text: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef CRYPTO_SECURE_HASH_H_
  #define CRYPTO_SECURE_HASH_H_
  #pragma once
  
  #include "base/basictypes.h"
  
  namespace crypto {
  
  // A wrapper to calculate secure hashes incrementally, allowing to
  // be used when the full input is not known in advance.
  class SecureHash {
   public:
    enum Algorithm {
      SHA256,
    };
    virtual ~SecureHash() {}
  
    static SecureHash* Create(Algorithm type);
  
    virtual void Update(const void* input, size_t len) = 0;
    virtual void Finish(void* output, size_t len) = 0;
  
   protected:
    SecureHash() {}
  
   private:
    DISALLOW_COPY_AND_ASSIGN(SecureHash);
  };
  
  }  // namespace crypto
  
  #endif  // CRYPTO_SECURE_HASH_H_
  