Event/RawFile/include/RawFile/RawDataCache.h

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#ifndef RAW_DATA_CACHE_H
#define RAW_DATA_CACHE_H
 
#include <cstdint>
#include <cstdlib>
#include <zlib.h>
 
class RawDataCache final
{
    public:
        RawDataCache() = default;
        RawDataCache(uint64_t size);
        ~RawDataCache();
 
        template<typename T>
            T* data() { return reinterpret_cast<T*>(m_data); }
 
        uint64_t capacity() { return m_capacity; }   // in bytes
 
        // expand the cache size if necessary
        template<typename T>
            T *reserve(uint64_t size) {
                if (uint64_t _size = size * sizeof(T); m_capacity < _size) {
                    free(m_data);
                    if (m_capacity == 0) m_capacity = 128*1024;
                    do {
                        m_capacity *= 2;
                    } while (m_capacity < _size);
                    m_data = malloc(m_capacity);
                }
                return reinterpret_cast<T*>(m_data);
            }
 
        // expand the cache size and keep the original data if necessary
        template<typename T>
            T *expand(uint64_t size) {
                if (uint64_t _size = size * sizeof(T); m_capacity < _size) {
                    do {
                        m_capacity *= 2;
                    } while (m_capacity < _size);
                    m_data = realloc(m_data, m_capacity);
                }
                return reinterpret_cast<T*>(m_data);
            }
 
    private:
        void *m_data{nullptr};
        uint64_t m_capacity{0};
 
        RawDataCache(const RawDataCache &) = delete;
        RawDataCache &operator=(const RawDataCache &) = delete;
};
 
#endif