unsigned char *) (src + i + 2));
+      dst[j] = (char) ((HEXTOI(a) << 4) | HEXTOI(b));
+      i += 2;
+    } else if (is_form_url_encoded && src[i] == '+') {
+      dst[j] = ' ';
+    } else {
+      dst[j] = src[i];
+    }
+  }
+
+  dst[j] = '\0'; // Null-terminate the destination
+
+  return i >= src_len ? j : -1;
+}
+
 // Check whether full request is buffered. Return:
 //   -1  if request is malformed
 //    0  if request is not yet fully buffered