Class DMABuffer

src/platforms/shared/spi_types.h:44–81

@brief Result type for DMA buffer acquisition @details Returns either a valid buffer span or an error code @note Buffer uses shared_ptr for lifetime management (important for async DMA) @note Internally holds fl::vector with allocator_psram for efficient DMA operations

/// @note Buffer uses shared_ptr for lifetime management (important for async DMA)
/// @note Internally holds fl::vector with allocator_psram for efficient DMA operations
struct DMABuffer {
private:
    fl::shared_ptr<DMABufferInternalData> mInternal;  ///< Shared ownership of internal data
    SPIError error_code;
    bool is_ok;

public:
    /// @brief Default constructor (uninitialized error state)
    DMABuffer() FL_NOEXCEPT;

    /// @brief Construct successful result with buffer size
    /// @param size Size of buffer in bytes to allocate
    explicit DMABuffer(size_t size) FL_NOEXCEPT;

    /// @brief Construct successful result with buffer pointer and size (legacy compatibility)
    /// @param ptr Shared pointer to buffer data
    /// @param size Size of buffer in bytes
    /// @deprecated Use DMABuffer(size_t) constructor instead
    DMABuffer(fl::shared_ptr<u8> ptr, size_t size) FL_NOEXCEPT;

    /// @brief Construct error result
    explicit DMABuffer(SPIError err) FL_NOEXCEPT;

    /// @brief Check if buffer acquisition succeeded
    bool ok() const FL_NOEXCEPT;

    /// @brief Get the buffer span (only valid if ok() returns true)
    fl::span<u8> data() const FL_NOEXCEPT;

    /// @brief Get the error code (only meaningful if ok() returns false)
    SPIError error() const FL_NOEXCEPT;

    /// @brief Reset/clear the buffer (invalidates internal data)
    void reset() FL_NOEXCEPT;

    /// @brief Get the size of the buffer in bytes
    size_t size() const FL_NOEXCEPT;
};

/// @brief Request structure for SPI transmit operations
/// @details Contains the DMA buffer and transmission mode