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      1 /*
      2  * libjingle
      3  * Copyright 2004--2012, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #ifndef TALK_BASE_OPENSSLDIGEST_H_
     29 #define TALK_BASE_OPENSSLDIGEST_H_
     30 
     31 #include <openssl/evp.h>
     32 
     33 #include "talk/base/messagedigest.h"
     34 
     35 namespace talk_base {
     36 
     37 // An implementation of the digest class that uses OpenSSL.
     38 class OpenSSLDigest : public MessageDigest {
     39  public:
     40   // Creates an OpenSSLDigest with |algorithm| as the hash algorithm.
     41   explicit OpenSSLDigest(const std::string& algorithm);
     42   ~OpenSSLDigest();
     43   // Returns the digest output size (e.g. 16 bytes for MD5).
     44   virtual size_t Size() const;
     45   // Updates the digest with |len| bytes from |buf|.
     46   virtual void Update(const void* buf, size_t len);
     47   // Outputs the digest value to |buf| with length |len|.
     48   virtual size_t Finish(void* buf, size_t len);
     49 
     50   // Helper function to look up a digest's EVP by name.
     51   static bool GetDigestEVP(const std::string &algorithm,
     52                            const EVP_MD** md);
     53   // Helper function to look up a digest's name by EVP.
     54   static bool GetDigestName(const EVP_MD* md,
     55                             std::string* algorithm);
     56   // Helper function to get the length of a digest.
     57   static bool GetDigestSize(const std::string &algorithm,
     58                             size_t* len);
     59 
     60  private:
     61   EVP_MD_CTX ctx_;
     62   const EVP_MD* md_;
     63 };
     64 
     65 }  // namespace talk_base
     66 
     67 #endif  // TALK_BASE_OPENSSLDIGEST_H_
     68