Implement dumb `PtrMap`

1 files changed, 209 insertions, 238 deletions

diff --git a/src/ptr_map.cpp b/src/ptr_map.cpp
index 23278014f..8fd627768 100644
--- a/src/ptr_map.cpp
+++ b/src/ptr_map.cpp
@@ -16,23 +16,21 @@ struct MapFindResult {
 };
 
 enum : MapIndex { MAP_SENTINEL = ~(MapIndex)0 };
+static void *const MAP_TOMBSTONE = (void *)~(uintptr)0;
 
 template <typename K, typename V>
 struct PtrMapEntry {
 	static_assert(sizeof(K) == sizeof(void *), "Key size must be pointer size");
 	
-	K        key;
-	V        value;
-	MapIndex next;
+	K key;
+	V value;
 };
 
 template <typename K, typename V>
 struct PtrMap {
-	MapIndex *         hashes;
-	usize              hashes_count;
 	PtrMapEntry<K, V> *entries;
 	u32                count;
-	u32                entries_capacity;
+	u32                capacity;
 };
 
 
@@ -69,7 +67,6 @@ template <typename K, typename V> gb_internal void map_grow             (PtrMap<
 template <typename K, typename V> gb_internal void map_rehash           (PtrMap<K, V> *h, isize new_count);
 template <typename K, typename V> gb_internal void map_reserve          (PtrMap<K, V> *h, isize cap);
 
-#if PTR_MAP_ENABLE_MULTI_MAP
 // Mutlivalued map procedure
 template <typename K, typename V> gb_internal PtrMapEntry<K, V> * multi_map_find_first(PtrMap<K, V> *h, K key);
 template <typename K, typename V> gb_internal PtrMapEntry<K, V> * multi_map_find_next (PtrMap<K, V> *h, PtrMapEntry<K, V> *e);
@@ -79,7 +76,6 @@ template <typename K, typename V> gb_internal void  multi_map_get_all   (PtrMap<
 template <typename K, typename V> gb_internal void  multi_map_insert    (PtrMap<K, V> *h, K key, V const &value);
 template <typename K, typename V> gb_internal void  multi_map_remove    (PtrMap<K, V> *h, K key, PtrMapEntry<K, V> *e);
 template <typename K, typename V> gb_internal void  multi_map_remove_all(PtrMap<K, V> *h, K key);
-#endif
 
 gb_internal gbAllocator map_allocator(void) {
 	return heap_allocator();
@@ -94,170 +90,141 @@ gb_internal gb_inline void map_init(PtrMap<K, V> *h, isize capacity) {
 template <typename K, typename V>
 gb_internal gb_inline void map_destroy(PtrMap<K, V> *h) {
 	gbAllocator a = map_allocator();
-	gb_free(a, h->hashes);
 	gb_free(a, h->entries);
 }
 
-template <typename K, typename V>
-gb_internal void map__resize_hashes(PtrMap<K, V> *h, usize count) {
-	h->hashes_count = cast(u32)resize_array_raw(&h->hashes, map_allocator(), h->hashes_count, count, MAP_CACHE_LINE_SIZE);
-}
-
-template <typename K, typename V>
-gb_internal void map__reserve_entries(PtrMap<K, V> *h, usize capacity) {
-	h->entries_capacity = cast(u32)resize_array_raw(&h->entries, map_allocator(), h->entries_capacity, capacity, MAP_CACHE_LINE_SIZE);
-}
-
 
 template <typename K, typename V>
-gb_internal MapIndex map__add_entry(PtrMap<K, V> *h, K key) {
-	PtrMapEntry<K, V> e = {};
-	e.key = key;
-	e.next = MAP_SENTINEL;
-	if (h->count+1 >= h->entries_capacity) {
-		map__reserve_entries(h, gb_max(h->entries_capacity*2, 4));
-	}
-	h->entries[h->count++] = e;
-	return cast(MapIndex)(h->count-1);
-}
-
-template <typename K, typename V>
-gb_internal MapFindResult map__find(PtrMap<K, V> *h, K key) {
-	MapFindResult fr = {MAP_SENTINEL, MAP_SENTINEL, MAP_SENTINEL};
-	if (h->hashes_count == 0) {
-		return fr;
+gb_internal void map__insert(PtrMap<K, V> *h, K key, V const &value) {
+	if (h->count+1 >= h->capacity) {
+		map_grow(h);
 	}
 	u32 hash = ptr_map_hash_key(key);
-	fr.hash_index = cast(MapIndex)(hash & (h->hashes_count-1));
-	fr.entry_index = h->hashes[fr.hash_index];
-	while (fr.entry_index != MAP_SENTINEL) {
-		auto *entry = &h->entries[fr.entry_index];
-		if (entry->key == key) {
-			return fr;
+	u32 mask = h->capacity-1;
+	MapIndex index = hash & mask;
+	MapIndex original_index = index;
+	do {
+		auto *entry = h->entries+index;
+		if (!entry->key || entry->key == cast(K)MAP_TOMBSTONE) {
+			entry->key   = key;
+			entry->value = value;
+			h->count += 1;
+			return;
 		}
-		fr.entry_prev = fr.entry_index;
-		fr.entry_index = entry->next;
-	}
-	return fr;
-}
+		index = (index+1)&mask;
+	} while (index != original_index);
 
-template <typename K, typename V>
-gb_internal MapFindResult map__find_from_entry(PtrMap<K, V> *h, PtrMapEntry<K, V> *e) {
-	MapFindResult fr = {MAP_SENTINEL, MAP_SENTINEL, MAP_SENTINEL};
-	if (h->hashes_count == 0) {
-		return fr;
-	}
-	u32 hash = ptr_map_hash_key(e->key);
-	fr.hash_index  = cast(MapIndex)(hash & (h->hashes_count-1));
-	fr.entry_index = h->hashes[fr.hash_index];
-	while (fr.entry_index != MAP_SENTINEL) {
-		if (&h->entries[fr.entry_index] == e) {
-			return fr;
-		}
-		fr.entry_prev = fr.entry_index;
-		fr.entry_index = h->entries[fr.entry_index].next;
-	}
-	return fr;
+	GB_PANIC("FAILED TO INSERT");
 }
 
 template <typename K, typename V>
 gb_internal b32 map__full(PtrMap<K, V> *h) {
-	return 0.75f * h->hashes_count <= h->count;
+	return 0.75f * h->capacity <= h->count;
 }
 
 template <typename K, typename V>
 gb_internal gb_inline void map_grow(PtrMap<K, V> *h) {
-	isize new_count = gb_max(h->hashes_count<<1, 16);
-	map_rehash(h, new_count);
+	isize new_capacity = gb_max(h->capacity<<1, 16);
+	map_reserve(h, new_capacity);
 }
 
 template <typename K, typename V>
-gb_internal void map_reset_entries(PtrMap<K, V> *h) {
-	for (usize i = 0; i < h->hashes_count; i++) {
-		h->hashes[i] = MAP_SENTINEL;
-	}
-	for (usize i = 0; i < h->count; i++) {
-		MapFindResult fr;
-		PtrMapEntry<K, V> *e = &h->entries[i];
-		e->next = MAP_SENTINEL;
-		fr = map__find_from_entry(h, e);
-		if (fr.entry_prev == MAP_SENTINEL) {
-			h->hashes[fr.hash_index] = cast(MapIndex)i;
-		} else {
-			h->entries[fr.entry_prev].next = cast(MapIndex)i;
-		}
+gb_internal void try_map_grow(PtrMap<K, V> *h) {
+	if (h->capacity == 0 || map__full(h)) {
+		map_grow(h);
 	}
 }
 
+
 template <typename K, typename V>
 gb_internal void map_reserve(PtrMap<K, V> *h, isize cap) {
-	if (h->count*2 < h->hashes_count) {
+	if (cap < h->capacity) {
 		return;
 	}
-	map__reserve_entries(h, cap);
-	map__resize_hashes(h, cap*2);
-	map_reset_entries(h);
-}
+	cap = next_pow2_isize(cap);
+	typedef PtrMapEntry<K, V> EntryType;
 
+	PtrMap<K, V> new_h = {};
+	new_h.count    = 0;
+	new_h.capacity = cast(u32)cap;
+	new_h.entries = gb_alloc_array(string_map_allocator(), EntryType, new_h.capacity);
 
-template <typename K, typename V>
-gb_internal void map_rehash(PtrMap<K, V> *h, isize new_count) {
-	map_reserve(h, new_count);
+	if (h->count) {
+		for (u32 i = 0; i < h->capacity; i++) {
+			auto *entry = h->entries+i;
+			if (entry->key &&
+			    entry->key != cast(K)MAP_TOMBSTONE) {
+				map__insert(&new_h, entry->key, entry->value);
+			}
+		}
+	}
+	map_destroy(h);
+	*h = new_h;
 }
 
 template <typename K, typename V>
 gb_internal V *map_get(PtrMap<K, V> *h, K key) {
-	MapIndex hash_index  = MAP_SENTINEL;
-	MapIndex entry_prev  = MAP_SENTINEL;
-	MapIndex entry_index = MAP_SENTINEL;
-	if (h->hashes_count != 0) {
-		u32 hash = ptr_map_hash_key(key);
-		hash_index = cast(MapIndex)(hash & (h->hashes_count-1));
-		entry_index = h->hashes[hash_index];
-		while (entry_index != MAP_SENTINEL) {
-			auto *entry = &h->entries[entry_index];
-			if (entry->key == key) {
-				return &entry->value;
-			}
-			entry_prev = entry_index;
-			entry_index = entry->next;
-		}
+	if (h->count == 0) {
+		return nullptr;
+	}
+	if (key == 0) {
+		GB_PANIC("0 key");
 	}
+
+	u32 hash = ptr_map_hash_key(key);
+	u32 mask = (h->capacity-1);
+	u32 index = hash & mask;
+	u32 original_index = index;
+	do {
+		auto *entry = h->entries+index;
+		if (!entry->key) {
+			// NOTE(bill): no found, but there isn't any key removal for this hash map
+			return nullptr;
+		} else if (entry->key == key) {
+			return &entry->value;
+		}
+		index = (index+1) & mask;
+	} while (original_index != index);
 	return nullptr;
 }
 template <typename K, typename V>
-gb_internal V *map_try_get(PtrMap<K, V> *h, K key, MapFindResult *fr_) {
-	MapFindResult fr = {MAP_SENTINEL, MAP_SENTINEL, MAP_SENTINEL};
-	if (h->hashes_count != 0) {
-		u32 hash = ptr_map_hash_key(key);
-		fr.hash_index = cast(MapIndex)(hash & (h->hashes_count-1));
-		fr.entry_index = h->hashes[fr.hash_index];
-		while (fr.entry_index != MAP_SENTINEL) {
-			auto *entry = &h->entries[fr.entry_index];
-			if (entry->key == key) {
-				return &entry->value;
-			}
-			fr.entry_prev = fr.entry_index;
-			fr.entry_index = entry->next;
-		}
+gb_internal V *map_try_get(PtrMap<K, V> *h, K key, MapIndex *found_index_) {
+	if (found_index_) *found_index_ = ~(MapIndex)0;
+
+	if (h->count == 0) {
+		return nullptr;
 	}
-	if (h->hashes_count == 0 || map__full(h)) {
-		map_grow(h);
+	if (key == 0) {
+		GB_PANIC("0 key");
 	}
-	if (fr_) *fr_ = fr;
+
+	u32 hash = ptr_map_hash_key(key);
+	u32 mask = (h->capacity-1);
+	u32 index = hash & mask;
+	u32 original_index = index;
+	do {
+		auto *entry = h->entries+index;
+		if (!entry->key) {
+			// NOTE(bill): no found, but there isn't any key removal for this hash map
+			return nullptr;
+		} else if (entry->key == key) {
+			if (found_index_) *found_index_ = index;
+			return &entry->value;
+		}
+		index = (index+1) & mask;
+	} while (original_index != index);
 	return nullptr;
 }
 
 
 template <typename K, typename V>
-gb_internal void map_set_internal_from_try_get(PtrMap<K, V> *h, K key, V const &value, MapFindResult const &fr) {
-	MapIndex index = map__add_entry(h, key);
-	if (fr.entry_prev != MAP_SENTINEL) {
-		h->entries[fr.entry_prev].next = index;
+gb_internal void map_set_internal_from_try_get(PtrMap<K, V> *h, K key, V const &value, MapIndex found_index) {
+	if (found_index != MAP_SENTINEL) {
+		GB_ASSERT(h->entries[found_index].key == key);
+		h->entries[found_index].value = value;
 	} else {
-		h->hashes[fr.hash_index] = index;
+		map_set(h, key, value);
 	}
-	h->entries[index].value = value;
 }
 
 template <typename K, typename V>
@@ -269,116 +236,83 @@ gb_internal V &map_must_get(PtrMap<K, V> *h, K key) {
 
 template <typename K, typename V>
 gb_internal void map_set(PtrMap<K, V> *h, K key, V const &value) {
-	MapIndex index;
-	MapFindResult fr;
-	if (h->hashes_count == 0) {
-		map_grow(h);
-	}
-	fr = map__find(h, key);
-	if (fr.entry_index != MAP_SENTINEL) {
-		index = fr.entry_index;
-	} else {
-		index = map__add_entry(h, key);
-		if (fr.entry_prev != MAP_SENTINEL) {
-			h->entries[fr.entry_prev].next = index;
-		} else {
-			h->hashes[fr.hash_index] = index;
-		}
-	}
-	h->entries[index].value = value;
-
-	if (map__full(h)) {
-		map_grow(h);
+	GB_ASSERT(key != 0);
+	try_map_grow(h);
+	auto *found = map_get(h, key);
+	if (found) {
+		*found = value;
+		return;
 	}
+	map__insert(h, key, value);
 }
 
 // returns true if it previously existed
 template <typename K, typename V>
 gb_internal bool map_set_if_not_previously_exists(PtrMap<K, V> *h, K key, V const &value) {
-	MapIndex index;
-	MapFindResult fr;
-	if (h->hashes_count == 0) {
-		map_grow(h);
-	}
-	fr = map__find(h, key);
-	if (fr.entry_index != MAP_SENTINEL) {
+	try_map_grow(h);
+	auto *found = map_get(h, key);
+	if (found) {
 		return true;
-	} else {
-		index = map__add_entry(h, key);
-		if (fr.entry_prev != MAP_SENTINEL) {
-			h->entries[fr.entry_prev].next = index;
-		} else {
-			h->hashes[fr.hash_index] = index;
-		}
-	}
-	h->entries[index].value = value;
-
-	if (map__full(h)) {
-		map_grow(h);
 	}
+	map__insert(h, key, value);
 	return false;
 }
 
 
 template <typename K, typename V>
-gb_internal void map__erase(PtrMap<K, V> *h, MapFindResult const &fr) {
-	MapFindResult last;
-	if (fr.entry_prev == MAP_SENTINEL) {
-		h->hashes[fr.hash_index] = h->entries[fr.entry_index].next;
-	} else {
-		h->entries[fr.entry_prev].next = h->entries[fr.entry_index].next;
-	}
-	if (fr.entry_index == h->count-1) {
-		h->count--;
-		return;
-	}
-	h->entries[fr.entry_index] = h->entries[h->count-1];
-	h->count--;
-	
-	last = map__find(h, h->entries[fr.entry_index].key);
-	if (last.entry_prev != MAP_SENTINEL) {
-		h->entries[last.entry_prev].next = fr.entry_index;
-	} else {
-		h->hashes[last.hash_index] = fr.entry_index;
-	}
-}
-
-template <typename K, typename V>
 gb_internal void map_remove(PtrMap<K, V> *h, K key) {
-	MapFindResult fr = map__find(h, key);
-	if (fr.entry_index != MAP_SENTINEL) {
-		map__erase(h, fr);
+	MapIndex found_index = 0;
+	if (map_try_get(h, key, &found_index)) {
+		h->entries[found_index].key = cast(K)MAP_TOMBSTONE;
+		h->count -= 1;
 	}
 }
 
 template <typename K, typename V>
 gb_internal gb_inline void map_clear(PtrMap<K, V> *h) {
 	h->count = 0;
-	for (usize i = 0; i < h->hashes_count; i++) {
-		h->hashes[i] = MAP_SENTINEL;
-	}
+	gb_zero_array(h->entries, h->capacity);
 }
 
 
 #if PTR_MAP_ENABLE_MULTI_MAP
 template <typename K, typename V>
 gb_internal PtrMapEntry<K, V> *multi_map_find_first(PtrMap<K, V> *h, K key) {
-	MapIndex i = map__find(h, key).entry_index;
-	if (i == MAP_SENTINEL) {
+	if (h->count == 0) {
 		return nullptr;
 	}
-	return &h->entries[i];
+	u32 hash = ptr_map_hash_key(key);
+	u32 mask = (h->capacity-1);
+	u32 index = hash & mask;
+	u32 original_index = index;
+	do {
+		auto *entry = h->entries+index;
+		if (!entry->key) {
+			// NOTE(bill): no found, but there isn't any key removal for this hash map
+			return nullptr;
+		} else if (entry->key == key) {
+			return entry;
+		}
+		index = (index+1) & mask;
+	} while (original_index != index);
+	return nullptr;
 }
 
 template <typename K, typename V>
 gb_internal PtrMapEntry<K, V> *multi_map_find_next(PtrMap<K, V> *h, PtrMapEntry<K, V> *e) {
-	MapIndex i = e->next;
-	while (i != MAP_SENTINEL) {
-		if (h->entries[i].key == e->key) {
-			return &h->entries[i];
+	u32 mask = h->capacity-1;
+	MapIndex index = cast(MapIndex)(e - h->entries);
+	MapIndex original_index = index;
+	do {
+		index = (index+1)&mask;
+		auto *entry = h->entries+index;
+		if (!entry->key) {
+			return nullptr;
 		}
-		i = h->entries[i].next;
-	}
+		if (entry->key == e->key) {
+			return entry;
+		}
+	} while (original_index != index);
 	return nullptr;
 }
 
@@ -405,34 +339,16 @@ gb_internal void multi_map_get_all(PtrMap<K, V> *h, K key, V *items) {
 
 template <typename K, typename V>
 gb_internal void multi_map_insert(PtrMap<K, V> *h, K key, V const &value) {
-	MapFindResult fr;
-	MapIndex i;
-	if (h->hashes_count == 0) {
-		map_grow(h);
-	}
-	// Make
-	fr = map__find(h, key);
-	i = map__add_entry(h, key);
-	if (fr.entry_prev == MAP_SENTINEL) {
-		h->hashes[fr.hash_index] = i;
-	} else {
-		h->entries[fr.entry_prev].next = i;
-	}
-	h->entries[i].next = fr.entry_index;
-	h->entries[i].value = value;
-	// Grow if needed
-	if (map__full(h)) {
-		map_grow(h);
-	}
+	try_map_grow(h);
+	map__insert(h, key, value);
 }
 
-template <typename K, typename V>
-gb_internal void multi_map_remove(PtrMap<K, V> *h, K key, PtrMapEntry<K, V> *e) {
-	MapFindResult fr = map__find_from_entry(h, e);
-	if (fr.entry_index != MAP_SENTINEL) {
-		map__erase(h, fr);
-	}
-}
+// template <typename K, typename V>
+// gb_internal void multi_map_remove(PtrMap<K, V> *h, K key, PtrMapEntry<K, V> *e) {
+// 	if (fr.entry_index != MAP_SENTINEL) {
+// 		map__erase(h, fr);
+// 	}
+// }
 
 template <typename K, typename V>
 gb_internal void multi_map_remove_all(PtrMap<K, V> *h, K key) {
@@ -443,22 +359,77 @@ gb_internal void multi_map_remove_all(PtrMap<K, V> *h, K key) {
 #endif
 
 
+
+
+template <typename K, typename V>
+struct PtrMapIterator {
+	PtrMap<K, V> *map;
+	MapIndex index;
+
+	PtrMapIterator<K, V> &operator++() noexcept {
+		for (;;) {
+			++index;
+			if (map->capacity == index) {
+				return *this;
+			}
+			PtrMapEntry<K, V> *entry = map->entries+index;
+			if (entry->key && entry->key != cast(K)MAP_TOMBSTONE) {
+				return *this;
+			}
+		}
+	}
+
+	bool operator==(PtrMapIterator<K, V> const &other) const noexcept {
+		return this->map == other->map && this->index == other->index;
+	}
+
+	operator PtrMapEntry<K, V> *() const {
+		return map->entries+index;
+	}
+};
+
+
 template <typename K, typename V>
-gb_internal PtrMapEntry<K, V> *begin(PtrMap<K, V> &m) {
-	return m.entries;
+gb_internal PtrMapIterator<K, V> end(PtrMap<K, V> &m) noexcept {
+	return PtrMapIterator<K, V>{&m, m.capacity};
 }
+
 template <typename K, typename V>
-gb_internal PtrMapEntry<K, V> const *begin(PtrMap<K, V> const &m) {
-	return m.entries;
+gb_internal PtrMapIterator<K, V> const end(PtrMap<K, V> const &m) noexcept {
+	return PtrMapIterator<K, V>{&m, m.capacity};
 }
 
 
+
 template <typename K, typename V>
-gb_internal PtrMapEntry<K, V> *end(PtrMap<K, V> &m) {
-	return m.entries + m.count;
-}
+gb_internal PtrMapIterator<K, V> begin(PtrMap<K, V> &m) noexcept {
+	if (m.count == 0) {
+		return end(m);
+	}
 
+	MapIndex index = 0;
+	while (index < m.capacity) {
+		auto key = m.entries[index].key;
+		if (key && key != cast(K)MAP_TOMBSTONE) {
+			break;
+		}
+		index++;
+	}
+	return PtrMapIterator<K, V>{&m, index};
+}
 template <typename K, typename V>
-gb_internal PtrMapEntry<K, V> const *end(PtrMap<K, V> const &m) {
-	return m.entries + m.count;
+gb_internal PtrMapIterator<K, V> const begin(PtrMap<K, V> const &m) noexcept {
+	if (m.count == 0) {
+		return end(m);
+	}
+
+	MapIndex index = 0;
+	while (index < m.capacity) {
+		auto key = m.entries[index].key;
+		if (key && key != cast(K)MAP_TOMBSTONE) {
+			break;
+		}
+		index++;
+	}
+	return PtrMapIterator<K, V>{&m, index};
 }