在Swift中将float转换为little endian

Question

I'm processing data from a socket and successfully converting the data to Int and Floats with:

let float = data.withUnsafeBytes { $0.pointee } as Float

Everything was working fine until one iPhone 6 Plus seemed to be using Big Endian for the data.

I was able to convert the Int without much effort with:

let uint32 = UInt32(littleEndian: data.withUnsafeBytes { $0.pointee })
let int = Int(uint32)

Unfortunately, I cannot seem to figure out how to convert the float data.

Answer 1

A possible solution is to read the data into a 32-bit integer first, convert the endianness, and finally create the floating point number with the same bit pattern:

let uint32 = UInt32(bigEndian: data.withUnsafeBytes { $0.pointee })
let float = Float(bitPattern: uint32)

Example:

// IEEE-754 big-endian representation of 1.5:
let data = Data(bytes: [0x3f, 0xc0, 0x00, 0x00])
print(data as NSData)

let uint32 = UInt32(bigEndian: data.withUnsafeBytes { $0.pointee })
let float = Float(bitPattern: uint32)

print(float) // 1.5