From bcb64b3297b0366331de7aed12f1fdf7165ac0d6 Mon Sep 17 00:00:00 2001
From: Jef Driesen <jefdriesen@users.sourceforge.net>
Date: Fri, 22 Sep 2017 22:16:56 +0200
Subject: [PATCH] Workaround for a Windows libusb issue

When libusb uses the Windows HID api internally, it does automatically
prepend a zero report ID to the data for devices which support only a
single report. But apparently it also returns a size of one byte extra!
As a workaround, the number of bytes is limited to the actual size.

See commit c9ed92d3f55c259931527a27d018eb5791a176dd for a similar issue
in the hidapi library.
---
 src/usbhid.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/usbhid.c b/src/usbhid.c
index b697f47..38931b8 100644
--- a/src/usbhid.c
+++ b/src/usbhid.c
@@ -45,6 +45,7 @@
 #include "usbhid.h"
 #include "common-private.h"
 #include "context-private.h"
+#include "platform.h"
 
 struct dc_usbhid_t {
 	/* Library context. */
@@ -432,15 +433,16 @@ dc_usbhid_write (dc_usbhid_t *usbhid, const void *data, size_t size, size_t *act
 		nbytes = 0;
 		goto out;
 	}
-
-#ifdef _WIN32
-	if (nbytes > size) {
-		nbytes = size;
-	}
-#endif
 #endif
 
 out:
+#ifdef _WIN32
+	if (nbytes > size) {
+		WARNING (usbhid->context, "Number of bytes exceeds the buffer size (" DC_PRINTF_SIZE " > " DC_PRINTF_SIZE ")!", nbytes, size);
+		nbytes = size;
+	}
+#endif
+
 	HEXDUMP (usbhid->context, DC_LOGLEVEL_INFO, "Write", (unsigned char *) data, nbytes);
 
 out_invalidargs: