chromium/media/formats/webm/webm_crypto_helpers.cc

// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/formats/webm/webm_crypto_helpers.h"

#include <array>
#include <memory>

#include "base/containers/span.h"
#include "base/containers/span_reader.h"
#include "base/logging.h"
#include "base/numerics/byte_conversions.h"
#include "base/numerics/safe_conversions.h"
#include "media/base/decrypt_config.h"
#include "media/formats/webm/webm_constants.h"

namespace media {
namespace {

// Generates a 16 byte CTR counter block. The CTR counter block format is a
// CTR IV appended with a CTR block counter. |iv| is an 8 byte CTR IV.
// |iv_size| is the size of |iv| in bytes. Returns a string of
// kDecryptionKeySize bytes.
std::string GenerateWebMCounterBlock(base::span<const uint8_t> iv) { … }

bool ExtractSubsamples(base::span<const uint8_t> buf,
                       size_t frame_data_size,
                       size_t num_partitions,
                       std::vector<SubsampleEntry>* subsample_entries) { … }

}  // namespace anonymous

bool WebMCreateDecryptConfig(const uint8_t* data_ptr,
                             int data_size,
                             const uint8_t* key_id_ptr,
                             int key_id_size,
                             std::unique_ptr<DecryptConfig>* decrypt_config,
                             int* data_offset) { … }

}  // namespace media