Convert into generic function - swift

Question

I am writing an iOS app in Swift. My class has below functions for reading bytebuffer. Below all functions do same task but work on different number types. So, how to convert these functions into a single function using generics?
var array = [UInt8]()
private var currentIndex: Int = 0
private let hostEndianness: Endianness = OSHostByteOrder() == OSLittleEndian ? .little : .big
private var currentEndianness: Endianness = .big
public func getUInt16() -> UInt16 {
let check=(currentIndex + MemoryLayout<UInt16>.size) - 1
if array.indices.contains(check){
let result = from(Array(array[currentIndex..<currentIndex + MemoryLayout<UInt16>.size]), UInt16.self)
currentIndex += MemoryLayout<UInt16>.size
return result.littleEndian
}else{
return 0
}
}
public func getInt32() -> Int32 {
let check=(currentIndex + MemoryLayout<Int32>.size) - 1
if array.indices.contains(check){
let result = from(Array(array[currentIndex..<currentIndex + MemoryLayout<Int32>.size]), Int32.self)
currentIndex += MemoryLayout<Int32>.size
return result.littleEndian
}else{
return 0
}
}
public func getFloat() -> Float {
let check=(currentIndex + MemoryLayout<UInt32>.size) - 1
if array.indices.contains(check){
let result = from(Array(array[currentIndex..<currentIndex + MemoryLayout<UInt32>.size]), UInt32.self)
currentIndex += MemoryLayout<UInt32>.size
return Float(bitPattern: result.littleEndian)
}else{
return 0.0
}
}
public func getDouble() -> Double {
let check=(currentIndex + MemoryLayout<UInt64>.size) - 1
if array.indices.contains(check){
let result = from(Array(array[currentIndex..<currentIndex + MemoryLayout<UInt64>.size]), UInt64.self)
currentIndex += MemoryLayout<UInt64>.size
return Double(bitPattern: result.bigEndian)
}else{
return 0.0
}
}
The only difference in the above functions is types: Float, double, UInt16, Int32.
From Function:
private func from<T>(_ value: [UInt8], _: T.Type) -> T {
return value.withUnsafeBytes {
$0.load(fromByteOffset: 0, as: T.self)
}
}
My Solution:
public func getNumber<T:Numeric>() -> T {
let check=(currentIndex + MemoryLayout<T>.size) - 1
if array.indices.contains(check){
let result = from(Array(array[currentIndex..<currentIndex + MemoryLayout<T>.size]), T.self)
currentIndex += MemoryLayout<T>.size
return result.bigEndian
}else{
return 0
}
}
Error:
Value of type 'T' has no member 'bigEndian'