Windows: hid_get_feature/input_report return size fix (#334)

- It appears when the numbered reports aren't used,
WinAPI returns size of the report excluding the data[0] which contains 0,
as an indication that numbered reports aren't used;
Explicity count that byte in the result.

Fixes: #328

Author: Youw

windows/hid.c

@@ -1039,33 +1039,24 @@ int HID_API_EXPORT HID_API_CALL hid_send_feature_report(hid_device *dev, const u
 	return (int) length;
 }
 
-
-int HID_API_EXPORT HID_API_CALL hid_get_feature_report(hid_device *dev, unsigned char *data, size_t length)
+static int hid_get_report(hid_device *dev, DWORD report_type, unsigned char *data, size_t length)
 {
 	BOOL res;
-#if 0
-	res = HidD_GetFeature(dev->device_handle, data, length);
-	if (!res) {
-		register_error(dev, "HidD_GetFeature");
-		return -1;
-	}
-	return 0; /* HidD_GetFeature() doesn't give us an actual length, unfortunately */
-#else
-	DWORD bytes_returned;
+	DWORD bytes_returned = 0;
 
 	OVERLAPPED ol;
 	memset(&ol, 0, sizeof(ol));
 
 	res = DeviceIoControl(dev->device_handle,
-		IOCTL_HID_GET_FEATURE,
+		report_type,
 		data, (DWORD) length,
 		data, (DWORD) length,
 		&bytes_returned, &ol);
 
 	if (!res) {
 		if (GetLastError() != ERROR_IO_PENDING) {
 			/* DeviceIoControl() failed. Return error. */
-			register_error(dev, "Send Feature Report DeviceIoControl");
+			register_error(dev, "Get Input/Feature Report DeviceIoControl");
 			return -1;
 		}
 	}
@@ -1075,56 +1066,30 @@ int HID_API_EXPORT HID_API_CALL hid_get_feature_report(hid_device *dev, unsigned
 	res = GetOverlappedResult(dev->device_handle, &ol, &bytes_returned, TRUE/*wait*/);
 	if (!res) {
 		/* The operation failed. */
-		register_error(dev, "Send Feature Report GetOverLappedResult");
+		register_error(dev, "Get Input/Feature Report GetOverLappedResult");
 		return -1;
 	}
 
+	/* When numbered reports aren't used,
+	   bytes_returned seem to include only what is actually received from the device
+	   (not including the first byte with 0, as an indication "no numbered reports"). */
+	if (data[0] == 0x0) {
+		bytes_returned++;
+	}
+
 	return bytes_returned;
-#endif
 }
 
+int HID_API_EXPORT HID_API_CALL hid_get_feature_report(hid_device *dev, unsigned char *data, size_t length)
+{
+	/* We could use HidD_GetFeature() instead, but it doesn't give us an actual length, unfortunately */
+	return hid_get_report(dev, IOCTL_HID_GET_FEATURE, data, length);
+}
 
 int HID_API_EXPORT HID_API_CALL hid_get_input_report(hid_device *dev, unsigned char *data, size_t length)
 {
-	BOOL res;
-#if 0
-	res = HidD_GetInputReport(dev->device_handle, data, length);
-	if (!res) {
-		register_error(dev, "HidD_GetInputReport");
-		return -1;
-	}
-	return length;
-#else
-	DWORD bytes_returned;
-
-	OVERLAPPED ol;
-	memset(&ol, 0, sizeof(ol));
-
-	res = DeviceIoControl(dev->device_handle,
-		IOCTL_HID_GET_INPUT_REPORT,
-		data, (DWORD) length,
-		data, (DWORD) length,
-		&bytes_returned, &ol);
-
-	if (!res) {
-		if (GetLastError() != ERROR_IO_PENDING) {
-			/* DeviceIoControl() failed. Return error. */
-			register_error(dev, "Send Input Report DeviceIoControl");
-			return -1;
-		}
-	}
-
-	/* Wait here until the write is done. This makes
-	   hid_get_feature_report() synchronous. */
-	res = GetOverlappedResult(dev->device_handle, &ol, &bytes_returned, TRUE/*wait*/);
-	if (!res) {
-		/* The operation failed. */
-		register_error(dev, "Send Input Report GetOverLappedResult");
-		return -1;
-	}
-
-	return bytes_returned;
-#endif
+	/* We could use HidD_GetInputReport() instead, but it doesn't give us an actual length, unfortunately */
+	return hid_get_report(dev, IOCTL_HID_GET_INPUT_REPORT, data, length);
 }
 
 void HID_API_EXPORT HID_API_CALL hid_close(hid_device *dev)