From 714d9fe433341783a381da442c7073bc87a401e3 Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Sun, 7 Aug 2022 10:23:09 -0500
Subject: [PATCH] [ox/std] Add support for integral types as keys in HashMap

---
 deps/ox/src/ox/std/hashmap.hpp    | 30 +++++++++++++++++++++---------
 deps/ox/src/ox/std/test/tests.cpp | 15 ++++++++++-----
 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/deps/ox/src/ox/std/hashmap.hpp b/deps/ox/src/ox/std/hashmap.hpp
index 1b7c1877..469f0efe 100644
--- a/deps/ox/src/ox/std/hashmap.hpp
+++ b/deps/ox/src/ox/std/hashmap.hpp
@@ -76,7 +76,7 @@ class HashMap {
 		/**
 		 * K is assumed to be a null terminated string.
 		 */
-		constexpr static uint64_t hash(K, int len = 0xFFFF) noexcept;
+		constexpr static uint64_t hash(auto) noexcept;
 
 		/**
 		 * K is assumed to be a null terminated string.
@@ -182,16 +182,13 @@ constexpr void HashMap<K, T>::erase(const K &k) {
 		return;
 	}
 	auto h = hash(k) % m_pairs.size();
-	char hashStr[sizeof(h) + 1];
-	ox_memcpy(hashStr, &h, sizeof(h));
-	hashStr[sizeof(h)] = 0;
 	while (true) {
 		const auto &p = m_pairs[h];
 		if (p == nullptr || ox_strcmp(p->key, k) == 0) {
 			oxIgnoreError(m_pairs.erase(h));
 			break;
 		} else {
-			h = hash(hashStr, 8) % m_pairs.size();
+			h = hash(h) % m_pairs.size();
 		}
 	}
 	oxIgnoreError(m_keys.erase(ox::find(m_keys.begin(), m_keys.end(), k)));
@@ -232,10 +229,18 @@ constexpr void HashMap<K, T>::expand() {
 }
 
 template<typename K, typename T>
-constexpr uint64_t HashMap<K, T>::hash(K k, int len) noexcept {
+constexpr uint64_t HashMap<K, T>::hash(auto k) noexcept {
 	uint64_t sum = 1;
-	for (auto i = 0u; i < static_cast<uint64_t>(len) && k[i]; ++i) {
-		sum += ((sum + static_cast<uint64_t>(k[i])) * 7) * sum;
+	if constexpr(is_integral_v<decltype(k)>) {
+		for (auto i = 0u; i < sizeof(K); ++i) {
+			const auto shift = i * 8;
+			const auto v = static_cast<uint64_t>(k >> shift & 0xff);
+			sum += (sum + v) * 7 * sum;
+		}
+	} else {
+		for (auto i = 0u; k[i]; ++i) {
+			sum += ((sum + static_cast<uint64_t>(k[i])) * 7) * sum;
+		}
 	}
 	return sum;
 }
@@ -258,7 +263,14 @@ constexpr typename HashMap<K, T>::Pair *&HashMap<K, T>::access(Vector<Pair*> &pa
 	auto h = hash(k) % pairs.size();
 	while (true) {
 		auto &p = pairs[h];
-		if (p == nullptr || ox_strcmp(p->key, k) == 0) {
+		bool matches = [&] {
+			if constexpr (is_integral_v<K>) {
+				return p == nullptr || k == p->key;
+			} else {
+				return p == nullptr || ox_strcmp(p->key, k) == 0;
+			}
+		}();
+		if (matches) {
 			return p;
 		} else {
 			h = (h + 1) % pairs.size();
diff --git a/deps/ox/src/ox/std/test/tests.cpp b/deps/ox/src/ox/std/test/tests.cpp
index e2d17843..952e38b1 100644
--- a/deps/ox/src/ox/std/test/tests.cpp
+++ b/deps/ox/src/ox/std/test/tests.cpp
@@ -109,11 +109,16 @@ std::map<ox::String, ox::Error(*)()> tests = {
 	{
 		"HashMap",
 		[] {
-			ox::HashMap<const char*, int> v;
-			v["asdf"] = 42;
-			v["aoeu"] = 100;
-			oxAssert(v["asdf"] == 42, "asdf != 42");
-			oxAssert(v["aoeu"] == 100, "aoeu != 100");
+			ox::HashMap<const char*, int> si;
+			si["asdf"] = 42;
+			si["aoeu"] = 100;
+			oxAssert(si["asdf"] == 42, "asdf != 42");
+			oxAssert(si["aoeu"] == 100, "aoeu != 100");
+			ox::HashMap<int, int> ii;
+			ii[4] = 42;
+			ii[5] = 100;
+			oxAssert(ii[4] == 42, "4 != 42");
+			oxAssert(ii[5] == 100, "5 != 100");
 			return OxError(0);
 		}
 	},