hashmap.h

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// TRAMWAY DRIFT AND DUNGEON EXPLORATION SIMULATOR 2022
// All rights reserved.
 
#ifndef TRAM_SDK_TEMPLATES_HASHMAP_H
#define TRAM_SDK_TEMPLATES_HASHMAP_H
 
#include <framework/uid.h>
#include <iostream> // error message
 
namespace tram {
 
template <typename T>
class Hashmap {
public:
    Hashmap(std::string name, size_t max_size) {
        this->name = name;
        this->max_size = max_size;
        
        size_t memory_size = ((max_size * 2) + padding) * sizeof(PAIR);
        
        char* memory = (char*)::operator new(memory_size);
        
        first = (PAIR*) memory;
        last = (PAIR*) (memory + memory_size);
        
        for (PAIR* it = first; it != last; it++) new (it) PAIR(); // wait what the fuck
    }
    
    Hashmap(std::string name, size_t max_size, std::initializer_list<std::pair<uint64_t, T>> list) : Hashmap(name, max_size) {
        for (const auto& entry : list) {
            Insert(entry.first, entry.second);
        }
    }
    
    T Find(UID key) {
        return Find(key.key);
    }
    
    T Find(uint64_t key) {
        uint64_t hash = key % max_size;
        
        PAIR* candidate = first + hash;
        
        while (candidate != last) {
            if (candidate->first == key) {
                return candidate->second;
            }
            
            if (candidate->first == 0) {
                break;
            }
            
            candidate++;
        }
        
        return T();
    }
    
    void Insert(UID key, T value) {
        Insert(key.key, value);
    }
    
    void Insert(uint64_t key, T value) {
        if(size == max_size){
            std::cout << "Hashmap " << name << " density reached!" << std::endl;
        }
        
        uint64_t hash = key % max_size;
        
        PAIR* candidate = first + hash;
        
        while (candidate != last) {
            if (candidate->first == key) {
                candidate->second.~T();
                break;
            }
            
            if (candidate->first == 0) {
                break;
            }
            
            candidate++;
        }
        
        if (candidate == last) {
            std::cout << "Hashmap " << name << " overflow!" << std::endl;
            abort();
        }
        
        candidate->first = key;
        candidate->second = value;
    }
protected:
    typedef std::pair<uint64_t, T> PAIR;
    const size_t padding = 10;
 
    std::string name;
    size_t size = 0;
    size_t max_size = 0;
    PAIR* first = nullptr;
    PAIR* last = nullptr;
};
 
}
 
#endif // TRAM_SDK_TEMPLATES_HASHMAP_H