From f8ecebef8c37df786bc434ba270948cb18154aab Mon Sep 17 00:00:00 2001
From: Deukhoofd <deukhoofd@gmail.com>
Date: Thu, 27 Feb 2020 13:42:26 +0100
Subject: [PATCH] Support for using ConstString in unordered_maps and switch
 case statements.

---
 src/ConstString.hpp        | 27 ++++++++++++++++++++++++++-
 tests/ConstStringTests.cpp | 26 ++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 tests/ConstStringTests.cpp

diff --git a/src/ConstString.hpp b/src/ConstString.hpp
index 68c415b..423affc 100644
--- a/src/ConstString.hpp
+++ b/src/ConstString.hpp
@@ -5,6 +5,7 @@
 #include <cstdint>
 #include <cstring>
 #include <string>
+
 namespace Arbutils {
     class ConstString {
     private:
@@ -18,7 +19,9 @@ namespace Arbutils {
         inline static int constexpr Length(const char* str) { return *str ? 1 + Length(str + 1) : 0; }
 
     public:
+        constexpr ConstString() : _str(""), _length(0), _hash(Hash("")){};
         constexpr explicit ConstString(const char* str) : _str(str), _length(Length(str)), _hash(Hash(str)){};
+        constexpr explicit ConstString(const char* str, size_t size) : _str(str), _length(size), _hash(Hash(str)){};
 
         [[nodiscard]] inline constexpr const char* c_str() const noexcept { return _str; }
         [[nodiscard]] inline std::string std_str() const { return std::string(_str, _length); }
@@ -26,8 +29,30 @@ namespace Arbutils {
         [[nodiscard]] inline constexpr size_t Length() const noexcept { return _length; }
 
         [[nodiscard]] inline constexpr uint32_t GetHash() const noexcept { return _hash; }
+
+        constexpr std::size_t operator()(ConstString const& s) const noexcept { return s.GetHash(); }
+        inline constexpr operator uint32_t() const{ return _hash; }
+
+        inline constexpr bool operator==(const ConstString& rhs) const{
+            return _hash == rhs._hash;
+        }
+        inline constexpr bool operator!=(const ConstString& rhs) const{
+            return _hash != rhs._hash;
+        }
+    };
+}
+
+inline constexpr Arbutils::ConstString operator"" _const(const char* c, unsigned long l) {
+    return Arbutils::ConstString(c, l);
+}
+inline constexpr Arbutils::ConstString operator"" _c(const char* c, unsigned long l) {
+    return Arbutils::ConstString(c, l);
+}
+
+namespace std {
+    template <> struct hash<Arbutils::ConstString> {
+        constexpr std::size_t operator()(Arbutils::ConstString const& s) const noexcept { return s.GetHash(); }
     };
-    inline constexpr ConstString operator"" _const(const char* c) { return ConstString(c); }
 }
 
 #endif // ARBUTILS_CONSTSTRING_HPP
diff --git a/tests/ConstStringTests.cpp b/tests/ConstStringTests.cpp
new file mode 100644
index 0000000..7ed588a
--- /dev/null
+++ b/tests/ConstStringTests.cpp
@@ -0,0 +1,26 @@
+#ifdef TESTS_BUILD
+#include <cstring>
+#include <unordered_map>
+#include "../extern/catch.hpp"
+#include "../src/ConstString.hpp"
+
+TEST_CASE("Use const string in unordered_map", "[Utilities]") {
+    std::unordered_map<Arbutils::ConstString, int32_t> map;
+    map.insert({"foo"_c, 1});
+    map.insert({"bar"_c, 5});
+
+    CHECK(map["bar"_c] == 5);
+    CHECK(map["foo"_c] == 1);
+}
+
+TEST_CASE("Use const string in switch case", "[Utilities]") {
+    auto val = Arbutils::ConstString("foobar");
+    switch (val){
+        case "foo"_c: FAIL(); break;
+        case "bar"_c: FAIL(); break;
+        case "foobar"_c: SUCCEED(); break;
+        default: FAIL(); break;
+    }
+}
+
+#endif
\ No newline at end of file