/// <summary>
/// Check a function is available for this version.
/// </summary>
/// <param name="functionInfo"></param>
/// <returns></returns>
public bool IsFunctionAvailable(LibVlcFunctionAttribute functionInfo)
{
var result = true;
if (functionInfo.MinVersion != null)
{
result = functionInfo.MinVersion < Version;
}
if (functionInfo.MaxVersion != null)
{
result = result && Version < functionInfo.MaxVersion;
}
if (functionInfo.Dev != null)
{
result = result && DevString == functionInfo.Dev;
}
return(result);
}
/// <summary>
/// 使用提供的指定版本的 LibVlc 库句柄初始化一个 LibVlcFunction
/// </summary>
/// <param name="libHandle">提供的 LibVlc 库句柄</param>
/// <param name="libVersion">库版本</param>
public LibVlcFunction(IntPtr libHandle, Version libVersion, String Dev)
{
IsEnable = false;
object[] attrs = typeof(T).GetCustomAttributes(typeof(LibVlcFunctionAttribute), false);
LibVlcFunctionAttribute functionInfo = null;
foreach (var item in attrs)
{
if (item is LibVlcFunctionAttribute)
{
functionInfo = item as LibVlcFunctionAttribute;
break;
}
}
if (functionInfo == null)
{
throw new Exception("对于 LibVlcFunction,需要添加 LibVlcFunctionAttribute 才能正常读取函数");
}
FunctionName = functionInfo.FunctionName;
if ((libVersion == null || ((functionInfo.MinVersion == null || functionInfo.MinVersion <= libVersion) && (functionInfo.MaxVersion == null || functionInfo.MaxVersion >= libVersion))) && (functionInfo.Dev == null || functionInfo.Dev == Dev))
{
IsEnable = true;
IntPtr procAddress;
try
{
procAddress = Win32API.GetProcAddress(libHandle, FunctionName);
}
catch (Win32Exception e)
{
throw new Exception(String.Format("在提供的 LibVlc 中找不到函数 {0}", FunctionName), e);
}
var del = Marshal.GetDelegateForFunctionPointer(procAddress, typeof(T));
functionDelegate = (T)Convert.ChangeType(del, typeof(T));
}
}
