tlv.h File Reference

Library to encode/decode buffers in TLV (Type Length Value) format. More...

Detailed Description

Library to encode/decode buffers in TLV (Type Length Value) format.

Copyright

Wirepas Oy 2019

Definition in file tlv.h.

Go to the source code of this file.

Functions
void	Tlv_init (tlv_record *rcd, uint8_t *buffer, uint8_t length)
	Initialize a TLV record. More...
tlv_res_e	Tlv_Decode_getNextItem (tlv_record *rcd, tlv_item_t *item)
	Decode the next tlv_item in the tlv_record passed in parameter. More...
tlv_res_e	Tlv_Encode_addItem (tlv_record *rcd, tlv_item_t *item)
	Add a TLV item to the buffer contained in the TLV record. More...
int	Tlv_Encode_getBufferSize (tlv_record *rcd)
	Returns the size of the generated buffer by successive calls to Tlv_Encode_addItem. More...

Data Structures
struct	tlv_item_t
	Structure describing a Type Length Value item. More...
struct	tlv_record
	This structure holds the buffer containing TLV items and data to manage it, max. buffer size and current index. More...

Enumerations
enum	tlv_res_e { TLV_RES_OK, TLV_RES_ERROR, TLV_RES_END }
	List of return codes. More...

Function Documentation

Tlv_Decode_getNextItem()

tlv_res_e Tlv_Decode_getNextItem	(	tlv_record *	rcd,
		tlv_item_t *	item
	)

Decode the next tlv_item in the tlv_record passed in parameter.

Parameters

[in]	rcd	Pointer to a tlv_record structure to decode items from.
[in]	item	Pointer to a tlv_item. Updated by the call if return code is TLV_RES_OK

Returns

TLV_RES_OK if OK, see tlv_res_e otherwise.

Tlv_Encode_addItem()

tlv_res_e Tlv_Encode_addItem	(	tlv_record *	rcd,
		tlv_item_t *	item
	)

Add a TLV item to the buffer contained in the TLV record.

Parameters

[in]	rcd	Pointer to a tlv_record structure
[in]	item	Pointer to a tlv_item to add in the TLV record

Returns

TLV_RES_OK if OK or TLV_RES_ERROR if the buffer is to small to fit the new item.

Tlv_Encode_getBufferSize()

int Tlv_Encode_getBufferSize

(

tlv_record *

rcd

)

Returns the size of the generated buffer by successive calls to Tlv_Encode_addItem.

Parameters

[in]

rcd

Pointer to a tlv_record structure.

Returns

Total size of the buffer in bytes.

Tlv_init()

void Tlv_init	(	tlv_record *	rcd,
		uint8_t *	buffer,
		uint8_t	length
	)

Initialize a TLV record.

Parameters

[in]	rcd	Pointer to the tlv_record structure to initialize.
[in]	buffer	Buffer used by the tlv_record.
[in]	length	Size in bytes of the buffer.

Note

This funtion must be used before using the Tlv_Decode_getNextItem or Tlv_Encode_addItem functions.

---

Data Structure Documentation

tlv_item_t

struct tlv_item_t

Structure describing a Type Length Value item.

Definition at line 25 of file tlv.h.

Data Fields
uint8_t	length	Length of the value buffer.
uint16_t	type	Type of the TLV item.
uint8_t *	value	Pointer to the buffer containing the value

tlv_record

struct tlv_record

This structure holds the buffer containing TLV items and data to manage it, max. buffer size and current index.

Definition at line 36 of file tlv.h.

Data Fields
uint8_t *	buffer	Pointer to a buffer containing TLV Items.
uint8_t	index	Current encode/decode index in the buffer.
uint8_t	length	Length of the buffer.

Enumeration Type Documentation

tlv_res_e

enum tlv_res_e

List of return codes.

Enumerator
TLV_RES_OK	Successfully decoded one TLV item from the buffer.
TLV_RES_ERROR	Decode error, item is too long or lenth field is 0.
TLV_RES_END	End of buffer, nothing to decode.

Definition at line 14 of file tlv.h.

{
    TLV_RES_OK,    
    TLV_RES_ERROR, 
    TLV_RES_END,   
} tlv_res_e;