private void ReadProviderList()
{
var lpl = new LINEPROVIDERLIST();
int rc, neededSize = 1024;
do
{
lpl.dwTotalSize = neededSize;
IntPtr pLpl = Marshal.AllocHGlobal(neededSize);
Marshal.StructureToPtr(lpl, pLpl, true);
rc = NativeMethods.lineGetProviderList((int)TapiVersion.V21, pLpl);
Marshal.PtrToStructure(pLpl, lpl);
if (lpl.dwNeededSize > neededSize)
{
neededSize = lpl.dwNeededSize;
rc = NativeMethods.LINEERR_STRUCTURETOOSMALL;
}
else if (rc == NativeMethods.LINEERR_OK)
{
var rawBuffer = new byte[lpl.dwUsedSize];
Marshal.Copy(pLpl, rawBuffer, 0, lpl.dwUsedSize);
for (int i = 0; i < lpl.dwNumProviders; i++)
{
_providers.Add(ReadTapiProviderInfo(lpl, rawBuffer, i));
}
}
Marshal.FreeHGlobal(pLpl);
}while (rc == NativeMethods.LINEERR_STRUCTURETOOSMALL);
}
private static TapiProvider ReadTapiProviderInfo(LINEPROVIDERLIST lpl, byte[] rawBuffer, int pos)
{
var lpe = new LINEPROVIDERENTRY();
int size = Marshal.SizeOf(lpe);
pos = lpl.dwProviderListOffset + (pos * size);
IntPtr pLpe = Marshal.AllocHGlobal(size);
Marshal.Copy(rawBuffer, pos, pLpe, size);
Marshal.PtrToStructure(pLpe, lpe);
Marshal.FreeHGlobal(pLpe);
return(new TapiProvider(lpe.dwPermanentProviderID,
NativeMethods.GetString(rawBuffer,
lpe.dwProviderFilenameOffset, lpe.dwProviderFilenameSize,
NativeMethods.STRINGFORMAT_UNICODE)));
}
