hdlc_sync.h File Reference

#include <stdbool.h>
#include "hdlc_common.h"
#include "system/error.h"

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Data Structures
struct	HDLC_SYNC_ACCUMULATOR_T
	Accumulator and state for HDLC bit-offset synchronization. More...

Macros
#define	RX_HDLC_SYNC_MAX_BUFFER_SIZE   8192
	Maximum raw RX bytes retained in the HDLC sync accumulator.
#define	HDLC_SYNC_DEFAULT_SYNC_BYTE   HDLC_FLAG_BYTE
	Default sync byte used for HDLC framing.

Enumerations
enum	HDLC_SYNC_STATE_T { HDLC_SYNC_STATE_HUNTING , HDLC_SYNC_STATE_SYNCING , HDLC_SYNC_STATE_SYNCED }
	HDLC synchronizer state machine states. More...

Functions
void	hdlc_sync_acc_init (HDLC_SYNC_ACCUMULATOR_T *accumulator, uint8_t sync_byte)
	Initialize HDLC sync accumulator state.
bool	hdlc_sync_acc_process_byte (HDLC_SYNC_ACCUMULATOR_T *accumulator, uint8_t byte)
	Append one received raw byte to the accumulator.
e2s_error_t	hdlc_sync_acc_poll (HDLC_SYNC_ACCUMULATOR_T *accumulator, HDLC_FRAME_T *out_frame)
	Poll accumulator for an aligned HDLC frame candidate.
void	hdlc_sync_acc_consume_candidate (HDLC_SYNC_ACCUMULATOR_T *accumulator, bool accept)
	Consume current candidate and advance accumulator window.

Macro Definition Documentation

HDLC_SYNC_DEFAULT_SYNC_BYTE

#define HDLC_SYNC_DEFAULT_SYNC_BYTE   HDLC_FLAG_BYTE

Default sync byte used for HDLC framing.

Definition at line 35 of file hdlc_sync.h.

RX_HDLC_SYNC_MAX_BUFFER_SIZE

#define RX_HDLC_SYNC_MAX_BUFFER_SIZE   8192

Maximum raw RX bytes retained in the HDLC sync accumulator.

Definition at line 30 of file hdlc_sync.h.

Enumeration Type Documentation

HDLC_SYNC_STATE_T

enum HDLC_SYNC_STATE_T

HDLC synchronizer state machine states.

Enumerator
HDLC_SYNC_STATE_HUNTING	Searching for first sync/flag pattern.
HDLC_SYNC_STATE_SYNCING	Sync found, building candidate with known bit offset.
HDLC_SYNC_STATE_SYNCED	Actively consuming aligned bytes until closing flag.

Definition at line 40 of file hdlc_sync.h.

Function Documentation

hdlc_sync_acc_consume_candidate()

void hdlc_sync_acc_consume_candidate	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		bool	accept
	)

Consume current candidate and advance accumulator window.

Parameters

accumulator	Accumulator instance.
accept	Acceptance hint for candidate handling.

Definition at line 622 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::candidate_end, HDLC_SYNC_ACCUMULATOR_T::candidate_start, HDLC_SYNC_ACCUMULATOR_T::candidate_valid, HDLC_SYNC_ACCUMULATOR_T::consume_count, HDLC_SYNC_ACCUMULATOR_T::hardcap_drop_bytes, HDLC_SYNC_ACCUMULATOR_T::hardcap_drop_events, hdlc_sync_drop_prefix(), hdlc_sync_reset_hunting_state(), HDLC_SYNC_ACCUMULATOR_T::position, HDLC_SYNC_ACCUMULATOR_T::processed, and RX_HDLC_SYNC_MAX_BUFFER_SIZE.

Referenced by decode_hdlc_to_udp_tx().

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hdlc_sync_acc_init()

void hdlc_sync_acc_init	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		uint8_t	sync_byte
	)

Initialize HDLC sync accumulator state.

Parameters

accumulator	Accumulator instance.
sync_byte	Sync/flag byte to detect.

Definition at line 507 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::align_shift_right, HDLC_SYNC_ACCUMULATOR_T::bit_offset, HDLC_SYNC_ACCUMULATOR_T::candidate_end, HDLC_SYNC_ACCUMULATOR_T::candidate_start, HDLC_SYNC_ACCUMULATOR_T::candidate_valid, HDLC_SYNC_ACCUMULATOR_T::consume_count, HDLC_SYNC_ACCUMULATOR_T::frame_ready_count, HDLC_SYNC_ACCUMULATOR_T::hardcap_drop_bytes, HDLC_SYNC_ACCUMULATOR_T::hardcap_drop_events, HDLC_SYNC_STATE_HUNTING, HDLC_SYNC_ACCUMULATOR_T::lookahead_wait_synced, HDLC_SYNC_ACCUMULATOR_T::lookahead_wait_syncing, HDLC_SYNC_ACCUMULATOR_T::position, HDLC_SYNC_ACCUMULATOR_T::processed, HDLC_SYNC_ACCUMULATOR_T::state, and HDLC_SYNC_ACCUMULATOR_T::sync_byte.

Referenced by decode_hdlc_to_udp_tx(), drain_hdlc_frames_to_udp(), event_dispatch(), init_app(), poll_hdlc_idle_timeout(), and poll_hdlc_no_progress().

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hdlc_sync_acc_poll()

e2s_error_t hdlc_sync_acc_poll	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		HDLC_FRAME_T *	out_frame
	)

Poll accumulator for an aligned HDLC frame candidate.

Parameters

accumulator	Accumulator instance.
out_frame	Output aligned frame buffer.

Returns

E2S_ERR_HDLC_ACC_FRAME_READY when a candidate is available, otherwise status code.

Definition at line 549 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::bit_offset, HDLC_FRAME_T::capacity, E2S_ERR_HDLC_ACC_FRAME_READY, E2S_OK, hdlc_sync_finalize_poll_no_frame(), HDLC_SYNC_POLL_STEP_ERROR, HDLC_SYNC_POLL_STEP_FRAME_READY, HDLC_SYNC_POLL_STEP_PROGRESS, HDLC_SYNC_POLL_STEP_STOP, HDLC_SYNC_STATE_HUNTING, HDLC_SYNC_STATE_SYNCED, HDLC_SYNC_STATE_SYNCING, hdlc_sync_step_hunting(), hdlc_sync_step_synced(), hdlc_sync_step_syncing(), HDLC_FRAME_T::payload, HDLC_SYNC_ACCUMULATOR_T::position, HDLC_SYNC_ACCUMULATOR_T::processed, and HDLC_SYNC_ACCUMULATOR_T::state.

Referenced by drain_hdlc_frames_to_udp().

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hdlc_sync_acc_process_byte()

bool hdlc_sync_acc_process_byte	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		uint8_t	byte
	)

Append one received raw byte to the accumulator.

Parameters

accumulator	Accumulator instance.
byte	Received raw byte.

Returns

true if appended, false if buffer full or invalid args.

Definition at line 527 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::buffer, HDLC_SYNC_ACCUMULATOR_T::position, and RX_HDLC_SYNC_MAX_BUFFER_SIZE.

Referenced by drain_rx_until_empty().

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