StmNvs.h

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#pragma once
 
#include "BaseNvs.h"
#include "StmTypes.h"
#include <cstring>
 
class StmNvs : public BaseNvs {
public:
    explicit StmNvs(const char* namespace_name = "default",
                    const hf_stm32_nvs_config_t& flash_config = hf_stm32_nvs_config_t()) noexcept;
 
    ~StmNvs() noexcept override;
 
    // ── BaseNvs overrides ────────────────────────────────────────────────
 
    hf_nvs_err_t Initialize() noexcept override;
    hf_nvs_err_t Deinitialize() noexcept override;
 
    hf_nvs_err_t SetU32(const char* key, hf_u32_t value) noexcept override;
    hf_nvs_err_t GetU32(const char* key, hf_u32_t& value) noexcept override;
 
    hf_nvs_err_t SetString(const char* key, const char* value) noexcept override;
    hf_nvs_err_t GetString(const char* key, char* buffer, size_t buffer_size,
                           size_t* actual_size = nullptr) noexcept override;
 
    hf_nvs_err_t SetBlob(const char* key, const void* data, size_t data_size) noexcept override;
    hf_nvs_err_t GetBlob(const char* key, void* buffer, size_t buffer_size,
                         size_t* actual_size = nullptr) noexcept override;
 
    hf_nvs_err_t EraseKey(const char* key) noexcept override;
    hf_nvs_err_t Commit() noexcept override;
    bool KeyExists(const char* key) noexcept override;
    hf_nvs_err_t GetSize(const char* key, size_t& size) noexcept override;
 
    const char* GetDescription() const noexcept override;
    size_t GetMaxKeyLength() const noexcept override;
    size_t GetMaxValueSize() const noexcept override;
 
    // ── STM32-specific ───────────────────────────────────────────────────
 
    const hf_stm32_nvs_config_t& GetFlashConfig() const noexcept { return flash_config_; }
 
    size_t GetEntryCount() const noexcept { return entry_count_; }
 
    size_t GetFreeSpace() const noexcept;
 
private:
    enum class EntryType : hf_u8_t {
        U32    = 0x01,
        STRING = 0x02,
        BLOB   = 0x03,
        ERASED = 0xFF
    };
 
    struct __attribute__((packed)) EntryHeader {
        hf_u8_t  key_length;      
        EntryType type;            
        hf_u16_t data_length;     
        hf_u32_t crc32;           
    };
 
    struct CacheEntry {
        char     key[64];          
        EntryType type;            
        hf_u8_t  data[256];       
        hf_u16_t data_length;     
        bool     dirty;           
        bool     erased;          
    };
 
    int FindCacheEntry(const char* key) const noexcept;
 
    int AddOrUpdateCache(const char* key, EntryType type,
                         const void* data, size_t data_size) noexcept;
 
    bool IsValidKey(const char* key) const noexcept;
 
    hf_nvs_err_t FlushToFlash() noexcept;
 
    hf_nvs_err_t LoadFromFlash() noexcept;
 
    static hf_u32_t ComputeCrc32(const void* data, size_t length) noexcept;
 
    hf_stm32_nvs_config_t flash_config_;        
    static constexpr size_t kMaxEntries = 64;    
    CacheEntry             cache_[kMaxEntries];  
    size_t                 entry_count_;          
    hf_u32_t               write_offset_;         
};