Add SubsampleEntry constructor.

media/base/decrypt_config.h

 // Copyright (c) 2012 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 MEDIA_BASE_DECRYPT_CONFIG_H_
 #define MEDIA_BASE_DECRYPT_CONFIG_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // The Common Encryption spec provides for subsample encryption, where portions
 // of a sample are set in cleartext. A SubsampleEntry specifies the number of
 // clear and encrypted bytes in each subsample. For decryption, all of the
 // encrypted bytes in a sample should be considered a single logical stream,
 // regardless of how they are divided into subsamples, and the clear bytes
 // should not be considered as part of decryption. This is logically equivalent
 // to concatenating all 'cypher_bytes' portions of subsamples, decrypting that
 // result, and then copying each byte from the decrypted block over the
 // position of the corresponding encrypted byte.
 struct SubsampleEntry {
+  SubsampleEntry() : clear_bytes(0), cypher_bytes(0) {}

[ddorwin, 2014/11/25 20:47:48]

Do we need this? It seems like something that should never be used.

[xhwang, 2014/11/25 22:13:44]

This is needed as the default ctor because we need to  put SubsampleEntry in a
std::vector.

+  SubsampleEntry(uint32 clear_bytes, uint32 cypher_bytes)
+      : clear_bytes(clear_bytes), cypher_bytes(cypher_bytes) {}
   uint32 clear_bytes;
   uint32 cypher_bytes;
 };
 
 // Contains all information that a decryptor needs to decrypt a media sample.
 class MEDIA_EXPORT DecryptConfig {
  public:
   // Keys are always 128 bits.
   static const int kDecryptionKeySize = 16;
 
   // |key_id| is the ID that references the decryption key for this sample.
   // |iv| is the initialization vector defined by the encrypted format.
   //   Currently |iv| must be 16 bytes as defined by WebM and ISO. Or must be
   //   empty which signals an unencrypted frame.
   // |subsamples| defines the clear and encrypted portions of the sample as
   //   described above. A decrypted buffer will be equal in size to the sum
   //   of the subsample sizes.
   DecryptConfig(const std::string& key_id,
                 const std::string& iv,
                 const std::vector<SubsampleEntry>& subsamples);
   ~DecryptConfig();
 
   const std::string& key_id() const { return key_id_; }
   const std::string& iv() const { return iv_; }
   const std::vector<SubsampleEntry>& subsamples() const { return subsamples_; }
 
+  // Returns true if all fields in |config| match this config.
+  bool Matches(const DecryptConfig& config) const;
+
  private:
   const std::string key_id_;
 
   // Initialization vector.
   const std::string iv_;
 
   // Subsample information. May be empty for some formats, meaning entire frame
   // (less data ignored by data_offset_) is encrypted.
   const std::vector<SubsampleEntry> subsamples_;
 
   DISALLOW_COPY_AND_ASSIGN(DecryptConfig);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_DECRYPT_CONFIG_H_