Add support for floats to NVS (IDFGH-12814)

[kdschlosser]

Is your feature request related to a problem?

It would be nice to have the ability to store floats into NVRAM. It's not that hard to do using type punning. This is able to be achieved partly by the user with the get and set but the missing component is the NVS_TYPE when pulling the info for that key. You would not be able to identify it as a float via the info. It would end up being a U32 type.

Describe the solution you'd like.

From what I am seeing this is what would need to be done.

nvs.h

typedef enum {
    NVS_TYPE_U8    = 0x01,  /*!< Type uint8_t */
    NVS_TYPE_I8    = 0x11,  /*!< Type int8_t */
    NVS_TYPE_U16   = 0x02,  /*!< Type uint16_t */
    NVS_TYPE_I16   = 0x12,  /*!< Type int16_t */
    NVS_TYPE_U32   = 0x04,  /*!< Type uint32_t */
    NVS_TYPE_I32   = 0x14,  /*!< Type int32_t */
    NVS_TYPE_U64   = 0x08,  /*!< Type uint64_t */
    NVS_TYPE_I64   = 0x18,  /*!< Type int64_t */
    NVS_TYPE_STR   = 0x21,  /*!< Type string */
    NVS_TYPE_BLOB  = 0x42,  /*!< Type blob */
    NVS_TYPE_FLOAT = 0x24,  /*!< Type float */
    NVS_TYPE_ANY   = 0xff   /*!< Must be last */
} nvs_type_t;


esp_err_t nvs_get_float (nvs_handle_t handle, const char *key, float *value);

esp_err_t nvs_set_float(nvs_handle_t c_handle, const char* key, float value);

nvs_api.cpp

extern "C" esp_err_t nvs_get_float (nvs_handle_t c_handle, const char* key, float* out_value)
{
    Lock lock;
    ESP_LOGD(TAG, "%s %s", __func__, key);
    NVSHandleSimple *handle;
    auto err = nvs_find_ns_handle(c_handle, &handle);
    if (err != ESP_OK) {
        return err;
    }

    return handle->get_float(key, out_value);
}


extern "C" esp_err_t nvs_set_float(nvs_handle_t c_handle, const char* key, float in_float)
{
    Lock lock;
    ESP_LOGD(TAG, "%s %s %f", __func__, key, in_float);
    NVSHandleSimple *handle;
    auto err = nvs_find_ns_handle(c_handle, &handle);
    if (err != ESP_OK) {
        return err;
    }

    return handle->set_float(key, in_float);
}

nvs_handle.hpp

enum class ItemType : uint8_t {
    U8   = NVS_TYPE_U8,
    I8   = NVS_TYPE_I8,
    U16  = NVS_TYPE_U16,
    I16  = NVS_TYPE_I16,
    U32  = NVS_TYPE_U32,
    I32  = NVS_TYPE_I32,
    U64  = NVS_TYPE_U64,
    I64  = NVS_TYPE_I64,
    SZ   = NVS_TYPE_STR,
    BLOB = 0x41,
    BLOB_DATA = NVS_TYPE_BLOB,
    BLOB_IDX  = 0x48,
    FLOAT = NVS_TYPE_FLOAT,
    ANY  = NVS_TYPE_ANY
};

virtual esp_err_t get_float(const char *key, float* out_float) = 0;
virtual esp_err_t set_float(const char *key, float in_float) = 0;

nvs_handle_locked.cpp

esp_err_t NVSHandleLocked::get_float(const char *key, float* out_float) {
    Lock lock;
    return handle->get_float(key, out_float);
}

esp_err_t NVSHandleLocked::set_float(const char *key, float in_float) {
    Lock lock;
    return handle->set_float(key, in_float);
}

nvs_handle_simple.cpp

esp_err_t NVSHandleSimple::get_float(const char *key, float* out_float)
{
    if (!valid) return ESP_ERR_NVS_INVALID_HANDLE;

    out_float
    union {float f; uint32_t i;} u;

    auto err = mStoragePtr->readItem(mNsIndex, nvs::ItemType::FLOAT, key, &u.i, 4);
    if (err != ESP_OK) {
        return err;
    }

    *out_float = u.f;
    return err;
}


esp_err_t NVSHandleSimple::set_float(const char *key, float in_float)
{
    if (!valid) return ESP_ERR_NVS_INVALID_HANDLE;
    if (mReadOnly) return ESP_ERR_NVS_READ_ONLY;

    union {float f; uint32_t i;} u;
    u.f = in_float;

    return mStoragePtr->writeItem(mNsIndex, nvs::ItemType::FLOAT, key, u.i, 4);
}

I could be missing some thing. C and CPP is not my strong language. It would however be nice to see this ability added to the esp-idf

Describe alternatives you've considered.

No response

Additional context.

No response