/**
* @file sensor.c
- * @purpose Implementation of sensor thread
+ * @brief Implementation of sensor thread
* TODO: Finalise implementation
*/
-
#include "common.h"
#include "sensor.h"
+#include "options.h"
#include <math.h>
/** Array of sensors, initialised by Sensor_Init **/
static Sensor g_sensors[NUMSENSORS]; //global to this file
-
+static const char * g_sensor_names[] = {"analog_test0", "analog_test1", "digital_test0", "digital_test1"};
/**
* Read a data value from a sensor; block until value is read
* @param sensor_id - The ID of the sensor
* @param d - DataPoint to set
- * @returns NULL on error, otherwise d
+ * @returns NULL for digital sensors when data is unchanged, otherwise d
*/
DataPoint * GetData(int sensor_id, DataPoint * d)
{
//TODO: We should ensure the time is *never* allowed to change on the server if we use gettimeofday
// Another way people might think of getting the time is to count CPU cycles with clock()
// But this will not work because a) CPU clock speed may change on some devices (RPi?) and b) It counts cycles used by all threads
- gettimeofday(&(d->time_stamp), NULL);
+
+ struct timeval t;
+ gettimeofday(&t, NULL);
+ d->time_stamp = (t.tv_sec - g_options.start_time.tv_sec) + 1e-6*(t.tv_usec - g_options.start_time.tv_usec);
+
+ // Make time relative
+ //d->time_stamp.tv_sec -= g_options.start_time.tv_sec;
+ //d->time_stamp.tv_usec -= g_options.start_time.tv_usec;
switch (sensor_id)
{
- case SENSOR_TEST0:
+ case ANALOG_TEST0:
{
static int count = 0;
d->value = count++;
break;
}
- case SENSOR_TEST1:
- d->value = (float)(rand() % 100) / 100;
+ case ANALOG_TEST1:
+ d->value = (double)(rand() % 100) / 100;
+ break;
+
+ //TODO: For digital sensors, consider only updating when sensor is actually changed
+ case DIGITAL_TEST0:
+ d->value = t.tv_sec % 2;
+ break;
+ case DIGITAL_TEST1:
+ d->value = (t.tv_sec+1)%2;
break;
default:
Fatal("Unknown sensor id: %d", sensor_id);
void Init(Sensor * s, int id)
{
s->write_index = 0;
- s->read_offset = 0;
s->id = id;
#define FILENAMESIZE 3
return NULL;
}
// Bounds check
- if (id < 0 || id > NUMSENSORS)
+ if (id < 0 || id >= NUMSENSORS)
return NULL;
+
+ Log(LOGDEBUG, "Sensor \"%s\" identified", g_sensor_names[id]);
return g_sensors+id;
}
{
DataPoint buffer[SENSOR_QUERYBUFSIZ];
StatusCodes status = STATUS_OK;
+
+ enum {DEFAULT, DUMP} operation = DEFAULT;
+
const char * key; const char * value;
Sensor * sensor = NULL;
break;
}
}
+ else if (strcmp(key, "dump") == 0)
+ {
+ if (operation != DEFAULT)
+ {
+ Log(LOGERR, "Operation already specified!");
+ status = STATUS_ERROR;
+ break;
+ }
+ operation = DUMP;
+ }
else
{
Log(LOGERR, "Unknown key \"%s\" (value = %s)", key, value);
if (status == STATUS_ERROR)
{
FCGI_RejectJSON(context);
+ return;
}
- else
+
+ switch (operation)
{
-
- FCGI_BeginJSON(context, status);
- FCGI_JSONPair(key, value); // should spit back sensor ID
- //Log(LOGDEBUG, "Call Sensor_Query...");
- int amount_read = Sensor_Query(sensor, buffer, SENSOR_QUERYBUFSIZ);
- //Log(LOGDEBUG, "Read %d DataPoints", amount_read);
- //Log(LOGDEBUG, "Produce JSON response");
- FCGI_JSONKey("data");
- FCGI_JSONValue("[");
- for (int i = 0; i < amount_read; ++i)
+ case DUMP:
{
- //TODO: Consider; is it better to give both tv_sec and tv_usec to the client seperately, instead of combining here?
- //NOTE: Must always use doubles; floats get rounded!
- double time = buffer[i].time_stamp.tv_sec + 1e-6*(buffer[i].time_stamp.tv_usec);
- FCGI_JSONValue("[%f, %f]", time, buffer[i].value);
- if (i+1 < amount_read)
- FCGI_JSONValue(",");
+ FCGI_PrintRaw("Content-type: text/plain\r\n\r\n");
+ //CRITICAL SECTION
+ pthread_mutex_lock(&(sensor->mutex));
+ fseek(sensor->file, 0, SEEK_SET);
+ int amount_read = 0;
+ do
+ {
+ amount_read = fread(buffer, sizeof(DataPoint), SENSOR_QUERYBUFSIZ, sensor->file);
+ for (int i = 0; i < amount_read; ++i)
+ {
+ FCGI_PrintRaw("%f\t%f\n", buffer[i].time_stamp, buffer[i].value);
+ }
+
+ }
+ while (amount_read == SENSOR_QUERYBUFSIZ);
+ pthread_mutex_unlock(&(sensor->mutex));
+ // end critical section
+ break;
+ }
+ default:
+ {
+ FCGI_BeginJSON(context, status);
+ FCGI_JSONPair(key, value); // should spit back sensor ID
+ //Log(LOGDEBUG, "Call Sensor_Query...");
+ int amount_read = Sensor_Query(sensor, buffer, SENSOR_QUERYBUFSIZ);
+ //Log(LOGDEBUG, "Read %d DataPoints", amount_read);
+ //Log(LOGDEBUG, "Produce JSON response");
+ FCGI_JSONKey("data");
+ FCGI_JSONValue("[");
+ for (int i = 0; i < amount_read; ++i)
+ {
+ //TODO: Consider; is it better to give both tv_sec and tv_usec to the client seperately, instead of combining here?
+
+ FCGI_JSONValue("[%f, %f]", buffer[i].time_stamp, buffer[i].value);
+ if (i+1 < amount_read)
+ FCGI_JSONValue(",");
+ }
+ FCGI_JSONValue("]");
+ //Log(LOGDEBUG, "Done producing JSON response");
+ FCGI_EndJSON();
+ break;
}
- FCGI_JSONValue("]");
- //Log(LOGDEBUG, "Done producing JSON response");
- FCGI_EndJSON();
}
}