从原始表中提取值

Question

I get a table lensDistortionLookupTable which is a NSData of floats of from AVCalibrationData and want to cast it into an array. What's the right way to do it with Swift?

Answer 1

1. get the bytes from the Data with withUnsafeBytes
2. use it to create a UnsafeBufferPointer of Float32 (according to the doc)

3. cast it to a regular Array

    let float32size = MemoryLayout<Float32>.stride // should be 4, but do not hardcode let elementCount = data.count / float32Size let table: [Float32] = depthData.cameraCalibrationData!.lensDistortionLookupTable.withUnsafeBytes { return Array(UnsafeBufferPointer<Float32>(start: $0, count: elementCount)) }