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Added default size getter and shortened version to CallMethodWithTypedBuf

pull/60/head
David Hall 2019-04-18 20:38:45 -06:00
parent 5f4f48e9a7
commit dbdcdd2107
1 changed files with 16 additions and 3 deletions
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19
PInvoke/Shared/FunctionHelper.cs
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@ -99,17 +99,30 @@ namespace Vanara.PInvoke
{
TSize sz = default;
result = default;
var err = getSize(ref sz);
var err = (getSize ?? GetSize)(ref sz);
if (err.Failed) return err;
var len = sz.ToInt32(null);
using (var buf = new SafeHGlobalHandle(len))
using (var buf = new SafeHGlobalHandle(sz.ToInt32(null)))
{
var ret = method(buf.DangerousGetHandle(), ref sz);
result = (outConverter ?? Conv)(buf.DangerousGetHandle(), sz);
return ret;
}
Win32Error GetSize(ref TSize sz1) { var serr = method(IntPtr.Zero, ref sz1); return serr == Win32Error.ERROR_INSUFFICIENT_BUFFER || serr == Win32Error.ERROR_MORE_DATA ? Win32Error.ERROR_SUCCESS : serr; }
TOut Conv(IntPtr p, TSize s) => p.ToStructure<TOut>();
}
/// <summary>Calls a method with buffer for a type and gets the result or error.</summary>
/// <typeparam name="TOut">The return type.</typeparam>
/// <typeparam name="TSize">The type of the size result. This is usually <see cref="int"/> or <see cref="uint"/>.</typeparam>
/// <param name="method">The lambda or method to call into.</param>
/// <param name="getSize">Method to get the size of the buffer.</param>
/// <param name="outConverter">An optional method to convert the pointer to the type specified by <typeparamref name="TOut"/>. By default, this will marshal the pointer to the structure.</param>
/// <returns>The resulting value of <typeparamref name="TOut"/>.</returns>
public static TOut CallMethodWithTypedBuf<TOut, TSize>(PtrFunc<TSize> method, SizeFunc<TSize> getSize = null, Func<IntPtr, TSize, TOut> outConverter = null) where TSize : struct, IConvertible
{
CallMethodWithTypedBuf(getSize, method, out var res, outConverter).ThrowIfFailed();
return res;
}
}
}