Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/openssldigest.h

@@ -0,0 +1,50 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_OPENSSLDIGEST_H_
+#define WEBRTC_BASE_OPENSSLDIGEST_H_
+
+#include <openssl/evp.h>
+
+#include "webrtc/base/messagedigest.h"
+
+namespace rtc {
+
+// An implementation of the digest class that uses OpenSSL.
+class OpenSSLDigest : public MessageDigest {
+ public:
+  // Creates an OpenSSLDigest with |algorithm| as the hash algorithm.
+  explicit OpenSSLDigest(const std::string& algorithm);
+  ~OpenSSLDigest();
+  // Returns the digest output size (e.g. 16 bytes for MD5).
+  virtual size_t Size() const;
+  // Updates the digest with |len| bytes from |buf|.
+  virtual void Update(const void* buf, size_t len);
+  // Outputs the digest value to |buf| with length |len|.
+  virtual size_t Finish(void* buf, size_t len);
+
+  // Helper function to look up a digest's EVP by name.
+  static bool GetDigestEVP(const std::string &algorithm,
+                           const EVP_MD** md);
+  // Helper function to look up a digest's name by EVP.
+  static bool GetDigestName(const EVP_MD* md,
+                            std::string* algorithm);
+  // Helper function to get the length of a digest.
+  static bool GetDigestSize(const std::string &algorithm,
+                            size_t* len);
+
+ private:
+  EVP_MD_CTX ctx_;
+  const EVP_MD* md_;
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_OPENSSLDIGEST_H_