Swift 3：如何将字节数组转换为Data？

Question

I know how to convert int value into data

let value: NSInteger = 1
let valueData:Data = Data(buffer: UnsafeBufferPointer(start: &intVal, count: 1))

Now I want to do the same with RGB color denoted in the following way 0xRRGGBB

How can I achieve it? Should I write it as String, eq "543621", then convert it into byte array then convert it to Data?

Answer 1

It seems it would be appropriate to store the color as an UInt32 instance, in which case you've already posted a method for initializing a Data instance from it

var pink: UInt32 = 0xCC6699

let pinkData = Data(buffer: UnsafeBufferPointer(start: &pink, count: 1))
print(pinkData.map {$0}) // [153, 102, 204, 0]

print(0x99, 0x66, 0xCC) // 153 102 204

As MartinR points out in a comment below, to ensure the hex number representation 0xCC6699 is stored in its little endian representation (even for systems which employ big endian host byte order), the pink variable should be initialized as:

var pink = UInt32(0xCC6699).littleEndian

// or ...
var pink = UInt32(littleEndian: 0xCC6699)