Add Heap and HashTable

Author: Kyle-Ye

Sources/OpenGraphCxx/Util/HashTable.cpp

@@ -0,0 +1,306 @@
+//
+//  HashTable.cpp
+//  OpenGraphCxx
+//
+//  Status: Complete
+//  Modified based Compute code
+
+#include <OpenGraphCxx/Util/HashTable.hpp>
+#include <OpenGraphCxx/Util/Heap.hpp>
+#include <memory>
+
+namespace util {
+
+uint64_t pointer_hash(void const *pointer) {
+    int64_t result = (-1 ^ (int64_t)(pointer) << 0x20) + (int64_t)pointer;
+    result = result ^ result >> 0x16;
+    result = result + (-1 ^ result << 0xd);
+    result = (result ^ result >> 8) * 9;
+    result = result ^ result >> 0xf;
+    result = result + (-1 ^ result << 0x1b);
+    return result ^ result >> 0x1f;
+}
+
+bool pointer_compare(void const *a, void const *b) { return a == b; }
+
+uint64_t string_hash(char const *str) {
+    int64_t result = 0;
+    for (char const *c = str; *c; c += 1) {
+        result = result * 33 + *c;
+    }
+    return result;
+}
+
+constexpr uint32_t initial_bucket_mask_width = 4;
+
+UntypedTable *UntypedTable::create() { return new UntypedTable(); }
+
+void UntypedTable::destroy(UntypedTable *value) { delete value; }
+
+UntypedTable::UntypedTable() {
+    _hash = pointer_hash;
+    _compare = pointer_compare;
+    _did_remove_key = nullptr;
+    _did_remove_value = nullptr;
+    _heap = nullptr;
+    _spare_node = 0;
+    _buckets = nullptr;
+    _count = 0;
+    _bucket_mask = 0;
+    _bucket_mask_width = 0;
+    _is_heap_owner = true;
+    _compare_by_pointer = true;
+}
+
+UntypedTable::UntypedTable(hasher custom_hash, key_equal custom_compare, key_callback did_remove_key,
+                           value_callback did_remove_value, Heap *heap) {
+    _hash = custom_hash != nullptr ? custom_hash : pointer_hash;
+    _compare = custom_compare != nullptr ? custom_compare : pointer_compare;
+    _did_remove_key = did_remove_key;
+    _did_remove_value = did_remove_value;
+    _heap = heap;
+    _spare_node = 0;
+    _buckets = nullptr;
+    _count = 0;
+    _bucket_mask = 0;
+    _bucket_mask_width = 0;
+    _is_heap_owner = heap == nullptr;
+    _compare_by_pointer = custom_compare == nullptr || custom_compare == pointer_compare;
+}
+
+UntypedTable::~UntypedTable() {
+    if ((_did_remove_key || _did_remove_value) && _count) {
+        for (uint32_t bucket = 0; !(bucket >> _bucket_mask_width); bucket++) {
+            for (HashNode *node = _buckets[bucket]; node != nullptr; node = node->next) {
+                if (_did_remove_key) {
+                    _did_remove_key(node->key);
+                }
+                if (_did_remove_value) {
+                    _did_remove_value(node->value);
+                }
+            }
+        }
+    }
+    if (_bucket_mask_width > initial_bucket_mask_width) {
+        free(_buckets);
+    }
+    if (_is_heap_owner && _heap) {
+        delete _heap;
+    }
+}
+
+#pragma mark - Managing buckets
+
+// Buckets are initially allocated by the util::Heap instance,
+// until they grow past initial_bucket_mask_width where they are allocated using new.ˆ
+
+void UntypedTable::create_buckets() {
+    if (_buckets != nullptr) {
+        return;
+    }
+
+    _bucket_mask_width = initial_bucket_mask_width;
+    _bucket_mask = (1 << initial_bucket_mask_width) - 1;
+
+    if (_heap == nullptr) {
+        _heap = new Heap(nullptr, 0, Heap::minimum_increment);
+    }
+
+    size_t num_buckets = (1 << initial_bucket_mask_width);
+    _buckets = _heap->alloc<Bucket>(num_buckets);
+    std::memset(_buckets, 0, sizeof(Bucket) * num_buckets);
+}
+
+void UntypedTable::grow_buckets() {
+    if (_bucket_mask_width > 30) {
+        return;
+    }
+
+    uint32_t old_width = _bucket_mask_width;
+    _bucket_mask_width = old_width + 1;
+
+    Bucket *old_buckets = _buckets;
+    Bucket *new_buckets = nullptr;
+
+    size_t num_buckets = 1 << _bucket_mask_width;
+    if (_bucket_mask_width > initial_bucket_mask_width) {
+        new_buckets = new Bucket[num_buckets];
+    } else {
+        if (_heap == nullptr) {
+            _heap = new Heap(nullptr, 0, Heap::minimum_increment);
+        }
+        new_buckets = _heap->alloc<Bucket>(num_buckets);
+    }
+    std::memset(new_buckets, 0, sizeof(Bucket) * num_buckets);
+
+    // redistribute old buckets into new
+    if (new_buckets) {
+        _bucket_mask = num_buckets - 1;
+        for (uint32_t i = 0; !(i >> old_width); i++) {
+            for (UntypedTable::HashNode *node = old_buckets[i]; node != nullptr; node = node->next) {
+                uint64_t new_bucket = _bucket_mask & node->hash_value;
+                node->next = new_buckets[new_bucket];
+                new_buckets[new_bucket] = node;
+            }
+        }
+        _buckets = new_buckets;
+
+        if (old_width > initial_bucket_mask_width) {
+            delete old_buckets;
+        }
+    }
+}
+
+#pragma mark - Lookup
+
+UntypedTable::value_type UntypedTable::lookup(key_type key, nullable_key_type *found_key_out) const noexcept {
+    if (_count) {
+        uint64_t hash_value = _hash(key);
+        HashNode *node = _buckets[_bucket_mask & hash_value];
+        if (_compare_by_pointer) {
+            for (; node != nullptr; node = node->next) {
+                if (node->key == key) {
+                    if (found_key_out) {
+                        *found_key_out = node->key;
+                    }
+                    return node->value;
+                }
+            }
+        } else if (node) {
+            for (; node != nullptr; node = node->next) {
+                if (node->hash_value == hash_value && _compare(node->key, key)) {
+                    if (found_key_out) {
+                        *found_key_out = node->key;
+                    }
+                    return node->value;
+                }
+            }
+        }
+    }
+    if (found_key_out) {
+        *found_key_out = nullptr;
+    }
+    return nullptr;
+}
+
+#pragma mark - Modifying entries
+
+bool UntypedTable::insert(key_type key, value_type value) {
+    if (_buckets == nullptr) {
+        this->create_buckets();
+    }
+
+    void *result;
+
+    uint64_t hash_value = _hash(key);
+    HashNode *node = _buckets[hash_value & _bucket_mask];
+
+    // replace existing if match
+    for (; node != nullptr; node = node->next) {
+        if (node->hash_value == hash_value && _compare(node->key, key)) {
+            if (_did_remove_key) {
+                _did_remove_key(node->key);
+            }
+            if (_did_remove_value) {
+                _did_remove_value(node->value);
+            }
+            node->key = key;
+            node->value = value;
+            return false;
+        }
+    }
+
+    // insert new
+    if (_count + 1 > 4 << _bucket_mask_width) {
+        this->grow_buckets();
+    }
+    if (!_heap) {
+        _heap = new Heap(nullptr, 0, Heap::minimum_increment);
+    }
+
+    HashNode *inserted_node = _spare_node;
+    if (inserted_node) {
+        _spare_node = _spare_node->next;
+    } else {
+        inserted_node = _heap->alloc<HashNode>();
+    }
+
+    inserted_node->key = key;
+    inserted_node->value = value;
+    inserted_node->hash_value = hash_value;
+
+    uint64_t bucket = _bucket_mask & hash_value;
+    inserted_node->next = _buckets[bucket];
+    _buckets[bucket] = inserted_node;
+
+    _count += 1;
+
+    return true;
+}
+
+bool UntypedTable::remove(key_type key) {
+    if (_count == 0) {
+        return false;
+    }
+    if (_compare_by_pointer) {
+        return this->remove_ptr(key);
+    }
+    uint64_t hash_value = _hash(key);
+    HashNode *node = _buckets[_bucket_mask & hash_value];
+
+    for (HashNode *candidate = node; candidate != nullptr; candidate = candidate->next) {
+        if (candidate->hash_value == hash_value && _compare(candidate->key, key)) {
+            node->next = candidate->next;
+            if (_did_remove_key) {
+                _did_remove_key(candidate->key);
+            }
+            if (_did_remove_value) {
+                _did_remove_value(candidate->value);
+            }
+            candidate->next = _spare_node;
+            _spare_node = candidate;
+            _count -= 1;
+            return true;
+        }
+        node = candidate;
+    }
+
+    return false;
+}
+
+bool UntypedTable::remove_ptr(key_type key) {
+    if (_count == 0) {
+        return false;
+    }
+
+    HashNode *node = _buckets[_bucket_mask & _hash(key)];
+    for (HashNode *candidate = node; candidate != nullptr; candidate = candidate->next) {
+        if (candidate->key == key) {
+            node->next = candidate->next;
+            if (_did_remove_key) {
+                _did_remove_key(candidate->key);
+            }
+            if (_did_remove_value) {
+                _did_remove_value(candidate->value);
+            }
+            candidate->next = _spare_node;
+            _spare_node = candidate;
+            _count -= 1;
+            return true;
+        }
+        node = candidate;
+    }
+    return false;
+}
+
+void UntypedTable::for_each(entry_callback body, void *context) const {
+    if (_count) {
+        for (uint32_t i = 0; !(i >> _bucket_mask_width); i++) {
+            for (UntypedTable::HashNode *node = _buckets[i]; node != nullptr; node = node->next) {
+                body(node->key, node->value, context);
+            }
+        }
+    }
+}
+
+} /* namespace util */