From 88f1ca95fd7509cc07b2e99f93cb149713f72134 Mon Sep 17 00:00:00 2001
From: BlackMATov <blackmat@mail.ru>
Date: Wed, 25 Nov 2020 23:10:52 +0700
Subject: [PATCH] std hash support

---
 headers/vmath.hpp/vmath_ext.hpp     | 10 ++++++++++
 headers/vmath.hpp/vmath_mat_ext.hpp | 10 ++++++++++
 headers/vmath.hpp/vmath_vec_ext.hpp | 10 ++++++++++
 untests/vmath_mat_ext_tests.cpp     |  5 +++++
 untests/vmath_vec_ext_tests.cpp     | 11 +++++++++++
 5 files changed, 46 insertions(+)

diff --git a/headers/vmath.hpp/vmath_ext.hpp b/headers/vmath.hpp/vmath_ext.hpp
index 1dd9b72..a5a0c02 100644
--- a/headers/vmath.hpp/vmath_ext.hpp
+++ b/headers/vmath.hpp/vmath_ext.hpp
@@ -10,6 +10,16 @@
 
 #include "vmath_fun.hpp"
 
+namespace vmath_hpp::detail
+{
+    struct hash_combiner {
+        template < typename T >
+        std::size_t operator()(std::size_t seed, const T& x) noexcept {
+            return (seed ^= std::hash<T>{}(x) + 0x9e3779b9 + (seed << 6) + ( seed >> 2));
+        }
+    };
+}
+
 namespace vmath_hpp
 {
     template < typename To, typename From >
diff --git a/headers/vmath.hpp/vmath_mat_ext.hpp b/headers/vmath.hpp/vmath_mat_ext.hpp
index 6639501..bf6494d 100644
--- a/headers/vmath.hpp/vmath_mat_ext.hpp
+++ b/headers/vmath.hpp/vmath_mat_ext.hpp
@@ -18,6 +18,16 @@
 #include "vmath_mat.hpp"
 #include "vmath_mat_fun.hpp"
 
+namespace std
+{
+    template < typename T, size_t Size >
+    struct hash<vmath_hpp::mat<T, Size>> {
+        size_t operator()(const vmath_hpp::mat<T, Size>& m) const noexcept {
+            return vmath_hpp::detail::fold(vmath_hpp::detail::hash_combiner{}, size_t{}, m);
+        }
+    };
+}
+
 namespace vmath_hpp
 {
     // cast_to
diff --git a/headers/vmath.hpp/vmath_vec_ext.hpp b/headers/vmath.hpp/vmath_vec_ext.hpp
index 84dd79d..75b3019 100644
--- a/headers/vmath.hpp/vmath_vec_ext.hpp
+++ b/headers/vmath.hpp/vmath_vec_ext.hpp
@@ -14,6 +14,16 @@
 #include "vmath_vec.hpp"
 #include "vmath_vec_fun.hpp"
 
+namespace std
+{
+    template < typename T, size_t Size >
+    struct hash<vmath_hpp::vec<T, Size>> {
+        size_t operator()(const vmath_hpp::vec<T, Size>& v) const noexcept {
+            return vmath_hpp::detail::fold(vmath_hpp::detail::hash_combiner{}, size_t{}, v);
+        }
+    };
+}
+
 namespace vmath_hpp
 {
     // cast_to
diff --git a/untests/vmath_mat_ext_tests.cpp b/untests/vmath_mat_ext_tests.cpp
index 342ffd3..9cceae5 100644
--- a/untests/vmath_mat_ext_tests.cpp
+++ b/untests/vmath_mat_ext_tests.cpp
@@ -18,6 +18,11 @@ namespace
 }
 
 TEST_CASE("vmath/mat_ext") {
+    SECTION("hash") {
+        REQUIRE(std::hash<mat2i>{}({1,2,3,4}) == std::hash<mat2i>{}({1,2,3,4}));
+        REQUIRE_FALSE(std::hash<mat2i>{}({1,2,3,4}) == std::hash<mat2i>{}({1,2,4,3}));
+    }
+
     SECTION("cast_to") {
         constexpr auto m = cast_to<int>(mat2f{1.5f});
         STATIC_REQUIRE(m == mat2i(1));
diff --git a/untests/vmath_vec_ext_tests.cpp b/untests/vmath_vec_ext_tests.cpp
index a013df2..0db5f33 100644
--- a/untests/vmath_vec_ext_tests.cpp
+++ b/untests/vmath_vec_ext_tests.cpp
@@ -18,6 +18,17 @@ namespace
 }
 
 TEST_CASE("vmath/vec_ext") {
+    SECTION("hash") {
+        REQUIRE(std::hash<vec2i>{}({1,2}) == std::hash<vec2i>{}({1,2}));
+        REQUIRE_FALSE(std::hash<vec2i>{}({1,2}) == std::hash<vec2i>{}({2,1}));
+
+        REQUIRE(std::hash<vec3i>{}({1,2,3}) == std::hash<vec3i>{}({1,2,3}));
+        REQUIRE_FALSE(std::hash<vec3i>{}({1,2,3}) == std::hash<vec3i>{}({3,2,1}));
+
+        REQUIRE(std::hash<vec4i>{}({1,2,3,4}) == std::hash<vec4i>{}({1,2,3,4}));
+        REQUIRE_FALSE(std::hash<vec4i>{}({1,2,3,4}) == std::hash<vec4i>{}({3,2,1,4}));
+    }
+
     SECTION("cast_to") {
         constexpr auto v = cast_to<int>(vec2f{1.5f});
         STATIC_REQUIRE(v == vec2i(1));