Hi,
On Aug 29, 2016, at 6:03 AM, David Lawrie david.dljunk@gmail.com wrote:
+static void char_device_name_length(IOHIDDeviceRef device, char *name, int max_length) +{
- CFStringRef str = copy_device_name(device);
- CFIndex len = CFStringGetLength(str);
- if (name)
name[0] = 0;- if (max_length >= len)
- {
CFStringGetCString(str,name,max_length,kCFStringEncodingASCII);CFRelease(str);- }
- else
- {
CFStringRef substr = CFStringCreateWithSubstring(kCFAllocatorDefault, str, CFRangeMake(0, max_length));CFRelease(str);CFStringGetCString(substr,name,max_length,kCFStringEncodingASCII);CFRelease(substr);- }
+}
I realize you based this function on code from DInput. Unfortunately, that code is pretty badly broken. CFStringGetLength() returns the length of the string in UTF-16 code units, which is basically the same as WCHARs. It's not meaningful to compare that to a buffer size that's in ASCII chars.
Using ASCII is wrong, too. If the name has any non-ASCII characters in it, the conversion will just fail. Second, it's potentially unnecessarily restrictive. Your device_disabled_registry() function, by virtue of using the "A" variant RegQueryValueEx(), uses the ANSI code page, not ASCII. The ANSI code page could maybe handle more names than ASCII would.
You could get a wide string and then use WideCharToMultiByte() to convert it to CP_ACP, but since you control all of the relevant code, it's just better to work with wide strings throughout. Change your device_disabled_registry() and get_config_key() functions to accept a wide string. Then, you can safely use CFStringGetLength() and CFStringGetCharacters() to acquire the WCHAR-based wide string from the CFString. You can just cast a WCHAR* to a UniChar*.
-Ken