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

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Macros
#define	HDLC_BITS_PER_BYTE 8U

#define	HDLC_SYNC_MIN_FRAME_SIZE_BYTES 4U

#define	HDLC_SYNC_MAX_REASONABLE_FRAME_SIZE_BYTES 2048U

#define	HDLC_SYNC_SHORT_BUFFER_SEARCH_LIMIT 64U

Enumerations
enum	HDLC_SYNC_POLL_STEP_RESULT_T { HDLC_SYNC_POLL_STEP_PROGRESS , HDLC_SYNC_POLL_STEP_STOP , HDLC_SYNC_POLL_STEP_FRAME_READY , HDLC_SYNC_POLL_STEP_ERROR }

Functions
static void	hdlc_sync_drop_prefix (HDLC_SYNC_ACCUMULATOR_T *accumulator, size_t drop_count)

static void	hdlc_sync_reset_hunting_state (HDLC_SYNC_ACCUMULATOR_T *accumulator)

static void	hdlc_sync_reject_oversized_candidate (HDLC_SYNC_ACCUMULATOR_T accumulator, HDLC_FRAME_T out_frame, size_t *scan_index)

static bool	hdlc_sync_get_aligned_byte (const HDLC_SYNC_ACCUMULATOR_T accumulator, size_t raw_index, uint8_t bit_offset, bool shift_right, uint8_t out_byte)

static bool	hdlc_sync_find_opening_candidate (const HDLC_SYNC_ACCUMULATOR_T accumulator, size_t scan_index, bool allow_left_shift, size_t out_start_index, uint8_t out_bit_pos, bool out_shift_right)

static bool	hdlc_sync_find_complete_candidate_short (const HDLC_SYNC_ACCUMULATOR_T accumulator, size_t scan_index, size_t out_start_index, uint8_t out_bit_pos, bool out_shift_right)

static HDLC_SYNC_POLL_STEP_RESULT_T	hdlc_sync_step_hunting (HDLC_SYNC_ACCUMULATOR_T accumulator, HDLC_FRAME_T out_frame, size_t *scan_index)

static HDLC_SYNC_POLL_STEP_RESULT_T	hdlc_sync_step_syncing (HDLC_SYNC_ACCUMULATOR_T accumulator, HDLC_FRAME_T out_frame, size_t scan_index, e2s_error_t out_error)

static HDLC_SYNC_POLL_STEP_RESULT_T	hdlc_sync_step_synced (HDLC_SYNC_ACCUMULATOR_T accumulator, HDLC_FRAME_T out_frame, size_t scan_index, e2s_error_t out_error)

static void	hdlc_sync_finalize_poll_no_frame (HDLC_SYNC_ACCUMULATOR_T *accumulator, size_t scan_index)

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_BITS_PER_BYTE

#define HDLC_BITS_PER_BYTE 8U

Definition at line 26 of file hdlc_sync.c.

◆ HDLC_SYNC_MAX_REASONABLE_FRAME_SIZE_BYTES

#define HDLC_SYNC_MAX_REASONABLE_FRAME_SIZE_BYTES 2048U

Definition at line 28 of file hdlc_sync.c.

◆ HDLC_SYNC_MIN_FRAME_SIZE_BYTES

#define HDLC_SYNC_MIN_FRAME_SIZE_BYTES 4U

Definition at line 27 of file hdlc_sync.c.

◆ HDLC_SYNC_SHORT_BUFFER_SEARCH_LIMIT

#define HDLC_SYNC_SHORT_BUFFER_SEARCH_LIMIT 64U

Definition at line 29 of file hdlc_sync.c.

Enumeration Type Documentation

◆ HDLC_SYNC_POLL_STEP_RESULT_T

enum HDLC_SYNC_POLL_STEP_RESULT_T

Enumerator
HDLC_SYNC_POLL_STEP_PROGRESS
HDLC_SYNC_POLL_STEP_STOP
HDLC_SYNC_POLL_STEP_FRAME_READY
HDLC_SYNC_POLL_STEP_ERROR

Definition at line 57 of file hdlc_sync.c.

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.

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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◆ hdlc_sync_drop_prefix()

static void hdlc_sync_drop_prefix	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		size_t	drop_count
	)

static

Definition at line 70 of file hdlc_sync.c.

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

Referenced by hdlc_sync_acc_consume_candidate(), hdlc_sync_finalize_poll_no_frame(), and hdlc_sync_reject_oversized_candidate().

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◆ hdlc_sync_finalize_poll_no_frame()

static void hdlc_sync_finalize_poll_no_frame	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		size_t	scan_index
	)

static

Definition at line 483 of file hdlc_sync.c.

References hdlc_sync_drop_prefix(), HDLC_SYNC_STATE_HUNTING, HDLC_SYNC_ACCUMULATOR_T::position, HDLC_SYNC_ACCUMULATOR_T::processed, and HDLC_SYNC_ACCUMULATOR_T::state.

Referenced by hdlc_sync_acc_poll().

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◆ hdlc_sync_find_complete_candidate_short()

static bool hdlc_sync_find_complete_candidate_short	(	const HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		size_t	scan_index,
		size_t *	out_start_index,
		uint8_t *	out_bit_pos,
		bool *	out_shift_right
	)

static

Definition at line 248 of file hdlc_sync.c.

References HDLC_BITS_PER_BYTE, hdlc_sync_get_aligned_byte(), HDLC_SYNC_MIN_FRAME_SIZE_BYTES, HDLC_SYNC_SHORT_BUFFER_SEARCH_LIMIT, HDLC_SYNC_ACCUMULATOR_T::position, and HDLC_SYNC_ACCUMULATOR_T::sync_byte.

Referenced by hdlc_sync_step_hunting().

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◆ hdlc_sync_find_opening_candidate()

static bool hdlc_sync_find_opening_candidate	(	const HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		size_t	scan_index,
		bool	allow_left_shift,
		size_t *	out_start_index,
		uint8_t *	out_bit_pos,
		bool *	out_shift_right
	)

static

Definition at line 177 of file hdlc_sync.c.

References HDLC_BITS_PER_BYTE, hdlc_sync_get_aligned_byte(), HDLC_SYNC_ACCUMULATOR_T::position, and HDLC_SYNC_ACCUMULATOR_T::sync_byte.

Referenced by hdlc_sync_step_hunting().

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◆ hdlc_sync_get_aligned_byte()

static bool hdlc_sync_get_aligned_byte	(	const HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		size_t	raw_index,
		uint8_t	bit_offset,
		bool	shift_right,
		uint8_t *	out_byte
	)

static

Definition at line 136 of file hdlc_sync.c.

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

Referenced by hdlc_sync_find_complete_candidate_short(), hdlc_sync_find_opening_candidate(), hdlc_sync_step_synced(), and hdlc_sync_step_syncing().

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◆ hdlc_sync_reject_oversized_candidate()

static void hdlc_sync_reject_oversized_candidate	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		HDLC_FRAME_T *	out_frame,
		size_t *	scan_index
	)

static

Definition at line 108 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::candidate_start, hdlc_sync_drop_prefix(), hdlc_sync_reset_hunting_state(), HDLC_FRAME_T::length, and HDLC_SYNC_ACCUMULATOR_T::position.

Referenced by hdlc_sync_step_synced(), and hdlc_sync_step_syncing().

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◆ hdlc_sync_reset_hunting_state()

static void hdlc_sync_reset_hunting_state ( HDLC_SYNC_ACCUMULATOR_T * accumulator )

static

Definition at line 90 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_STATE_HUNTING, HDLC_SYNC_ACCUMULATOR_T::processed, and HDLC_SYNC_ACCUMULATOR_T::state.

Referenced by hdlc_sync_acc_consume_candidate(), and hdlc_sync_reject_oversized_candidate().

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◆ hdlc_sync_step_hunting()

static HDLC_SYNC_POLL_STEP_RESULT_T hdlc_sync_step_hunting	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		HDLC_FRAME_T *	out_frame,
		size_t *	scan_index
	)

static

Definition at line 343 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::align_shift_right, HDLC_SYNC_ACCUMULATOR_T::bit_offset, HDLC_SYNC_ACCUMULATOR_T::candidate_start, HDLC_SYNC_ACCUMULATOR_T::candidate_valid, hdlc_sync_find_complete_candidate_short(), hdlc_sync_find_opening_candidate(), HDLC_SYNC_POLL_STEP_PROGRESS, HDLC_SYNC_POLL_STEP_STOP, HDLC_SYNC_STATE_SYNCING, HDLC_FRAME_T::length, HDLC_FRAME_T::payload, HDLC_SYNC_ACCUMULATOR_T::position, HDLC_SYNC_ACCUMULATOR_T::state, and HDLC_SYNC_ACCUMULATOR_T::sync_byte.

Referenced by hdlc_sync_acc_poll().

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◆ hdlc_sync_step_synced()

static HDLC_SYNC_POLL_STEP_RESULT_T hdlc_sync_step_synced	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		HDLC_FRAME_T *	out_frame,
		size_t *	scan_index,
		e2s_error_t *	out_error
	)

static

Definition at line 420 of file hdlc_sync.c.

Referenced by hdlc_sync_acc_poll().

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◆ hdlc_sync_step_syncing()

static HDLC_SYNC_POLL_STEP_RESULT_T hdlc_sync_step_syncing	(	HDLC_SYNC_ACCUMULATOR_T *	accumulator,
		HDLC_FRAME_T *	out_frame,
		size_t *	scan_index,
		e2s_error_t *	out_error
	)

static

Definition at line 379 of file hdlc_sync.c.

References HDLC_SYNC_ACCUMULATOR_T::align_shift_right, HDLC_SYNC_ACCUMULATOR_T::bit_offset, HDLC_FRAME_T::capacity, E2S_ERR_HDLC_DECODE_PAYLOAD_TOO_LONG, hdlc_sync_get_aligned_byte(), HDLC_SYNC_MAX_REASONABLE_FRAME_SIZE_BYTES, HDLC_SYNC_POLL_STEP_ERROR, HDLC_SYNC_POLL_STEP_PROGRESS, HDLC_SYNC_POLL_STEP_STOP, hdlc_sync_reject_oversized_candidate(), HDLC_SYNC_STATE_HUNTING, HDLC_SYNC_STATE_SYNCED, HDLC_FRAME_T::length, HDLC_SYNC_ACCUMULATOR_T::lookahead_wait_syncing, HDLC_FRAME_T::payload, and HDLC_SYNC_ACCUMULATOR_T::state.

Referenced by hdlc_sync_acc_poll().

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Macros

Enumerations

Functions

Macro Definition Documentation

◆ HDLC_BITS_PER_BYTE

◆ HDLC_SYNC_MAX_REASONABLE_FRAME_SIZE_BYTES

◆ HDLC_SYNC_MIN_FRAME_SIZE_BYTES

◆ HDLC_SYNC_SHORT_BUFFER_SEARCH_LIMIT

Enumeration Type Documentation

◆ HDLC_SYNC_POLL_STEP_RESULT_T

Function Documentation

◆ hdlc_sync_acc_consume_candidate()

◆ hdlc_sync_acc_init()

◆ hdlc_sync_acc_poll()

◆ hdlc_sync_acc_process_byte()

◆ hdlc_sync_drop_prefix()

◆ hdlc_sync_finalize_poll_no_frame()

◆ hdlc_sync_find_complete_candidate_short()

◆ hdlc_sync_find_opening_candidate()

◆ hdlc_sync_get_aligned_byte()

◆ hdlc_sync_reject_oversized_candidate()

◆ hdlc_sync_reset_hunting_state()

◆ hdlc_sync_step_hunting()

◆ hdlc_sync_step_synced()

◆ hdlc_sync_step_syncing()