From eb1e015e877ff5135a3371bb81904d139d623018 Mon Sep 17 00:00:00 2001
From: Thomas White <taw27@cam.ac.uk>
Date: Sun, 23 Nov 2008 21:17:43 +0000
Subject: Attempt to use non-blocking I/O for accelerometers

---
 src/accelerometers.c | 57 ++++++++++++++++++++++++++--------------------------
 src/types.h          |  2 +-
 2 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/src/accelerometers.c b/src/accelerometers.c
index 3440fae..c68fa57 100644
--- a/src/accelerometers.c
+++ b/src/accelerometers.c
@@ -30,6 +30,11 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <time.h>
 
 #include "types.h"
 #include "audio.h"
@@ -63,8 +68,8 @@ AccelHandle *accelerometer_open() {
 	accel->type = ACCEL_UNKNOWN;
 	
 	/* Determine accelerometer type */
-	accel->fh = fopen("/dev/input/event3", "rb");
-	if ( accel->fh != NULL ) {
+	accel->fd = open("/dev/input/event3", O_RDONLY, O_NONBLOCK);
+	if ( accel->fd != -1 ) {
 		accel->type = ACCEL_FREERUNNER;
 		printf("Neo Freerunner detected\n");
 		return accel;
@@ -79,38 +84,34 @@ AccelHandle *accelerometer_open() {
 
 void accelerometer_update_freerunner(AccelHandle *accel) {
 
-	if ( accel->fh != NULL ) {
+	struct input_event ev;
+	size_t rval;
 	
-		struct input_event ev;
-		size_t rval;
-		
-		rval = fread(&ev, sizeof(struct input_event), 1, accel->fh);
-		if ( rval != 1 ) {
-			fprintf(stderr, "Couldn't read accelerometer data");
-			return;
-		}
+	rval = read(accel->fd, &ev, sizeof(ev));
+	if ( rval != sizeof(ev) ) {
+		fprintf(stderr, "Couldn't read accelerometer data");
+		return;
+	}
 	
-		if ( ev.type == EV_REL ) {
-			if ( ev.code == REL_X ) {
-				accel->lx = ev.value;
-			}
-			if ( ev.code == REL_Y ) {
-				accel->ly = ev.value;
-			}
-			if ( ev.code == REL_Z ) {
-				accel->lz = ev.value;
-			}
+	if ( ev.type == EV_REL ) {
+		if ( ev.code == REL_X ) {
+			accel->lx = ev.value;
 		}
-	
-		if ( ev.type == EV_SYN ) {
-			if ( ev.code == SYN_REPORT ) {
-				accel->x = accel->lx;
-				accel->y = accel->ly;
-				accel->z = accel->lz;
-			}
+		if ( ev.code == REL_Y ) {
+			accel->ly = ev.value;
+		}
+		if ( ev.code == REL_Z ) {
+			accel->lz = ev.value;
 		}
 	}
 
+	if ( ev.type == EV_SYN ) {
+		if ( ev.code == SYN_REPORT ) {
+			accel->x = accel->lx;
+			accel->y = accel->ly;
+			accel->z = accel->lz;
+		}
+	}
 
 }
 
diff --git a/src/types.h b/src/types.h
index 2ec6aac..89ff7f4 100644
--- a/src/types.h
+++ b/src/types.h
@@ -37,7 +37,7 @@ typedef enum {
 
 typedef struct {
 
-	FILE		*fh;
+	int		fd;
 	
 	AccelType	type;
 	
-- 
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