Load misaligned data from a blob of bytes. I don't know if this is correct.

load-misaligned.swift

import Foundation

let data = Data([0, 0, 0, 0, 0, 0x11, 0x22, 0x33, 0x44, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
data.count

extension UnsafeRawBufferPointer {
    func loadUnaligned<T>(fromByteOffset offset: Int, as: T.Type) -> T {
        // Allocate correctly aligned memory and copy bytes there
        let alignedPointer = UnsafeMutableRawPointer.allocate(byteCount: MemoryLayout<T>.stride, alignment: MemoryLayout<T>.alignment)
        defer {
            alignedPointer.deallocate()
        }
        alignedPointer.copyMemory(from: baseAddress!.advanced(by: offset), byteCount: MemoryLayout<T>.size)
        return alignedPointer.load(as: T.self)
    }
}

// Load unaligned big-endian UInt32
let uint32 = data.withUnsafeBytes { bytes in
    bytes.loadUnaligned(fromByteOffset: 5, as: UInt32.self).bigEndian
}
print(uint32) // → 287454020
print(String(uint32, radix: 16)) // → "11223344"