How exactly do I use this to calculate CRC value for a file?

[cryodream]

Hi,
Like the title says, how do I use this library to calculate hashes for files?

Thanks for any help.

[force-net]

Example code:

var crc = 0u;
using (var f = File.OpenRead("somefile"))
{
	var buffer = new byte[65536];
	while (true)
	{
		var count = f.Read(buffer, 0, buffer.Length);
		if (count == 0)
			break;
		crc = Crc32Algorithm.Append(crc, buffer, 0, count);
	}
}

Console.WriteLine(crc);

[kgamecarter]

using (var stream = new FileStream(path, FileMode.Open))
using (var crc = new Crc32Algorithm())
{
    var crc32bytes = crc.Compute(stream);
    var crc32 = BitConverter.ToUInt32(crc32bytes, 0);
}

[Agagamand]

This better:

private string GetCRC32C(string filename, IProgress<double> progress = null)
{
    uint hash = 0;
    byte[] buffer = new byte[1048576]; // 1MB buffer

    using (var entryStream = File.OpenRead(filename))
    {
        int currentBlockSize = 0;

        while ((currentBlockSize = entryStream.Read(buffer, 0, buffer.Length)) > 0)
        {
            hash = Crc32CAlgorithm.Append(hash, buffer, 0, currentBlockSize);
            progress?.Report((double)currentBlockSize / entryStream.Length * 100);
        }
    }
    return hash.ToString("X8");
}

Maybe you should add this example to the Wiki? https://github.com/force-net/Crc32.NET/wiki

[PeterCodar]

This better:

Could you please let us know why this [is] better?

[force-net]

@PeterCodar
I do not know...
Differences:

• Larger buffer
• Return value is string
• Support for IProgress interface. But with this interface - last progress does not notify,
  and length of file is calculated every time
  May be it uses larger buffer, so it can be faster someway. Also, code uses IProgress interface. It can be helpful? but usage of this interface is bad - no 100% progress and length of file is calculated every time (I do not know complexity of this operation). Also, progress is not cumulative, it sends the same value every time

[EnduringBeta]

Adding one or more working examples to the readme would dramatically improve a person's experience using the package if new to them, like me. Thanks to those who asked and answered this question over here.