Add relative times, allow "points" param to work with "start_time"

Eg: To get a single point at a given time: http://localhost/api/sensors?id=0&start_time=5&points=1

The binary search means it will either get the closest point before or after the specified time.

Should probably make it so that FindTime will always get the same index given the same input.
Otherwise problems might arise.

Need some more argument checking?

diff --git a/server/sensor.c b/server/sensor.c
index bcf1fcf..9055409 100644 (file)
--- a/server/sensor.c
+++ b/server/sensor.c
@@ -385,7 +385,9 @@ void Sensor_Handler(FCGIContext *context, char * params)
 
        double start_time = -1;
        double end_time = -1;
+       double current_time = (now.tv_sec - g_options.start_time.tv_sec) + 1e-6*(now.tv_usec - g_options.start_time.tv_usec);
        bool seek_time = false;
+       bool points_specified = false;
        int query_size = SENSOR_QUERYBUFSIZ;
        int start_index = -1;
        int end_index = -1;
@@ -428,6 +430,7 @@ void Sensor_Handler(FCGIContext *context, char * params)
                }
                else if (strcmp(key, "points") == 0)
                {
+                       points_specified = true;
                        if (strcmp(value, "all") == 0)
                        {
                                query_size = sensor->points_written;
@@ -456,6 +459,13 @@ void Sensor_Handler(FCGIContext *context, char * params)
                                status = STATUS_ERROR;
                                break;
                        }                       
+
+                       // Treat negative values as being relative to the current time
+                       if (start_time < 0)
+                       {
+                               start_time = current_time + start_time;
+                       }
+                       start_time = floor(start_time);
                }
                else if (strcmp(key, "end_time") == 0)
                {
@@ -467,7 +477,14 @@ void Sensor_Handler(FCGIContext *context, char * params)
                                Log(LOGERR, "Require a double: %s = %s", key, value);
                                status = STATUS_ERROR;
                                break;
-                       }                       
+                       }       
+
+                       // Treat negative values as being relative to the current time
+                       if (end_time < 0)
+                       {
+                               end_time = current_time + end_time;
+                       }               
+                       end_time = ceil(end_time);
                }
                // For backward compatability:
                else if (strcmp(key, "dump") == 0)
@@ -498,13 +515,13 @@ void Sensor_Handler(FCGIContext *context, char * params)
 
        if (seek_time)
        {
-               if (end_time < 0)
+               if (end_time < 0 && !points_specified)
                        end_index = sensor->points_written;
                else
                {
                        int count = 0; DataPoint d;
                        end_index = FindTime(sensor, end_time, &count, &d);
-                       //Log(LOGDEBUG, "FindTime - Looked for %f; found [%f,%f] after %d iterations; sensor %d, position %d", end_time, d.time_stamp, d.value, count, sensor->id, end_index);
+                       Log(LOGDEBUG, "FindTime - Looked for %f; found [%f,%f] after %d iterations; sensor %d, position %d", end_time, d.time_stamp, d.value, count, sensor->id, end_index);
                }
                if (start_time < 0)
                        start_time = 0;
@@ -512,8 +529,11 @@ void Sensor_Handler(FCGIContext *context, char * params)
                {
                        int count = 0; DataPoint d;
                        start_index = FindTime(sensor, start_time, &count, &d);
-                       //Log(LOGDEBUG, "FindTime - Looked for %f; found [%f,%f] after %d iterations; sensor %d, position %d", start_time, d.time_stamp, d.value, count, sensor->id, start_index);
+                       Log(LOGDEBUG, "FindTime - Looked for %f; found [%f,%f] after %d iterations; sensor %d, position %d", start_time, d.time_stamp, d.value, count, sensor->id, start_index);
                }
+
+               if (points_specified)
+                       end_index = start_index + query_size;
        }
        else
        {