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// Copyright 2018 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/base/subsample_entry.h"
#include "base/check.h"
#include "base/logging.h"
#include "base/numerics/safe_math.h"
#include "media/base/ranges.h"
namespace media {
bool VerifySubsamplesMatchSize(const std::vector<SubsampleEntry>& subsamples,
size_t input_size) {
base::CheckedNumeric<size_t> total_size = 0;
for (const auto& subsample : subsamples) {
// Add each entry separately to avoid the compiler doing the wrong thing.
total_size += subsample.clear_bytes;
total_size += subsample.cypher_bytes;
}
if (!total_size.IsValid() || total_size.ValueOrDie() != input_size) {
DVLOG(1) << "Subsample sizes do not equal input size";
return false;
}
return true;
}
std::vector<SubsampleEntry> EncryptedRangesToSubsampleEntry(
const uint8_t* start,
const uint8_t* end,
const Ranges<const uint8_t*>& encrypted_ranges) {
std::vector<SubsampleEntry> subsamples(encrypted_ranges.size());
const uint8_t* cur = start;
for (size_t i = 0; i < encrypted_ranges.size(); ++i) {
const uint8_t* encrypted_start = encrypted_ranges.start(i);
DCHECK_GE(encrypted_start, cur)
<< "Encrypted range started before the current buffer pointer.";
subsamples[i].clear_bytes = encrypted_start - cur;
const uint8_t* encrypted_end = encrypted_ranges.end(i);
subsamples[i].cypher_bytes = encrypted_end - encrypted_start;
cur = encrypted_end;
DCHECK_LE(cur, end) << "Encrypted range is outside the buffer range.";
}
// If there is more data in the buffer but not covered by encrypted_ranges,
// then it must be in the clear.
if (cur < end) {
subsamples.emplace_back(end - cur, 0);
}
return subsamples;
}
} // namespace media
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