libaltos: Use case-insensitive compare when matching BT MACs

We use the BT MAC vendor portion to figure out which port to connect
to as that is simpler and takes less network traffic than actually
doing discovery. However, on Windows, we were generating the address
in lower case and comparing against upper case vendors, which didn't
work out too well.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 23 insertions, 8 deletions

diff --git a/libaltos/libaltos_common.c b/libaltos/libaltos_common.c
index f577de02..713a775c 100644
--- a/libaltos/libaltos_common.c
+++ b/libaltos/libaltos_common.c
@@ -76,24 +76,39 @@ altos_putchar(struct altos_file *file, char c)
 }
 
 struct bt_vendor_map {
-	char	vendor[10];
-	int	port;
+	const char	vendor[10];
+	int		port;
 };
 
 static const struct bt_vendor_map altos_bt_vendor_map[] = {
 	{ .vendor = "00:12:6f:", 1 },	/* Rayson */
-	{ .vendor = "8C:DE:52:", 6 },	/* ISSC */
-	{ .vendor = "D8:80:39:", 6 },	/* Microchip */
+	{ .vendor = "8c:de:52:", 6 },	/* ISSC */
+	{ .vendor = "d8:80:39:", 6 },	/* Microchip */
 };
 
 #define NUM_BT_VENDOR_MAP	(sizeof altos_bt_vendor_map / sizeof altos_bt_vendor_map[0])
 #define BT_PORT_DEFAULT		1
 
+static inline int
+ao_tolower(int c) {
+	if ('A' <= c && c <= 'Z')
+		return c + 'a' - 'A';
+	return c;
+}
+
 int altos_bt_port(struct altos_bt_device *device) {
-	unsigned i;
-	for (i = 0; i < NUM_BT_VENDOR_MAP; i++)
-		if (strncmp (device->addr, altos_bt_vendor_map[i].vendor, strlen(altos_bt_vendor_map[i].vendor)) == 0)
-			return altos_bt_vendor_map[i].port;
+	unsigned i, j;
+	for (i = 0; i < NUM_BT_VENDOR_MAP; i++) {
+		const char *vendor = altos_bt_vendor_map[i].vendor;
+		for (j = 0; ; j++) {
+			if (vendor[j] == '\0')
+				return altos_bt_vendor_map[i].port;
+			if (device->addr[j] == '\0')
+				break;
+			if (ao_tolower(device->addr[j]) != vendor[j])
+				break;
+		}
+	}
 	return BT_PORT_DEFAULT;
 }