persistence.h File Reference

Persistence API for storing and restoring Anjay Lite state. More...

#include <anj/init.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>

Go to the source code of this file.

Data Structures
struct	anj_persistence_context_t

Macros
#define	ANJ_PERSISTENCE_MAGIC_MAX_SIZE   16

Typedefs
typedef int	anj_persistence_read_cb_t(void *ctx, void *buf, size_t size)
typedef int	anj_persistence_write_cb_t(void *ctx, const void *buf, size_t size)

Enumerations
enum	anj_persistence_direction_t { ANJ_PERSISTENCE_STORE = 0 , ANJ_PERSISTENCE_RESTORE }

Functions
anj_persistence_context_t	anj_persistence_store_context_create (anj_persistence_write_cb_t *write_cb, void *ctx)
anj_persistence_context_t	anj_persistence_restore_context_create (anj_persistence_read_cb_t *read_cb, void *ctx)
static anj_persistence_direction_t	anj_persistence_direction (const anj_persistence_context_t *ctx)
int	anj_persistence_bytes (const anj_persistence_context_t *ctx, void *inout_buffer, size_t buffer_size)
int	anj_persistence_string (const anj_persistence_context_t *ctx, char *inout_str, size_t out_max_size)
int	anj_persistence_magic (const anj_persistence_context_t *ctx, const void *magic, size_t magic_size)
static int	anj_persistence_bool (const anj_persistence_context_t *ctx, bool *inout_value)
static int	anj_persistence_u8 (const anj_persistence_context_t *ctx, uint8_t *inout_value)
static int	anj_persistence_u16 (const anj_persistence_context_t *ctx, uint16_t *inout_value)
static int	anj_persistence_u32 (const anj_persistence_context_t *ctx, uint32_t *inout_value)
static int	anj_persistence_u64 (const anj_persistence_context_t *ctx, uint64_t *inout_value)
static int	anj_persistence_i8 (const anj_persistence_context_t *ctx, int8_t *inout_value)
static int	anj_persistence_i16 (const anj_persistence_context_t *ctx, int16_t *inout_value)
static int	anj_persistence_i32 (const anj_persistence_context_t *ctx, int32_t *inout_value)
static int	anj_persistence_i64 (const anj_persistence_context_t *ctx, int64_t *inout_value)

Detailed Description

Persistence API for storing and restoring Anjay Lite state.

Provides a generic context/stream abstraction with read/write callbacks. Used by higher-level modules to serialize internal state, security information, or application data to a platform-specific medium.

Supports storing/restoring primitive types, strings, fixed-size buffers, and validating blobs with “magic” tags.

Note

The binary format is not portable across architectures or compiler ABIs. Persisted data is only guaranteed to be valid on the same platform/build.

Macro Definition Documentation

ANJ_PERSISTENCE_MAGIC_MAX_SIZE

#define ANJ_PERSISTENCE_MAGIC_MAX_SIZE   16

Maximum number of bytes accepted by anj_persistence_magic() as the “magic” tag used to identify a blob format/version.

Typedef Documentation

anj_persistence_read_cb_t

typedef int anj_persistence_read_cb_t(void *ctx, void *buf, size_t size)

Read callback type. Implementations must read exactly size bytes into buf.

Parameters

	ctx	User context provided at context creation.
[out]	buf	Destination buffer.
	size	Number of bytes to read.

Returns

0 on success, negative value on error.

anj_persistence_write_cb_t

typedef int anj_persistence_write_cb_t(void *ctx, const void *buf, size_t size)

Write callback type. Implementations must write exactly size bytes from buf.

Parameters

ctx	User context provided at context creation.
buf	Source buffer.
size	Number of bytes to write.

Returns

0 on success, negative value on error.

Enumeration Type Documentation

anj_persistence_direction_t

enum anj_persistence_direction_t

Persistence direction.

Enumerator
ANJ_PERSISTENCE_STORE	Store data to the underlying medium using the write callback.
ANJ_PERSISTENCE_RESTORE	Restore data from the underlying medium using the read callback.

Function Documentation

anj_persistence_bool()

static int anj_persistence_bool ( const anj_persistence_context_t *  ctx, bool *  inout_value  )

inlinestatic

Stores/restores a boolean value.

anj_persistence_bytes()

int anj_persistence_bytes	(	const anj_persistence_context_t *	ctx,
		void *	inout_buffer,
		size_t	buffer_size
	)

Stores or restores a fixed-size byte buffer.

• In STORE mode: writes exactly buffer_size bytes from inout_buffer.
• In RESTORE mode: reads exactly buffer_size bytes into inout_buffer.

Parameters

	ctx	Persistence context.
[in,out]	inout_buffer	Buffer to write or fill.
	buffer_size	Number of bytes to transfer.

Returns

0 on success, negative value on error.

anj_persistence_direction()

static anj_persistence_direction_t anj_persistence_direction ( const anj_persistence_context_t *  ctx )

inlinestatic

Returns the direction of the persistence context.

anj_persistence_i16()

static int anj_persistence_i16 ( const anj_persistence_context_t *  ctx, int16_t *  inout_value  )

inlinestatic

Stores/restores a signed 16-bit value.

anj_persistence_i32()

static int anj_persistence_i32 ( const anj_persistence_context_t *  ctx, int32_t *  inout_value  )

inlinestatic

Stores/restores a signed 32-bit value.

anj_persistence_i64()

static int anj_persistence_i64 ( const anj_persistence_context_t *  ctx, int64_t *  inout_value  )

inlinestatic

Stores/restores a signed 64-bit value.

anj_persistence_i8()

static int anj_persistence_i8 ( const anj_persistence_context_t *  ctx, int8_t *  inout_value  )

inlinestatic

Stores/restores a signed 8-bit value.

anj_persistence_magic()

int anj_persistence_magic	(	const anj_persistence_context_t *	ctx,
		const void *	magic,
		size_t	magic_size
	)

Writes or verifies a “magic” tag.

• In STORE mode: writes magic of size magic_size.
• In RESTORE mode: reads magic_size bytes and verifies they are identical to magic.

Typical use is to guard persisted blobs with a short prefix describing the expected format/version.

Parameters

ctx	Persistence context.
magic	Pointer to expected/actual magic bytes.
magic_size	Number of bytes (<= ANJ_PERSISTENCE_MAGIC_MAX_SIZE).

Returns

0 on success, negative value on error or mismatch (RESTORE).

anj_persistence_restore_context_create()

anj_persistence_context_t anj_persistence_restore_context_create	(	anj_persistence_read_cb_t *	read_cb,
		void *	ctx
	)

Creates a persistence context for restoring data.

Parameters

read_cb	Callback to use for reading data.
ctx	User context passed to the read callback.

Returns

Persistence context.

anj_persistence_store_context_create()

anj_persistence_context_t anj_persistence_store_context_create	(	anj_persistence_write_cb_t *	write_cb,
		void *	ctx
	)

Creates a persistence context for storing data.

Warning

The persistence format is not guaranteed to be portable across architectures, compilers, or compiler versions. Moving persistence files between different systems may result in undefined behavior (e.g., due to endianness or ABI differences).

Parameters

write_cb	Callback to use for writing data.
ctx	User context passed to the write callback.

Returns

Persistence context.

anj_persistence_string()

int anj_persistence_string	(	const anj_persistence_context_t *	ctx,
		char *	inout_str,
		size_t	out_max_size
	)

Stores or restores a NUL-terminated string.

• In STORE mode: writes the string pointed to by inout_str excluding the terminating NUL byte, and its length as a 64-bit unsigned integer.
• In RESTORE mode: reads a NUL-terminated string into inout_str, writing at most out_max_size bytes (including the terminator). The result is guaranteed to be NUL-terminated if the call succeeds.

Parameters

	ctx	Persistence context.
[in,out]	inout_str	String to write or destination buffer.
	out_max_size	Size of inout_str (RESTORE). Ignored in STORE.

Returns

0 on success, negative value on error.

anj_persistence_u16()

static int anj_persistence_u16 ( const anj_persistence_context_t *  ctx, uint16_t *  inout_value  )

inlinestatic

Stores/restores an unsigned 16-bit value.

anj_persistence_u32()

static int anj_persistence_u32 ( const anj_persistence_context_t *  ctx, uint32_t *  inout_value  )

inlinestatic

Stores/restores an unsigned 32-bit value.

anj_persistence_u64()

static int anj_persistence_u64 ( const anj_persistence_context_t *  ctx, uint64_t *  inout_value  )

inlinestatic

Stores/restores an unsigned 64-bit value.

anj_persistence_u8()

static int anj_persistence_u8 ( const anj_persistence_context_t *  ctx, uint8_t *  inout_value  )

inlinestatic

Stores/restores an unsigned 8-bit value.