--- /dev/null
+'use strict';
+
+module.exports = locate;
+
+var PROTOCOLS = ['https://', 'http://', 'mailto:'];
+
+function locate(value, fromIndex) {
+ var length = PROTOCOLS.length;
+ var index = -1;
+ var min = -1;
+ var position;
+
+ if (!this.options.gfm) {
+ return -1;
+ }
+
+ while (++index < length) {
+ position = value.indexOf(PROTOCOLS[index], fromIndex);
+
+ if (position !== -1 && (position < min || min === -1)) {
+ min = position;
+ }
+ }
+
+ return min;
+}