Non-Volatile Storage

Key-value store backed by non-volatile memory. More...

Functions
int	ove_nvs_init (void)
	Initialise the non-volatile storage subsystem.
void	ove_nvs_deinit (void)
	Deinitialise the non-volatile storage subsystem.
int	ove_nvs_read (const char *key, void *buf, size_t buf_len, size_t *out_len)
	Read a value from non-volatile storage by key.
int	ove_nvs_write (const char *key, const void *data, size_t len)
	Write or update a value in non-volatile storage.
int	ove_nvs_erase (const char *key)
	Delete a key-value pair from non-volatile storage.

Detailed Description

Key-value store backed by non-volatile memory.

Provides a simple string-keyed binary value store persisted in non-volatile storage (e.g. flash, EEPROM). Keys are null-terminated strings; values are arbitrary byte blobs of any size supported by the backend.

The subsystem must be initialised once with ove_nvs_init before any read, write, or erase operations are performed.

Note

Requires CONFIG_OVE_NVS.

Function Documentation

ove_nvs_init()

int ove_nvs_init

(

void

)

Initialise the non-volatile storage subsystem.

Must be called once before any other ove_nvs_* function. Performs backend-specific mount and integrity checks.

Returns

OVE_OK on success, negative error code on failure.

Note

Requires CONFIG_OVE_NVS.

ove_nvs_deinit()

void ove_nvs_deinit

(

void

)

Deinitialise the non-volatile storage subsystem.

Flushes any pending writes and unmounts the NVS backend. After this call all other ove_nvs_* functions will fail until ove_nvs_init is called again.

Note

Requires CONFIG_OVE_NVS.

ove_nvs_read()

int ove_nvs_read	(	const char *	key,
		void *	buf,
		size_t	buf_len,
		size_t *	out_len
	)

Read a value from non-volatile storage by key.

Copies the value associated with key into buf. At most buf_len bytes are written. The actual size of the stored value is written to out_len when not NULL, which allows the caller to detect truncation or to perform a size query (pass NULL for buf and 0 for buf_len).

Parameters

[in]	key	Null-terminated key string.
[out]	buf	Buffer to receive the value, or NULL for size query.
[in]	buf_len	Size of buf in bytes.
[out]	out_len	Receives the actual stored value length in bytes, or NULL if not needed.

Returns

OVE_OK on success, OVE_ERR_NOT_FOUND if the key does not exist, or another negative error code on failure.

Note

Requires CONFIG_OVE_NVS.

ove_nvs_write()

int ove_nvs_write	(	const char *	key,
		const void *	data,
		size_t	len
	)

Write or update a value in non-volatile storage.

Associates key with the len bytes pointed to by data. If the key already exists its value is replaced. The write is committed to non-volatile storage before the function returns.

Parameters

[in]	key	Null-terminated key string.
[in]	data	Pointer to the value data to store.
[in]	len	Number of bytes to store.

Returns

OVE_OK on success, negative error code on failure.

Note

Requires CONFIG_OVE_NVS.

ove_nvs_erase()

int ove_nvs_erase

(

const char *

key

)

Delete a key-value pair from non-volatile storage.

Permanently removes the entry identified by key. Has no effect if the key does not exist.

Parameters

[in]

key

Null-terminated key string to erase.

Returns

OVE_OK on success, negative error code on failure.

Note

Requires CONFIG_OVE_NVS.