text: 
  /*
  * hmac-sha512.h: accord to rfc 2104, rfc 4231 implements hmac-sha512
  *
  * Authors:
  * mardyu<michealyxd@hotmail.com>
  *
  * Copyright 2016 mardyu<michealyxd@hotmail.com>
  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  */
  
  #ifndef _HMAC_SHA512_H_
  #define _HMAC_SHA512_H_
  
  #include <stdint.h>
  #include <stdio.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  	int hmac_sha512(const char *k, size_t klen, const char *text, size_t textlen, char *out, size_t outlen);
  
  #ifdef __cplusplus
  }
  #endif // __cplusplus
  
  #endif // _HMAC_SHA512_H_
  