windows: Set maximum buffer for USB strings to 0xFFF wide characters

Limit the size of the buffer passed to hid_get_manufacturer_string(),
hid_get_product_string(), and hid_get_serial_number_string() because
calling the underlying win32 functions with larger buffers causes them
to fail.

Author: amullins83

windows/hid.c

@@ -36,6 +36,10 @@ typedef LONG NTSTATUS;
 #define _wcsdup wcsdup
 #endif
 
+/* The maximum number of characters that can be passed into the
+   HidD_Get*String() functions without it failing.*/
+#define MAX_STRING_WCHARS 0xFFF
+
 /*#define HIDAPI_USE_DDK*/
 
 #ifdef __cplusplus
@@ -62,6 +66,9 @@ extern "C" {
 
 #include "hidapi.h"
 
+#undef MIN
+#define MIN(x,y) ((x) < (y)? (x): (y))
+
 #ifdef _MSC_VER
 	/* Thanks Microsoft, but I know how to use strncpy(). */
 	#pragma warning(disable:4996)
@@ -811,7 +818,7 @@ int HID_API_EXPORT_CALL HID_API_CALL hid_get_manufacturer_string(hid_device *dev
 {
 	BOOL res;
 
-	res = HidD_GetManufacturerString(dev->device_handle, string, sizeof(wchar_t) * maxlen);
+	res = HidD_GetManufacturerString(dev->device_handle, string, sizeof(wchar_t) * MIN(maxlen, MAX_STRING_WCHARS));
 	if (!res) {
 		register_error(dev, "HidD_GetManufacturerString");
 		return -1;
@@ -824,7 +831,7 @@ int HID_API_EXPORT_CALL HID_API_CALL hid_get_product_string(hid_device *dev, wch
 {
 	BOOL res;
 
-	res = HidD_GetProductString(dev->device_handle, string, sizeof(wchar_t) * maxlen);
+	res = HidD_GetProductString(dev->device_handle, string, sizeof(wchar_t) * MIN(maxlen, MAX_STRING_WCHARS));
 	if (!res) {
 		register_error(dev, "HidD_GetProductString");
 		return -1;
@@ -837,7 +844,7 @@ int HID_API_EXPORT_CALL HID_API_CALL hid_get_serial_number_string(hid_device *de
 {
 	BOOL res;
 
-	res = HidD_GetSerialNumberString(dev->device_handle, string, sizeof(wchar_t) * maxlen);
+	res = HidD_GetSerialNumberString(dev->device_handle, string, sizeof(wchar_t) * MIN(maxlen, MAX_STRING_WCHARS));
 	if (!res) {
 		register_error(dev, "HidD_GetSerialNumberString");
 		return -1;
@@ -850,7 +857,7 @@ int HID_API_EXPORT_CALL HID_API_CALL hid_get_indexed_string(hid_device *dev, int
 {
 	BOOL res;
 
-	res = HidD_GetIndexedString(dev->device_handle, string_index, string, sizeof(wchar_t) * maxlen);
+	res = HidD_GetIndexedString(dev->device_handle, string_index, string, sizeof(wchar_t) * MIN(maxlen, MAX_STRING_WCHARS));
 	if (!res) {
 		register_error(dev, "HidD_GetIndexedString");
 		return -1;