X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=server%2Fsensor.c;h=ab687afdf5ecee1c75293888ad592fcdca0925a7;hb=82a411cede82ee10a9d29dc08ca01949576ede24;hp=d1d8b9fc04bd9d06c859d8031c76f1e7abb949a5;hpb=01e621afb7cfbc4b570cac55128f5023798a9ce3;p=matches%2FMCTX3420.git

diff --git a/server/sensor.c b/server/sensor.c
index d1d8b9f..ab687af 100644
--- a/server/sensor.c
+++ b/server/sensor.c
@@ -4,14 +4,147 @@
  * 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 args - IGNORED (void* required to use the function with pthreads)
+ * @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 * args)
+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;
+}
+
+