判断图片格式

根据图片编码判断图片是jpeg, 还是png

 func loadImage()  {
        let url = URL(fileURLWithPath: "/Users/CC/Desktop/Project/FindLoveiOS/FindLove/Profile/111")
        do{
            let data = try Data(contentsOf: url)
            contentTypeForImageData(data: data)
        } catch{
            print(error)
        }
    }

   func contentTypeForImageData(data: Data) {
        var c : uint_fast8_t = 0
        data.copyBytes(to: &c, count: 1)
        switch c {
            case 0xFF:
                print("jpeg")
            case 0x89:
                print("png")
            case 0x47:
                print("gif")
            case 0x49:
                print("tiff")
        default:
            print("其他格式")
        }
    }