swift MD5加密源码的实例详解

#ifndef bridge_h  #define bridge_h    #import <CommonCrypto/CommonDigest.h>    #endif /* bridge_h */  

import Foundation    extension String {    var md5 : String{      let str = self.cString(using: String.Encoding.utf8)      let strLen = CC_LONG(self.lengthOfBytes(using: String.Encoding.utf8))      let digestLen = Int(CC_MD5_DIGEST_LENGTH)      let result = UnsafeMutablePointer<CUnsignedChar>.allocate(capacity: digestLen)            CC_MD5(str!, strLen, result)            let hash = NSMutableString()      for i in 0 ..< digestLen {        hash.appendFormat("%02x", result[i])      }      result.deinitialize()            return String(format: hash as String)    }  }