fakenect: replay index in an endless loop

When the last line has been handled then the index gets closed and any
'prev' state is reset so that the next call to freenect_process_events
will re-open the index and start again from the first frame.

Since the Kinect camera doesn't normally spontaneously stop this seems
like a more natural behaviour.

In case there is some use case that would prefer to avoid looping over
frames then the previous behaviour can be got by setting
FAKENECT_LOOP=0 (or some case variant of 'false', 'off' or 'no')

Signed-off-by: Robert Bragg <robert@impossible.com>

fakenect/fakenect.c

@@ -34,6 +34,8 @@
 #include <math.h>
 #include <unistd.h>
 #include <assert.h>
+#include <stdbool.h>
+#include <ctype.h>
 
 #define GRAVITY 9.80665
 
@@ -56,6 +58,7 @@ static void *user_video_buf = NULL;
 static int depth_running = 0;
 static int rgb_running = 0;
 static void *user_ptr = NULL;
+static bool loop_playback = true;
 
 #define MAKE_RESERVED(res, fmt) (uint32_t)(((res & 0xff) << 8) | (((fmt & 0xff))))
 #define RESERVED_TO_RESOLUTION(reserved) (freenect_resolution)((reserved >> 8) & 0xff)
@@ -157,6 +160,14 @@ static void open_index()
 	free(index_path);
 }
 
+static void close_index()
+{
+	fclose(index_fp);
+	index_fp = NULL;
+	record_prev_time = 0;
+	playback_prev_time = 0;
+}
+
 static char *skip_line(char *str)
 {
 	char *out = strchr(str, '\n');
@@ -211,8 +222,13 @@ int freenect_process_events(freenect_context *ctx)
 	double record_cur_time;
 	unsigned int timestamp, data_size;
 	char *data = NULL;
-	if (parse_line(&type, &record_cur_time, &timestamp, &data_size, &data))
-		return -1;
+	if (parse_line(&type, &record_cur_time, &timestamp, &data_size, &data)) {
+                if (loop_playback) {
+			close_index();
+			return 0;
+                } else
+		    return -1;
+	}
 	// Sleep an amount that compensates for the original and current delays
 	// playback_ is w.r.t. the current time
 	// record_ is w.r.t. the original time period during the recording
@@ -509,6 +525,21 @@ int freenect_init(freenect_context **ctx, freenect_usb_context *usb_ctx)
 		exit(1);
 	}
 
+	char *var = getenv("FAKENECT_LOOP");
+	if (var) {
+		int len = strlen(var);
+		char tmp[len + 1];
+		for (int i = 0; i < len; i++)
+			tmp[i] = tolower(var[i]);
+		tmp[len] = '\0';
+		if (strcmp(tmp, "0") == 0 ||
+		    strcmp(tmp, "false") == 0 ||
+		    strcmp(tmp, "no") == 0 ||
+		    strcmp(tmp, "off") == 0) {
+			loop_playback = false;
+		}
+	}
+
 	*ctx = fake_ctx;
 
 	read_device_info(fake_dev);