zLib Compression

compression-example.swift

typealias Byte = UInt8

let size: Int = 100000

var simpleData = [Byte](repeating: 3, count: size)
var dataCompressed = [Byte](repeating: 6, count: size)

simpleData[3] = 2
simpleData[4] = 1

var sizeDataCompressed: uLongf = 0

let result = compress2( &dataCompressed, &sizeDataCompressed,
                        &simpleData, uLong(size), Z_BEST_SPEED )

switch result {
    case Z_OK:
        print("Everything's OK")
    case Z_BUF_ERROR:
        print("Buffer error")
    default:
        print("Some other error")
}

print("Size after compression is: \(sizeDataCompressed)")

It builds and runs, but result is always -5 which means the destination buffer is not large enough to store the result.