From 4f86cd9f083e46e3fba0130cd63867ef7a37d763 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sat, 17 Jun 2023 00:07:43 +0200
Subject: [PATCH] libluna: Add a so very basic HashMap

---
 libluna/include/luna/HashMap.h  | 42 +++++++++++++++++++++++++++++++++
 tests/libluna/TestHashTable.cpp | 15 ++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 libluna/include/luna/HashMap.h

diff --git a/libluna/include/luna/HashMap.h b/libluna/include/luna/HashMap.h
new file mode 100644
index 00000000..ba149304
--- /dev/null
+++ b/libluna/include/luna/HashMap.h
@@ -0,0 +1,42 @@
+#pragma once
+#include <luna/HashTable.h>
+
+template <typename K, typename V> struct HashPair
+{
+    K key;
+    Option<V> value;
+
+    bool operator==(const HashPair<K, V>& other) const
+    {
+        return key == other.key;
+    }
+};
+
+template <typename K, typename V> u64 hash(const HashPair<K, V>& value, u64 salt)
+{
+    return hash(value.key, salt);
+}
+
+template <typename K, typename V> struct HashMap
+{
+  public:
+    Result<bool> try_set(const K& key, const V& value)
+    {
+        return m_table.try_set(HashPair<K, V> { key, value });
+    }
+
+    Option<V> try_get(const K& key)
+    {
+        auto* p = m_table.try_find(HashPair<K, V> { key, {} });
+        if (!p) return {};
+        return p->value;
+    }
+
+    bool try_remove(const K& key)
+    {
+        return m_table.try_remove(HashPair<K, V> { key, {} });
+    }
+
+  private:
+    HashTable<HashPair<K, V>> m_table;
+};
diff --git a/tests/libluna/TestHashTable.cpp b/tests/libluna/TestHashTable.cpp
index 27f56d28..5b410a24 100644
--- a/tests/libluna/TestHashTable.cpp
+++ b/tests/libluna/TestHashTable.cpp
@@ -1,3 +1,4 @@
+#include <luna/HashMap.h>
 #include <luna/HashTable.h>
 #include <os/File.h>
 #include <test.h>
@@ -66,6 +67,19 @@ TestResult test_hash_table_duplicates()
     test_success;
 }
 
+TestResult test_hash_map_set_and_get()
+{
+    HashMap<int, int> map;
+
+    validate(TRY(map.try_set(1, 42)));
+
+    validate(map.try_get(1).release_value() == 42);
+
+    validate(!map.try_get(6).has_value());
+
+    test_success;
+}
+
 Result<void> test_main()
 {
     test_prelude;
@@ -74,6 +88,7 @@ Result<void> test_main()
     run_test(test_hash_table_find);
     run_test(test_hash_table_remove);
     run_test(test_hash_table_duplicates);
+    run_test(test_hash_map_set_and_get);
 
     return {};
 }