比较iPhone上的UIImage和服务器上的文件的MD5哈希值

import hashlib

def calculate_md5(file_path):
    m = hashlib.md5()
    with open(file_path, "rb") as f:
        for chunk in iter(lambda: f.read(4096), b""):
            m.update(chunk)
    return m.hexdigest()

import CoreGraphics

func calculateImageHash(image: UIImage) -> String {
    let context = CGContext(data: nil, width: image.size.width, height: image.size.height, bitsPerComponent: 8, bytesPerRow: 0, space: CGColorSpaceCreateWithName(CGColorSpace.displayP3), bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.noneSkipLast.rawValue))
    context?.draw(image.cgImage!, in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))

    let data = context!.data
    let hash = CFDataGetBytePtr(data)
    let hashValue = CFDataGetLength(data)

    let md5 = CFDataCreateMutable(nil, hashValue)
    let messageDigest = CFDataCreateMutable(nil, hashValue)
    let result = CFDataGetMutableBytePtr(md5)
    let status = CFDataGetMutableBytePtr(messageDigest)

    for var index = 0; index < hashValue; index++ {
        result[index] = hash[index]
    }

    status[0] = 0x80
    status[6] = 0x00
    status[7] = 0x00

    CFDataReplaceMutableByteOrder(md5, 0)
    CFDataReplaceMutableByteOrder(messageDigest, 0)

    let algorithm = CFDataCreateAlgorithm(kCFDataGetBytesPerElement, md5)
    let messageDigestFinal = CFDataCreateAlgorithm(kCFDataGetBytesPerElement, messageDigest)

    let hashValuePtr = CFDataGetBytePtr(md5)
    let hashValue = CFDataGetLength(md5)

    let resultPtr = CFDataGetMutableBytePtr(result)
    let result = CFDataGetLength(result)

    for var index = 0; index < hashValue; index++ {
        resultPtr[index] = hashValuePtr[index]
    }

    CFDataWriteToURL(messageDigestFinal, nil, nil)
    let messageDigestFinalData = CFDataGetURL(messageDigestFinal)
    let messageDigestFinal = CFDataCreate(nil, messageDigestFinalData)
    let resultFinal = CFDataCreate(nil, result)

    let messageDigest = CFDataCreateMutable(nil, hashValue)
    let result = CFDataCreateMutable(nil, hashValue)

    for var index = 0; index < hashValue; index++ {
        messageDigest[index] = resultFinal[index]
    }

    for var index = 0; index < hashValue; index++ {
        result[index] = messageDigest[index]
    }

    return result as String
}