+++ /dev/null
-/**
- * @file sensor.c
- * @purpose Implementation of sensor thread
- * TODO: Finalise implementation
- */
-
-
-
-#include "sensor.h"
-#include "log.h"
-#include <math.h>
-
-/**
- * Read a data value from a sensor; block until value is read
- * @param sensor_id - The ID of the sensor
- * @returns The current value of the sensor
- */
-DataPoint GetData(int sensor_id)
-{
- // switch based on the sensor_id at the moment for testing;
- // might be able to just directly access ADC from sensor_id?
- //TODO: Implement for real sensors
-
- DataPoint d;
- //TODO: Deal with time stamps properly
- static int count = 0;
- d.time = count++;
- switch (sensor_id)
- {
- case SENSOR_TEST0:
- d.value = count;
- break;
- case SENSOR_TEST1:
- d.value = (float)(rand() % 100) / 100;
- break;
- default:
- Fatal("Unknown sensor id: %d", sensor_id);
- break;
- }
- usleep(100000); // simulate delay in sensor polling
- return d;
-}
-
-
-/**
- * Destroy a sensor
- * @param s - Sensor to destroy
- */
-void Destroy(Sensor * s)
-{
- // Maybe move the binary file into long term file storage?
- fclose(s->file);
-}
-
-
-
-/**
- * Initialise a sensor
- * @param s - Sensor to initialise
- */
-void Sensor_Init(Sensor * s, int id)
-{
- s->write_index = 0;
- s->read_offset = 0;
- s->id = id;
-
- #define FILENAMESIZE BUFSIZ
- char filename[FILENAMESIZE];
- //if (s->id >= pow(10, FILENAMESIZE))
- if (false)
- {
- Fatal("Too many sensors! FILENAMESIZE is %d; increase it and recompile.", FILENAMESIZE);
- }
-
- pthread_mutex_init(&(s->mutex), NULL);
-
- sprintf(filename, "%d", s->id);
- unlink(filename); //TODO: Move old files somewhere
-
- s->file = fopen(filename, "a+b"); // open binary file
- Log(LOGDEBUG, "Initialised sensor %d; binary file is \"%s\"", id, filename);
-}
-
-
-/**
- * Run the main sensor polling loop
- * @param arg - Cast to Sensor* - Sensor that the thread will handle
- * @returns NULL (void* required to use the function with pthreads)
- */
-void * Sensor_Main(void * arg)
-{
- Sensor * s = (Sensor*)(arg);
-
- while (true) //TODO: Exit condition
- {
- // The sensor will write data to a buffer until it is full
- // Then it will open a file and dump the buffer to the end of it.
- // Rinse and repeat
-
- // The reason I've added the buffer is because locks are expensive
- // But maybe it's better to just write data straight to the file
- // I'd like to do some tests by changing SENSOR_DATABUFSIZ
-
- while (s->write_index < SENSOR_DATABUFSIZ)
- {
- s->buffer[s->write_index] = GetData(s->id);
- s->write_index += 1;
- }
-
- //Log(LOGDEBUG, "Filled buffer");
-
- // CRITICAL SECTION (no threads should be able to read/write the file at the same time)
- pthread_mutex_lock(&(s->mutex));
- fseek(s->file, 0, SEEK_END);
- int amount_written = fwrite(s->buffer, sizeof(DataPoint), SENSOR_DATABUFSIZ, s->file);
- if (amount_written != SENSOR_DATABUFSIZ)
- {
- Fatal("Wrote %d data points and expected to write %d to \"%s\" - %s", amount_written, SENSOR_DATABUFSIZ, strerror(errno));
- }
- //Log(LOGDEBUG, "Wrote %d data points for sensor %d", amount_written, s->id);
- pthread_mutex_unlock(&(s->mutex));
- // End of critical section
-
- s->write_index = 0; // reset position in buffer
-
- }
- return NULL;
-}
-
-/**
- * Fill buffer with most recent sensor data
- * @param s - Sensor to use
- * @param buffer - Buffer to fill
- * @param bufsiz - Size of buffer to fill
- * @returns The number of DataPoints actually read
- */
-int Sensor_Query(Sensor * s, DataPoint * buffer, int bufsiz)
-{
- int amount_read = 0;
- //CRITICAL SECTION (Don't access file while sensor thread is writing to it!)
- pthread_mutex_lock(&(s->mutex));
-
- fseek(s->file, -bufsiz*sizeof(DataPoint), SEEK_END);
- amount_read = fread(buffer, sizeof(DataPoint), bufsiz, s->file);
- //Log(LOGDEBUG, "Read %d data points", amount_read);
- pthread_mutex_unlock(&(s->mutex));
- return amount_read;
-}
-
-
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