Created Utility.hpp and moved some code into this file. Also improved parse_query_string.

utility.hpp

@@ -0,0 +1,103 @@
+#ifndef SIMPLE_WEB_SERVER_UTILITY_HPP
+#define SIMPLE_WEB_SERVER_UTILITY_HPP
+
+#include <string>
+#include <unordered_map>
+
+// TODO when switching to c++14, use [[deprecated]] instead
+#ifndef DEPRECATED
+#ifdef __GNUC__
+#define DEPRECATED __attribute__((deprecated))
+#elif defined(_MSC_VER)
+#define DEPRECATED __declspec(deprecated)
+#else
+#define DEPRECATED
+#endif
+#endif
+
+namespace SimpleWeb {
+#ifndef CASE_INSENSITIVE_EQUAL_AND_HASH
+#define CASE_INSENSITIVE_EQUAL_AND_HASH
+inline bool case_insensitive_equal(const std::string &str1, const std::string &str2) {
+  return str1.size() == str2.size() &&
+         std::equal(str1.begin(), str1.end(), str2.begin(), [](char a, char b) {
+           return tolower(a) == tolower(b);
+         });
+}
+class CaseInsensitiveEqual {
+public:
+  bool operator()(const std::string &str1, const std::string &str2) const {
+    return case_insensitive_equal(str1, str2);
+  }
+};
+// Based on https://stackoverflow.com/questions/2590677/how-do-i-combine-hash-values-in-c0x/2595226#2595226
+class CaseInsensitiveHash {
+public:
+  size_t operator()(const std::string &str) const {
+    size_t h = 0;
+    std::hash<int> hash;
+    for(auto c : str)
+      h ^= hash(tolower(c)) + 0x9e3779b9 + (h << 6) + (h >> 2);
+    return h;
+  }
+};
+#endif
+
+typedef std::unordered_multimap<std::string, std::string, CaseInsensitiveHash, CaseInsensitiveEqual> CaseInsensitiveMultimap;
+
+/// Percent encoding and decoding
+class Percent {
+public:
+  static std::string decode(const std::string &value) {
+    std::string result;
+
+    for(size_t i = 0; i < value.size(); ++i) {
+      auto &chr = value[i];
+      if(chr == '%' && i + 2 < value.size()) {
+        auto hex = value.substr(i + 1, 2);
+        auto decoded_chr = static_cast<char>(std::strtol(hex.c_str(), nullptr, 16));
+        result += decoded_chr;
+        i += 2;
+      }
+      else if(chr == '+')
+        result += ' ';
+      else
+        result += chr;
+    }
+
+    return result;
+  }
+};
+
+/// Returns query keys with percent-decoded values.
+inline CaseInsensitiveMultimap parse_query_string(const std::string &query_string) {
+  CaseInsensitiveMultimap result;
+
+  if(query_string.empty())
+    return result;
+
+  size_t parameter_pos = 0;
+  size_t parameter_end_pos = -1;
+  size_t value_pos = -1;
+  for(size_t c = 0; c < query_string.size() + 1; ++c) {
+    if(query_string[c] == '&' || c == query_string.size()) {
+      auto parameter = query_string.substr(parameter_pos, (parameter_end_pos == static_cast<size_t>(-1) ? c : parameter_end_pos) - parameter_pos);
+      if(!parameter.empty()) {
+        auto value = value_pos == static_cast<size_t>(-1) ? std::string() : query_string.substr(value_pos, c - value_pos);
+        result.emplace(std::move(parameter), Percent::decode(value));
+      }
+      parameter_pos = c + 1;
+      parameter_end_pos = -1;
+      value_pos = -1;
+    }
+    else if(query_string[c] == '=') {
+      parameter_end_pos = c;
+      value_pos = c + 1;
+    }
+  }
+
+  return result;
+}
+} // namespace SimpleWeb
+
+#endif // SIMPLE_WEB_SERVER_UTILITY_HPP