Word-based pointer APIs

[oscbyspro]

The following APIs circumnavigate uninitialized NBKDoubleWidth pointee access (#67).

New UnsafePointer APIs

public func load <H>(_ word: UInt.Type, at index: Int) -> UInt where Pointee == NBKDoubleWidth<H>

New UnsafeMutablePointer APIs

public func store<H>(_ word: UInt,      at index: Int)         where Pointee == NBKDoubleWidth<H>
public func load <H>(_ type: UInt.Type, at index: Int) -> UInt where Pointee == NBKDoubleWidth<H>

[oscbyspro]

Hm. I do wonder, however, if the following is allowed. In that case, the above is not required.

let value = Int256.uninitialized { pointer in
    for index in  Int256.indices {
        pointer.pointee[index] = UInt.zero // subscript calls UnsafeMutableRawPointer/storeBytes(of:toByteOffset:as:)
    }
}

Edit: I suppose the subscript access needs to be set rather than _modify, if it is allowed.

[oscbyspro]

Hm. I suppose the following might count as a pointee read:

// pointer.pointee[index] = UInt.zero

set {
    let byteOffset = BitPattern.endiannessSensitiveByteOffset(unchecked: index)
    Swift.withUnsafeMutablePointer(to: &self) { pointer in // ⚠️ inout pointee
        UnsafeMutableRawPointer(pointer).storeBytes(of: newValue, toByteOffset: byteOffset, as: T.self)
    }
}

[oscbyspro]

I just want an initialized junk allocation 😣

[oscbyspro]

These APIs are (or would be) made obsolete by (#71).