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#pragma once
#include <stdint.h>
/**
* @brief allocate backlog buffer and set global backlog pointer
* @param record_amt amount of records to keep before overwriting oldest record
*/
void ws_backlog_alloc(uint16_t record_amt);
// enable struct packing
#pragma pack(push, 1)
/** @brief backlog record */
typedef struct {
uint16_t id; /**< unique record identifier, numbered sequentially */
uint8_t sens_temperature; /**< temperature reading */
uint8_t sens_humidity; /**< humidity reading */
uint8_t sens_atm_pressure; /**< atmospheric pressure reading */
} ws_s_backlog_record;
typedef struct {
uint16_t buffer_size; /**< buffer size (amount of records) */
uint16_t buffer_start; /** first record index */
uint16_t buffer_end; /** last record index */
ws_s_backlog_record records[]; /** record array */
} ws_s_backlog_database;
// disable struct packing
#pragma pack(pop)
/** @brief global record backlog database pointer */
extern ws_s_backlog_database* g_ws_backlog_database;
/**
* @brief add record to database
*
* automatically sets record.id, pushes buffer_end forwards and overwrites the
* last record if the buffer is full
*/
void ws_backlog_add_record(ws_s_backlog_record record);
/**
* there's intentionally no function to retrieve multiple records as an array,
* as this would either require
* (a) copying the selection which is not possible with the current memory
* constraints, or
* (b) giving a direct pointer, but this would cause undefined behavior at the
* ring buffer seam
*/
/** @brief get pointer to record with index `record_index` from the database */
ws_s_backlog_record* ws_backlog_get_record(uint16_t record_index);
/** @brief get pointer to last record with offset `record_offset` from the database */
ws_s_backlog_record* ws_backlog_get_last_record(uint16_t record_offset);
/** @brief return amount of valid records in database */
uint16_t ws_backlog_get_record_count();
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