From 8f8a086eee160c548751336e8195f588a31f5ac1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Fri, 15 Apr 2016 11:59:14 +0200
Subject: [PATCH] use LENGTH instead of sizeof for array indexes

---
 lib/usb_cdcacm.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/lib/usb_cdcacm.c b/lib/usb_cdcacm.c
index 4d01ed2..9314fc0 100644
--- a/lib/usb_cdcacm.c
+++ b/lib/usb_cdcacm.c
@@ -34,6 +34,7 @@
 #include <libopencm3/usb/cdc.h> // USB CDC library
 #include <libopencm3/cm3/sync.h> // synchronisation utilities
 
+#include "global.h" // global utilities
 #include "usb_cdcacm.h" // USB CDC ACM header and definitions
 
 /** @brief USB CDC ACM device descriptor
@@ -257,17 +258,17 @@ static int cdcacm_control_request(usbd_device *usbd_dev, struct usb_setup_data *
 			 * even though it's optional in the CDC spec, and we don't
 			 * advertise it in the ACM functional descriptor.
 			 */
-			char local_buf[10];
-			struct usb_cdc_notification *notif = (void *)local_buf;
+			uint8_t reply[10] = {0};
+			struct usb_cdc_notification *notif = (void *)reply;
 			/* we echo signals back to host as notification. */
 			notif->bmRequestType = 0xA1;
 			notif->bNotification = USB_CDC_NOTIFY_SERIAL_STATE;
 			notif->wValue = 0;
 			notif->wIndex = 0;
 			notif->wLength = 2;
-			local_buf[8] = req->wValue & 3;
-			local_buf[9] = 0;
-			usbd_ep_write_packet(usbd_dev, 0x83, local_buf, 10);
+			reply[8] = req->wValue & 3;
+			reply[9] = 0;
+			usbd_ep_write_packet(usbd_dev, 0x83, reply, LENGTH(reply));
 			break;
 		case USB_CDC_REQ_SET_LINE_CODING:
 			// ignore if length is wrong
@@ -306,8 +307,8 @@ static void cdcacm_data_rx_cb(usbd_device *usbd_dev, uint8_t ep)
 	/* receive data */
 	usb_length = usbd_ep_read_packet(usbd_dev, 0x01, usb_data, sizeof(usb_data));
 	if (usb_length) { // copy received data
-		for (uint16_t i=0; i<usb_length && rx_used<sizeof(rx_buffer); i++) { // only until buffer is full
-			rx_buffer[(rx_i+rx_used)%sizeof(rx_buffer)] = usb_data[i]; // put character in buffer
+		for (uint16_t i=0; i<usb_length && rx_used<LENGTH(rx_buffer); i++) { // only until buffer is full
+			rx_buffer[(rx_i+rx_used)%LENGTH(rx_buffer)] = usb_data[i]; // put character in buffer
 			rx_used++; // update used buffer
 		}
 		cdcacm_received = rx_used; // update available data
@@ -328,9 +329,9 @@ static void cdcacm_data_tx_cb(usbd_device *usbd_dev, uint8_t ep)
 	}
 	if (mutex_trylock(&tx_lock)) { // try to get lock
 		uint8_t usb_length = (tx_used > 64 ? 64 : tx_used); // length of data to be transmitted (respect max packet size)
-		usb_length = (usb_length > (sizeof(tx_buffer)-tx_i) ? sizeof(tx_buffer)-tx_i : usb_length); // since here we use the source array not as ring buffer, only go up to the end
+		usb_length = (usb_length > (LENGTH(tx_buffer)-tx_i) ? LENGTH(tx_buffer)-tx_i : usb_length); // since here we use the source array not as ring buffer, only go up to the end
 		while (usb_length != usbd_ep_write_packet(usb_device, 0x82, (void*)(&tx_buffer[tx_i]), usb_length)); // ensure data is written into transmit buffer
-		tx_i = (tx_i+usb_length)%sizeof(tx_buffer); // update location on buffer
+		tx_i = (tx_i+usb_length)%LENGTH(tx_buffer); // update location on buffer
 		tx_used -= usb_length; // update used size
 		mutex_unlock(&tx_lock); // release lock
 	} else {
@@ -382,7 +383,7 @@ char cdcacm_getchar(void)
 		__WFI(); // sleep until interrupt (not sure if it's a good idea here)
 	}
 	char to_return = rx_buffer[rx_i]; // get the next available character
-	rx_i = (rx_i+1)%sizeof(rx_buffer); // update used buffer
+	rx_i = (rx_i+1)%LENGTH(rx_buffer); // update used buffer
 	rx_used--; // update used buffer
 	cdcacm_received = rx_used; // update available data
 	return to_return;
@@ -394,12 +395,12 @@ void cdcacm_putchar(char c)
 		return;
 	}
 	mutex_lock(&tx_lock); // get lock to prevent race condition
-	if (tx_used<sizeof(tx_buffer)) { // buffer not full
-		tx_buffer[(tx_i+tx_used)%sizeof(tx_buffer)] = c; // put character in buffer
+	if (tx_used<LENGTH(tx_buffer)) { // buffer not full
+		tx_buffer[(tx_i+tx_used)%LENGTH(tx_buffer)] = c; // put character in buffer
 		tx_used++; // update used buffer
 	} else { // buffer full (might be that no terminal is connected to this serial)
-		tx_i = (tx_i+1)%sizeof(tx_buffer); // shift start
-		tx_buffer[(tx_i+tx_used)%sizeof(tx_buffer)] = c; // overwrite old data
+		tx_i = (tx_i+1)%LENGTH(tx_buffer); // shift start
+		tx_buffer[(tx_i+tx_used)%LENGTH(tx_buffer)] = c; // overwrite old data
 	}
 	mutex_unlock(&tx_lock); // release lock
 	usbd_ep_write_packet(usb_device, 0x82, NULL, 0); // trigger tx callback