How to compute Hash (MD5 or SHA) of a large file with C# in Windows Store App

Question

PROBLEM:

"If you try to calculate md5 or sha in a Windows 8 Metro App using the metod HashData(IBuffer) with a buffer that contains a large file, you receive the OutOfMemoryException because the buffer is very big (contains a copy in byte of the original file)."

SOLUTION:

//NB: "file" is a "StorageFile" previously openedHashAlgorithmProvider md5 = Windows.Security.Cryptography.Core.HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Md5);
//in this example I use HashAlgorithmNames.Md5, you can replace it with HashAlgorithmName.Sha1, etc...

HashAlgorithmProvider alg = Windows.Security.Cryptography.Core.HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Md5);
var stream = await file.OpenStreamForReadAsync();
var inputStream = stream.AsInputStream();
uint capacity = 100000000;
Windows.Storage.Streams.Buffer buffer = new Windows.Storage.Streams.Buffer(capacity);
var hash = alg.CreateHash();

while (true)
{
    await inputStream.ReadAsync(buffer, capacity, InputStreamOptions.None);
    if (buffer.Length > 0)
        hash.Append(buffer);
    else
        break;
}

string hashText = CryptographicBuffer.EncodeToHexString(hash.GetValueAndReset()).ToUpper();

inputStream.Dispose();
stream.Dispose();

I hope that this is helpful :)