utils: simplify/optimize escaping

utils.cpp

@@ -1,4 +1,4 @@
-/* Copyright (c) 2018 Albert S.
+/* Copyright (c) 2018-2020 Albert S.
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -27,28 +27,30 @@ SOFTWARE.
 #include "logger.h"
 #include "utils.h"
 
-// TODO: instead of returning vector maybe provide an iterator version too.
-
-// TODO: % may not be necessary (was in C version just to be sure against format string attacks
-// TODO: hopefully not too slow looking up every character here:
-const std::map<char, std::string> replacements = {{'<', "&lt;"}, {'>', "gt;"}, {'\"', "&quot;"}, {'%', "&#37;"}};
 std::string utils::html_xss(std::string_view str)
 {
 	std::string result;
-	int size = str.length();
-	for(int i = 0; i < size; i++)
+	for(char c : str)
 	{
-		char c = str[i];
-		auto val = replacements.find(c);
-		if(val != replacements.end())
-		{
-			result += val->second;
-		}
-		else
+		switch(c)
 		{
+		case '<':
+			result += "&lt;";
+			break;
+		case '>':
+			result += "&gt;";
+			break;
+		case '\"':
+			result += "&quot;";
+			break;
+		case '%':
+			result += "&#37;";
+			break;
+		default:
 			result += c;
 		}
 	}
+
 	return result;
 }
 
@@ -93,6 +95,7 @@ std::vector<std::string> utils::splitByString(const std::string &str, const std:
 {
 	return splitByRegex(str, delim + "+");
 }
+
 std::vector<std::string> utils::splitByRegex(const std::string &str, const std::string &regex)
 {
 	std::vector<std::string> result;