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/*
* Copyright (c) 2018 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.
*/
#include "logging/rtc_event_log/encoder/blob_encoding.h"
#include <cstddef>
#include <cstdint>
#include <string>
#include <tuple>
#include <vector>
#include "absl/strings/string_view.h"
#include "logging/rtc_event_log/encoder/var_int.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
namespace webrtc {
std::string EncodeBlobs(const std::vector<std::string>& blobs) {
RTC_DCHECK(!blobs.empty());
size_t result_length_bound = kMaxVarIntLengthBytes * blobs.size();
for (const auto& blob : blobs) {
// Providing an input so long that it would cause a wrap-around is an error.
RTC_DCHECK_GE(result_length_bound + blob.length(), result_length_bound);
result_length_bound += blob.length();
}
std::string result;
result.reserve(result_length_bound);
// First, encode all of the lengths.
for (absl::string_view blob : blobs) {
result += EncodeVarInt(blob.length());
}
// Second, encode the actual blobs.
for (absl::string_view blob : blobs) {
result.append(blob.data(), blob.length());
}
RTC_DCHECK_LE(result.size(), result_length_bound);
return result;
}
std::vector<absl::string_view> DecodeBlobs(absl::string_view encoded_blobs,
size_t num_of_blobs) {
if (encoded_blobs.empty()) {
RTC_LOG(LS_WARNING) << "Corrupt input; empty input.";
return std::vector<absl::string_view>();
}
if (num_of_blobs == 0u) {
RTC_LOG(LS_WARNING)
<< "Corrupt input; number of blobs must be greater than 0.";
return std::vector<absl::string_view>();
}
// Read the lengths of all blobs.
std::vector<uint64_t> lengths(num_of_blobs);
for (size_t i = 0; i < num_of_blobs; ++i) {
bool success = false;
std::tie(success, encoded_blobs) = DecodeVarInt(encoded_blobs, &lengths[i]);
if (!success) {
RTC_LOG(LS_WARNING) << "Corrupt input; varint decoding failed.";
return std::vector<absl::string_view>();
}
}
// Read the blobs themselves.
std::vector<absl::string_view> blobs(num_of_blobs);
for (size_t i = 0; i < num_of_blobs; ++i) {
if (lengths[i] > encoded_blobs.length()) {
RTC_LOG(LS_WARNING) << "Corrupt input; blob sizes exceed input size.";
return std::vector<absl::string_view>();
}
blobs[i] = encoded_blobs.substr(0, lengths[i]);
encoded_blobs = encoded_blobs.substr(lengths[i]);
}
if (!encoded_blobs.empty()) {
RTC_LOG(LS_WARNING) << "Corrupt input; unrecognized trailer.";
return std::vector<absl::string_view>();
}
return blobs;
}
} // namespace webrtc
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