The review of std.hash package

[Christophe Travert]

I'm not familiar with hash functions in general.

I think the core of std.hash is the digest function:

digestType!Hash digest(Hash)(scope const(void[])[] data...) 
if(isDigest!Hash)
{
    Hash hash;
    hash.start();
    foreach(datum; data)
        hash.put(cast(const(ubyte[]))datum);
    return hash.finish();
}

That seems to be too restrictive: you can only provide a void[][] or one 
or several void[], but you should be able to give it any range of 
void[] or of ubyte[] like:

auto dig = file.byChunk.digest!MD5;

That's the point of the range interface.

this can be done by templatizing the function, something like 
(untested):

template digest(Hash) if(isDigest!Hash)
{
  auto digest(R)(R data)
    if (isInputRange!R &&  is(ElementType!R : void[])
  {
    Hash hash;
    hash.start();
    data.copy(hash);
    return hash.finish();
  }
}

An interesting overload for range of single ubyte could be provided. 
This overload would fill a buffer of with data from this range,  
feed the hash, and start again.