Added support for NMEA files

src/misc.cpp

@@ -1,4 +1,5 @@
 #include <cmath>
+#include <cctype>
 #include "misc.h"
 
 
@@ -33,3 +34,17 @@ double niceNum(double x, int round)
 
 	return nf * pow(10.0, expv);
 }
+
+int str2int(const char *str, int len)
+{
+	int res = 0;
+
+	for (const char *sp = str; sp < str + len; sp++) {
+		if (::isdigit(*sp))
+			res = res * 10 + *sp - '0';
+		else
+			return -1;
+	}
+
+	return res;
+}