Creates a deep copy of a CVPixelBuffer. Compatible with Swift 2.3.

CVPixelBufferDeepCopy.swift

extension CVPixelBuffer
{
    /// Deep copy a CVPixelBuffer:
    ///   http://stackoverflow.com/questions/38335365/pulling-data-from-a-cmsamplebuffer-in-order-to-create-a-deep-copy
    func copy() -> CVPixelBuffer
    {
        precondition(CFGetTypeID(self) == CVPixelBufferGetTypeID(), "copy() cannot be called on a non-CVPixelBuffer")

        var _copy: CVPixelBuffer?

        CVPixelBufferCreate(
            nil,
            CVPixelBufferGetWidth(self),
            CVPixelBufferGetHeight(self),
            CVPixelBufferGetPixelFormatType(self),
            CVBufferGetAttachments(self, .ShouldPropagate),
            &_copy)

        guard let copy = _copy else { fatalError() }

        CVPixelBufferLockBaseAddress(self, .ReadOnly)
        CVPixelBufferLockBaseAddress(copy, [])
        defer
        {
            CVPixelBufferUnlockBaseAddress(copy, [])
            CVPixelBufferUnlockBaseAddress(self, .ReadOnly)
        }

        for plane in 0 ..< CVPixelBufferGetPlaneCount(self)
        {
            let dest        = CVPixelBufferGetBaseAddressOfPlane(copy, plane)
            let source      = CVPixelBufferGetBaseAddressOfPlane(self, plane)
            let height      = CVPixelBufferGetHeightOfPlane(self, plane)
            let bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(self, plane)

            memcpy(dest, source, height * bytesPerRow)
        }

        return copy
    }
}