packed_storage.h

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 * Copyright (c) 2010-2020 OTClient <https://github.com/edubart/otclient>
 *
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 * of this software and associated documentation files (the "Software"), to deal
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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#ifndef STDEXT_PACKEDSTORAGE_H
#define STDEXT_PACKEDSTORAGE_H
 
#include "types.h"
#include "packed_any.h"
 
namespace stdext {
 
// disable memory alignment
#pragma pack(push,1)
 
// this class was designed to use less memory as possible
template<typename Key, typename SizeType = uint8>
class packed_storage {
    struct value_pair {
        Key id;
        packed_any value;
    };
 
public:
    packed_storage() : m_values(nullptr), m_size(0) { }
    ~packed_storage() { delete[] m_values; }
 
    template<typename T>
    void set(Key id, const T& value) {
        for(SizeType i=0;i<m_size;++i) {
            if(m_values[i].id == id) {
                m_values[i].value = value;
                return;
            }
        }
        auto tmp = new value_pair[m_size+1];
        if(m_size > 0) {
            std::copy(m_values, m_values + m_size, tmp);
            delete[] m_values;
        }
        m_values = tmp;
        m_values[m_size++] = { id, packed_any(value) };
    }
 
    bool remove(Key id) {
        auto begin = m_values;
        auto end = m_values + m_size;
        auto it = std::find_if(begin, end, [=](const value_pair& pair) -> bool { return pair.id == id; } );
        if(it == end)
            return false;
        int pos = it - begin;
        auto tmp = new value_pair[m_size-1];
        std::copy(begin, begin + pos, tmp);
        std::copy(begin + pos + 1, end, tmp + pos);
        delete[] m_values;
        m_values = tmp;
        m_size--;
        return true;
    }
 
    template<typename T>
    T get(Key id) const {
        for(SizeType i=0;i<m_size;++i)
            if(m_values[i].id == id)
                return packed_any_cast<T>(m_values[i].value);
        return T();
    }
 
    bool has(Key id) const {
        for(SizeType i=0;i<m_size;++i)
            if(m_values[i].id == id)
                return true;
        return false;
    }
 
    void clear() {
        if(m_values)
            delete [] m_values;
        m_values = nullptr;
        m_size = 0;
    }
 
    std::size_t size() { return m_size; }
 
private:
    value_pair *m_values;
    SizeType m_size;
};
 
// restore memory alignment
#pragma pack(pop)
 
}
 
#endif