md5.h

/* Copyright 2016 Google Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#ifndef GOOGLE_SERVICE_CONTROL_CLIENT_UTILS_MD5_H_
#define GOOGLE_SERVICE_CONTROL_CLIENT_UTILS_MD5_H_

#include <string>
#include <string.h>
#include "openssl/md5.h"

namespace google {
namespace service_control_client {

// Define a MD5 Digest by calling OpenSSL
class MD5 {
 public:
  MD5();

  // Updates the context with data.
  MD5& Update(const void* data, size_t size);

  // A helper function for const char*
  MD5& Update(const char* str) {
    return Update(str, strlen(str));
  }

  // A helper function for const string
  MD5& Update(const std::string& str) {
    return Update(str.data(), str.size());
  }

  // A helper function for int
  MD5& Update(int d) {
    return Update(&d, sizeof(d));
  }

  // The MD5 digest is always 128 bits = 16 bytes
  static const int kDigestLength = 16;

  // Returns the digest as string.
  std::string Digest();

  // A short form of generating MD5 for a string
  std::string operator()(const void* data, size_t size);

  // Converts a binary digest string to a printable string.
  // It is for debugging and unit-test only.
  static std::string DebugString(const std::string& digest);

 private:
  // MD5 context.
  MD5_CTX ctx_;
  // The final MD5 digest.
  unsigned char digest_[kDigestLength];
  // A flag to indicate if MD5_final is called or not.
  bool finalized_;
};

}  // namespace service_control_client
}  // namespace google

#endif  // GOOGLE_SERVICE_CONTROL_CLIENT_UTILS_MD5_H_