// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. #ifndef ESP_NVS_H #define ESP_NVS_H #include <stdint.h> #include <stddef.h> #include <stdbool.h> #include "esp_attr.h" #include "esp_err.h" #ifdef __cplusplus extern "C" { #endif /** * Opaque pointer type representing non-volatile storage handle */ typedef uint32_t nvs_handle_t; /* * Pre-IDF V4.0 uses nvs_handle, so leaving the original typedef here for compatibility. */ typedef nvs_handle_t nvs_handle IDF_DEPRECATED("Replace with nvs_handle_t"); #define ESP_ERR_NVS_BASE 0x1100 /*!< Starting number of error codes */ #define ESP_ERR_NVS_NOT_INITIALIZED (ESP_ERR_NVS_BASE + 0x01) /*!< The storage driver is not initialized */ #define ESP_ERR_NVS_NOT_FOUND (ESP_ERR_NVS_BASE + 0x02) /*!< Id namespace doesn’t exist yet and mode is NVS_READONLY */ #define ESP_ERR_NVS_TYPE_MISMATCH (ESP_ERR_NVS_BASE + 0x03) /*!< The type of set or get operation doesn't match the type of value stored in NVS */ #define ESP_ERR_NVS_READ_ONLY (ESP_ERR_NVS_BASE + 0x04) /*!< Storage handle was opened as read only */ #define ESP_ERR_NVS_NOT_ENOUGH_SPACE (ESP_ERR_NVS_BASE + 0x05) /*!< There is not enough space in the underlying storage to save the value */ #define ESP_ERR_NVS_INVALID_NAME (ESP_ERR_NVS_BASE + 0x06) /*!< Namespace name doesn’t satisfy constraints */ #define ESP_ERR_NVS_INVALID_HANDLE (ESP_ERR_NVS_BASE + 0x07) /*!< Handle has been closed or is NULL */ #define ESP_ERR_NVS_REMOVE_FAILED (ESP_ERR_NVS_BASE + 0x08) /*!< The value wasn’t updated because flash write operation has failed. The value was written however, and update will be finished after re-initialization of nvs, provided that flash operation doesn’t fail again. */ #define ESP_ERR_NVS_KEY_TOO_LONG (ESP_ERR_NVS_BASE + 0x09) /*!< Key name is too long */ #define ESP_ERR_NVS_PAGE_FULL (ESP_ERR_NVS_BASE + 0x0a) /*!< Internal error; never returned by nvs API functions */ #define ESP_ERR_NVS_INVALID_STATE (ESP_ERR_NVS_BASE + 0x0b) /*!< NVS is in an inconsistent state due to a previous error. Call nvs_flash_init and nvs_open again, then retry. */ #define ESP_ERR_NVS_INVALID_LENGTH (ESP_ERR_NVS_BASE + 0x0c) /*!< String or blob length is not sufficient to store data */ #define ESP_ERR_NVS_NO_FREE_PAGES (ESP_ERR_NVS_BASE + 0x0d) /*!< NVS partition doesn't contain any empty pages. This may happen if NVS partition was truncated. Erase the whole partition and call nvs_flash_init again. */ #define ESP_ERR_NVS_VALUE_TOO_LONG (ESP_ERR_NVS_BASE + 0x0e) /*!< String or blob length is longer than supported by the implementation */ #define ESP_ERR_NVS_PART_NOT_FOUND (ESP_ERR_NVS_BASE + 0x0f) /*!< Partition with specified name is not found in the partition table */ #define ESP_ERR_NVS_NEW_VERSION_FOUND (ESP_ERR_NVS_BASE + 0x10) /*!< NVS partition contains data in new format and cannot be recognized by this version of code */ #define ESP_ERR_NVS_XTS_ENCR_FAILED (ESP_ERR_NVS_BASE + 0x11) /*!< XTS encryption failed while writing NVS entry */ #define ESP_ERR_NVS_XTS_DECR_FAILED (ESP_ERR_NVS_BASE + 0x12) /*!< XTS decryption failed while reading NVS entry */ #define ESP_ERR_NVS_XTS_CFG_FAILED (ESP_ERR_NVS_BASE + 0x13) /*!< XTS configuration setting failed */ #define ESP_ERR_NVS_XTS_CFG_NOT_FOUND (ESP_ERR_NVS_BASE + 0x14) /*!< XTS configuration not found */ #define ESP_ERR_NVS_ENCR_NOT_SUPPORTED (ESP_ERR_NVS_BASE + 0x15) /*!< NVS encryption is not supported in this version */ #define ESP_ERR_NVS_KEYS_NOT_INITIALIZED (ESP_ERR_NVS_BASE + 0x16) /*!< NVS key partition is uninitialized */ #define ESP_ERR_NVS_CORRUPT_KEY_PART (ESP_ERR_NVS_BASE + 0x17) /*!< NVS key partition is corrupt */ #define ESP_ERR_NVS_CONTENT_DIFFERS (ESP_ERR_NVS_BASE + 0x18) /*!< Internal error; never returned by nvs API functions. NVS key is different in comparison */ #define NVS_DEFAULT_PART_NAME "nvs" /*!< Default partition name of the NVS partition in the partition table */ #define NVS_PART_NAME_MAX_SIZE 16 /*!< maximum length of partition name (excluding null terminator) */ /** * @brief Mode of opening the non-volatile storage */ typedef enum { NVS_READONLY, /*!< Read only */ NVS_READWRITE /*!< Read and write */ } nvs_open_mode_t; /* * Pre-IDF V4.0 uses nvs_open_mode, so leaving the original typedef here for compatibility. */ typedef nvs_open_mode_t nvs_open_mode IDF_DEPRECATED("Replace with nvs_open_mode_t"); /** * @brief Types of variables * */ 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_ANY = 0xff /*!< Must be last */ } nvs_type_t; /** * @brief information about entry obtained from nvs_entry_info function */ typedef struct { char namespace_name[16]; /*!< Namespace to which key-value belong */ char key[16]; /*!< Key of stored key-value pair */ nvs_type_t type; /*!< Type of stored key-value pair */ } nvs_entry_info_t; /** * Opaque pointer type representing iterator to nvs entries */ typedef struct nvs_opaque_iterator_t *nvs_iterator_t; /** * @brief Open non-volatile storage with a given namespace from the default NVS partition * * Multiple internal ESP-IDF and third party application modules can store * their key-value pairs in the NVS module. In order to reduce possible * conflicts on key names, each module can use its own namespace. * The default NVS partition is the one that is labelled "nvs" in the partition * table. * * @param[in] name Namespace name. Maximal length is determined by the * underlying implementation, but is guaranteed to be * at least 15 characters. Shouldn't be empty. * @param[in] open_mode NVS_READWRITE or NVS_READONLY. If NVS_READONLY, will * open a handle for reading only. All write requests will * be rejected for this handle. * @param[out] out_handle If successful (return code is zero), handle will be * returned in this argument. * * @return * - ESP_OK if storage handle was opened successfully * - ESP_ERR_NVS_NOT_INITIALIZED if the storage driver is not initialized * - ESP_ERR_NVS_PART_NOT_FOUND if the partition with label "nvs" is not found * - ESP_ERR_NVS_NOT_FOUND id namespace doesn't exist yet and * mode is NVS_READONLY * - ESP_ERR_NVS_INVALID_NAME if namespace name doesn't satisfy constraints * - other error codes from the underlying storage driver */ esp_err_t nvs_open(const char* name, nvs_open_mode_t open_mode, nvs_handle_t *out_handle); /** * @brief Open non-volatile storage with a given namespace from specified partition * * The behaviour is same as nvs_open() API. However this API can operate on a specified NVS * partition instead of default NVS partition. Note that the specified partition must be registered * with NVS using nvs_flash_init_partition() API. * * @param[in] part_name Label (name) of the partition of interest for object read/write/erase * @param[in] name Namespace name. Maximal length is determined by the * underlying implementation, but is guaranteed to be * at least 15 characters. Shouldn't be empty. * @param[in] open_mode NVS_READWRITE or NVS_READONLY. If NVS_READONLY, will * open a handle for reading only. All write requests will * be rejected for this handle. * @param[out] out_handle If successful (return code is zero), handle will be * returned in this argument. * * @return * - ESP_OK if storage handle was opened successfully * - ESP_ERR_NVS_NOT_INITIALIZED if the storage driver is not initialized * - ESP_ERR_NVS_PART_NOT_FOUND if the partition with specified name is not found * - ESP_ERR_NVS_NOT_FOUND id namespace doesn't exist yet and * mode is NVS_READONLY * - ESP_ERR_NVS_INVALID_NAME if namespace name doesn't satisfy constraints * - other error codes from the underlying storage driver */ esp_err_t nvs_open_from_partition(const char *part_name, const char* name, nvs_open_mode_t open_mode, nvs_handle_t *out_handle); /**@{*/ /** * @brief set int8_t value for given key * * Set value for the key, given its name. Note that the actual storage will not be updated * until \c nvs_commit is called. * * @param[in] handle Handle obtained from nvs_open function. * Handles that were opened read only cannot be used. * @param[in] key Key name. Maximal length is determined by the underlying * implementation, but is guaranteed to be at least * 15 characters. Shouldn't be empty. * @param[in] value The value to set. * * @return * - ESP_OK if value was set successfully * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_READ_ONLY if storage handle was opened as read only * - ESP_ERR_NVS_INVALID_NAME if key name doesn't satisfy constraints * - ESP_ERR_NVS_NOT_ENOUGH_SPACE if there is not enough space in the * underlying storage to save the value * - ESP_ERR_NVS_REMOVE_FAILED if the value wasn't updated because flash * write operation has failed. The value was written however, and * update will be finished after re-initialization of nvs, provided that * flash operation doesn't fail again. */ esp_err_t nvs_set_i8 (nvs_handle_t handle, const char* key, int8_t value); /** * @brief set uint8_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_u8 (nvs_handle_t handle, const char* key, uint8_t value); /** * @brief set int16_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_i16 (nvs_handle_t handle, const char* key, int16_t value); /** * @brief set uint16_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_u16 (nvs_handle_t handle, const char* key, uint16_t value); /** * @brief set int32_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_i32 (nvs_handle_t handle, const char* key, int32_t value); /** * @brief set uint32_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_u32 (nvs_handle_t handle, const char* key, uint32_t value); /** * @brief set int64_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_i64 (nvs_handle_t handle, const char* key, int64_t value); /** * @brief set uint64_t value for given key * * This function is the same as \c nvs_set_i8 except for the data type. */ esp_err_t nvs_set_u64 (nvs_handle_t handle, const char* key, uint64_t value); /** * @brief set string for given key * * Set value for the key, given its name. Note that the actual storage will not be updated * until \c nvs_commit is called. * * @param[in] handle Handle obtained from nvs_open function. * Handles that were opened read only cannot be used. * @param[in] key Key name. Maximal length is (NVS_KEY_NAME_MAX_SIZE-1) characters. Shouldn't be empty. * @param[in] value The value to set. * For strings, the maximum length (including null character) is * 4000 bytes, if there is one complete page free for writing. * This decreases, however, if the free space is fragmented. * * @return * - ESP_OK if value was set successfully * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_READ_ONLY if storage handle was opened as read only * - ESP_ERR_NVS_INVALID_NAME if key name doesn't satisfy constraints * - ESP_ERR_NVS_NOT_ENOUGH_SPACE if there is not enough space in the * underlying storage to save the value * - ESP_ERR_NVS_REMOVE_FAILED if the value wasn't updated because flash * write operation has failed. The value was written however, and * update will be finished after re-initialization of nvs, provided that * flash operation doesn't fail again. * - ESP_ERR_NVS_VALUE_TOO_LONG if the string value is too long */ esp_err_t nvs_set_str (nvs_handle_t handle, const char* key, const char* value); /**@}*/ /** * @brief set variable length binary value for given key * * This family of functions set value for the key, given its name. Note that * actual storage will not be updated until nvs_commit function is called. * * @param[in] handle Handle obtained from nvs_open function. * Handles that were opened read only cannot be used. * @param[in] key Key name. Maximal length is 15 characters. Shouldn't be empty. * @param[in] value The value to set. * @param[in] length length of binary value to set, in bytes; Maximum length is * 508000 bytes or (97.6% of the partition size - 4000) bytes * whichever is lower. * * @return * - ESP_OK if value was set successfully * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_READ_ONLY if storage handle was opened as read only * - ESP_ERR_NVS_INVALID_NAME if key name doesn't satisfy constraints * - ESP_ERR_NVS_NOT_ENOUGH_SPACE if there is not enough space in the * underlying storage to save the value * - ESP_ERR_NVS_REMOVE_FAILED if the value wasn't updated because flash * write operation has failed. The value was written however, and * update will be finished after re-initialization of nvs, provided that * flash operation doesn't fail again. * - ESP_ERR_NVS_VALUE_TOO_LONG if the value is too long */ esp_err_t nvs_set_blob(nvs_handle_t handle, const char* key, const void* value, size_t length); /**@{*/ /** * @brief get int8_t value for given key * * These functions retrieve value for the key, given its name. If \c key does not * exist, or the requested variable type doesn't match the type which was used * when setting a value, an error is returned. * * In case of any error, out_value is not modified. * * \c out_value has to be a pointer to an already allocated variable of the given type. * * \code{c} * // Example of using nvs_get_i32: * int32_t max_buffer_size = 4096; // default value * esp_err_t err = nvs_get_i32(my_handle, "max_buffer_size", &max_buffer_size); * assert(err == ESP_OK || err == ESP_ERR_NVS_NOT_FOUND); * // if ESP_ERR_NVS_NOT_FOUND was returned, max_buffer_size will still * // have its default value. * * \endcode * * @param[in] handle Handle obtained from nvs_open function. * @param[in] key Key name. Maximal length is determined by the underlying * implementation, but is guaranteed to be at least * 15 characters. Shouldn't be empty. * @param out_value Pointer to the output value. * May be NULL for nvs_get_str and nvs_get_blob, in this * case required length will be returned in length argument. * * @return * - ESP_OK if the value was retrieved successfully * - ESP_ERR_NVS_NOT_FOUND if the requested key doesn't exist * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_INVALID_NAME if key name doesn't satisfy constraints * - ESP_ERR_NVS_INVALID_LENGTH if length is not sufficient to store data */ esp_err_t nvs_get_i8 (nvs_handle_t handle, const char* key, int8_t* out_value); /** * @brief get uint8_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_u8 (nvs_handle_t handle, const char* key, uint8_t* out_value); /** * @brief get int16_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_i16 (nvs_handle_t handle, const char* key, int16_t* out_value); /** * @brief get uint16_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_u16 (nvs_handle_t handle, const char* key, uint16_t* out_value); /** * @brief get int32_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_i32 (nvs_handle_t handle, const char* key, int32_t* out_value); /** * @brief get uint32_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_u32 (nvs_handle_t handle, const char* key, uint32_t* out_value); /** * @brief get int64_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_i64 (nvs_handle_t handle, const char* key, int64_t* out_value); /** * @brief get uint64_t value for given key * * This function is the same as \c nvs_get_i8 except for the data type. */ esp_err_t nvs_get_u64 (nvs_handle_t handle, const char* key, uint64_t* out_value); /**@}*/ /**@{*/ /** * @brief get string value for given key * * These functions retrieve the data of an entry, given its key. If key does not * exist, or the requested variable type doesn't match the type which was used * when setting a value, an error is returned. * * In case of any error, out_value is not modified. * * All functions expect out_value to be a pointer to an already allocated variable * of the given type. * * nvs_get_str and nvs_get_blob functions support WinAPI-style length queries. * To get the size necessary to store the value, call nvs_get_str or nvs_get_blob * with zero out_value and non-zero pointer to length. Variable pointed to * by length argument will be set to the required length. For nvs_get_str, * this length includes the zero terminator. When calling nvs_get_str and * nvs_get_blob with non-zero out_value, length has to be non-zero and has to * point to the length available in out_value. * It is suggested that nvs_get/set_str is used for zero-terminated C strings, and * nvs_get/set_blob used for arbitrary data structures. * * \code{c} * // Example (without error checking) of using nvs_get_str to get a string into dynamic array: * size_t required_size; * nvs_get_str(my_handle, "server_name", NULL, &required_size); * char* server_name = malloc(required_size); * nvs_get_str(my_handle, "server_name", server_name, &required_size); * * // Example (without error checking) of using nvs_get_blob to get a binary data * into a static array: * uint8_t mac_addr[6]; * size_t size = sizeof(mac_addr); * nvs_get_blob(my_handle, "dst_mac_addr", mac_addr, &size); * \endcode * * @param[in] handle Handle obtained from nvs_open function. * @param[in] key Key name. Maximal length is (NVS_KEY_NAME_MAX_SIZE-1) characters. Shouldn't be empty. * @param[out] out_value Pointer to the output value. * May be NULL for nvs_get_str and nvs_get_blob, in this * case required length will be returned in length argument. * @param[inout] length A non-zero pointer to the variable holding the length of out_value. * In case out_value a zero, will be set to the length * required to hold the value. In case out_value is not * zero, will be set to the actual length of the value * written. For nvs_get_str this includes zero terminator. * * @return * - ESP_OK if the value was retrieved successfully * - ESP_ERR_NVS_NOT_FOUND if the requested key doesn't exist * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_INVALID_NAME if key name doesn't satisfy constraints * - ESP_ERR_NVS_INVALID_LENGTH if \c length is not sufficient to store data */ esp_err_t nvs_get_str (nvs_handle_t handle, const char* key, char* out_value, size_t* length); /** * @brief get blob value for given key * * This function behaves the same as \c nvs_get_str, except for the data type. */ esp_err_t nvs_get_blob(nvs_handle_t handle, const char* key, void* out_value, size_t* length); /**@}*/ /** * @brief Erase key-value pair with given key name. * * Note that actual storage may not be updated until nvs_commit function is called. * * @param[in] handle Storage handle obtained with nvs_open. * Handles that were opened read only cannot be used. * * @param[in] key Key name. Maximal length is determined by the underlying * implementation, but is guaranteed to be at least * 15 characters. Shouldn't be empty. * * @return * - ESP_OK if erase operation was successful * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_READ_ONLY if handle was opened as read only * - ESP_ERR_NVS_NOT_FOUND if the requested key doesn't exist * - other error codes from the underlying storage driver */ esp_err_t nvs_erase_key(nvs_handle_t handle, const char* key); /** * @brief Erase all key-value pairs in a namespace * * Note that actual storage may not be updated until nvs_commit function is called. * * @param[in] handle Storage handle obtained with nvs_open. * Handles that were opened read only cannot be used. * * @return * - ESP_OK if erase operation was successful * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - ESP_ERR_NVS_READ_ONLY if handle was opened as read only * - other error codes from the underlying storage driver */ esp_err_t nvs_erase_all(nvs_handle_t handle); /** * @brief Write any pending changes to non-volatile storage * * After setting any values, nvs_commit() must be called to ensure changes are written * to non-volatile storage. Individual implementations may write to storage at other times, * but this is not guaranteed. * * @param[in] handle Storage handle obtained with nvs_open. * Handles that were opened read only cannot be used. * * @return * - ESP_OK if the changes have been written successfully * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL * - other error codes from the underlying storage driver */ esp_err_t nvs_commit(nvs_handle_t handle); /** * @brief Close the storage handle and free any allocated resources * * This function should be called for each handle opened with nvs_open once * the handle is not in use any more. Closing the handle may not automatically * write the changes to nonvolatile storage. This has to be done explicitly using * nvs_commit function. * Once this function is called on a handle, the handle should no longer be used. * * @param[in] handle Storage handle to close */ void nvs_close(nvs_handle_t handle); /** * @note Info about storage space NVS. */ typedef struct { size_t used_entries; /**< Amount of used entries. */ size_t free_entries; /**< Amount of free entries. */ size_t total_entries; /**< Amount all available entries. */ size_t namespace_count; /**< Amount name space. */ } nvs_stats_t; /** * @brief Fill structure nvs_stats_t. It provides info about used memory the partition. * * This function calculates to runtime the number of used entries, free entries, total entries, * and amount namespace in partition. * * \code{c} * // Example of nvs_get_stats() to get the number of used entries and free entries: * nvs_stats_t nvs_stats; * nvs_get_stats(NULL, &nvs_stats); * printf("Count: UsedEntries = (%d), FreeEntries = (%d), AllEntries = (%d)\n", nvs_stats.used_entries, nvs_stats.free_entries, nvs_stats.total_entries); * \endcode * * @param[in] part_name Partition name NVS in the partition table. * If pass a NULL than will use NVS_DEFAULT_PART_NAME ("nvs"). * * @param[out] nvs_stats Returns filled structure nvs_states_t. * It provides info about used memory the partition. * * * @return * - ESP_OK if the changes have been written successfully. * Return param nvs_stats will be filled. * - ESP_ERR_NVS_PART_NOT_FOUND if the partition with label "name" is not found. * Return param nvs_stats will be filled 0. * - ESP_ERR_NVS_NOT_INITIALIZED if the storage driver is not initialized. * Return param nvs_stats will be filled 0. * - ESP_ERR_INVALID_ARG if nvs_stats equal to NULL. * - ESP_ERR_INVALID_STATE if there is page with the status of INVALID. * Return param nvs_stats will be filled not with correct values because * not all pages will be counted. Counting will be interrupted at the first INVALID page. */ esp_err_t nvs_get_stats(const char *part_name, nvs_stats_t *nvs_stats); /** * @brief Calculate all entries in a namespace. * * An entry represents the smallest storage unit in NVS. * Strings and blobs may occupy more than one entry. * Note that to find out the total number of entries occupied by the namespace, * add one to the returned value used_entries (if err is equal to ESP_OK). * Because the name space entry takes one entry. * * \code{c} * // Example of nvs_get_used_entry_count() to get amount of all key-value pairs in one namespace: * nvs_handle_t handle; * nvs_open("namespace1", NVS_READWRITE, &handle); * ... * size_t used_entries; * size_t total_entries_namespace; * if(nvs_get_used_entry_count(handle, &used_entries) == ESP_OK){ * // the total number of entries occupied by the namespace * total_entries_namespace = used_entries + 1; * } * \endcode * * @param[in] handle Handle obtained from nvs_open function. * * @param[out] used_entries Returns amount of used entries from a namespace. * * * @return * - ESP_OK if the changes have been written successfully. * Return param used_entries will be filled valid value. * - ESP_ERR_NVS_NOT_INITIALIZED if the storage driver is not initialized. * Return param used_entries will be filled 0. * - ESP_ERR_NVS_INVALID_HANDLE if handle has been closed or is NULL. * Return param used_entries will be filled 0. * - ESP_ERR_INVALID_ARG if used_entries equal to NULL. * - Other error codes from the underlying storage driver. * Return param used_entries will be filled 0. */ esp_err_t nvs_get_used_entry_count(nvs_handle_t handle, size_t* used_entries); /** * @brief Create an iterator to enumerate NVS entries based on one or more parameters * * \code{c} * // Example of listing all the key-value pairs of any type under specified partition and namespace * nvs_iterator_t it = nvs_entry_find(partition, namespace, NVS_TYPE_ANY); * while (it != NULL) { * nvs_entry_info_t info; * nvs_entry_info(it, &info); * it = nvs_entry_next(it); * printf("key '%s', type '%d' \n", info.key, info.type); * }; * // Note: no need to release iterator obtained from nvs_entry_find function when * // nvs_entry_find or nvs_entry_next function return NULL, indicating no other * // element for specified criteria was found. * } * \endcode * * @param[in] part_name Partition name * * @param[in] namespace_name Set this value if looking for entries with * a specific namespace. Pass NULL otherwise. * * @param[in] type One of nvs_type_t values. * * @return * Iterator used to enumerate all the entries found, * or NULL if no entry satisfying criteria was found. * Iterator obtained through this function has to be released * using nvs_release_iterator when not used any more. */ nvs_iterator_t nvs_entry_find(const char *part_name, const char *namespace_name, nvs_type_t type); /** * @brief Returns next item matching the iterator criteria, NULL if no such item exists. * * Note that any copies of the iterator will be invalid after this call. * * @param[in] iterator Iterator obtained from nvs_entry_find function. Must be non-NULL. * * @return * NULL if no entry was found, valid nvs_iterator_t otherwise. */ nvs_iterator_t nvs_entry_next(nvs_iterator_t iterator); /** * @brief Fills nvs_entry_info_t structure with information about entry pointed to by the iterator. * * @param[in] iterator Iterator obtained from nvs_entry_find or nvs_entry_next function. Must be non-NULL. * * @param[out] out_info Structure to which entry information is copied. */ void nvs_entry_info(nvs_iterator_t iterator, nvs_entry_info_t *out_info); /** * @brief Release iterator * * @param[in] iterator Release iterator obtained from nvs_entry_find function. NULL argument is allowed. * */ void nvs_release_iterator(nvs_iterator_t iterator); #ifdef __cplusplus } // extern "C" #endif #endif //ESP_NVS_H