blob_encoding.h (2252B)
1 /* 2 * Copyright (c) 2018 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef LOGGING_RTC_EVENT_LOG_ENCODER_BLOB_ENCODING_H_ 12 #define LOGGING_RTC_EVENT_LOG_ENCODER_BLOB_ENCODING_H_ 13 14 #include <stddef.h> 15 16 #include <string> 17 #include <vector> 18 19 #include "absl/strings/string_view.h" 20 21 namespace webrtc { 22 23 // Encode/decode a sequence of strings, whose length is not known to be 24 // discernable from the blob itself (i.e. without being transmitted OOB), 25 // in a way that would allow us to separate them again on the decoding side. 26 // The number of blobs is assumed to be transmitted OOB. For example, if 27 // multiple sequences of different blobs are sent, but all sequences contain 28 // the same number of blobs, it is beneficial to not encode the number of blobs. 29 // 30 // EncodeBlobs() must be given a non-empty vector. The blobs themselves may 31 // be equal to "", though. 32 // EncodeBlobs() may not fail. 33 // EncodeBlobs() never returns the empty string. 34 // 35 // Calling DecodeBlobs() on an empty string, or with `num_of_blobs` set to 0, 36 // is an error. 37 // DecodeBlobs() returns an empty vector if it fails, e.g. due to a mismatch 38 // between `num_of_blobs` and `encoded_blobs`, which can happen if 39 // `encoded_blobs` is corrupted. 40 // When successful, DecodeBlobs() returns a vector of string_view objects, 41 // which refer to the original input (`encoded_blobs`), and therefore may 42 // not outlive it. 43 // 44 // Note that the returned std::string might have been reserved for significantly 45 // more memory than it ends up using. If the caller to EncodeBlobs() intends 46 // to store the result long-term, they should consider shrink_to_fit()-ing it. 47 std::string EncodeBlobs(const std::vector<std::string>& blobs); 48 std::vector<absl::string_view> DecodeBlobs(absl::string_view encoded_blobs, 49 size_t num_of_blobs); 50 51 } // namespace webrtc 52 53 #endif // LOGGING_RTC_EVENT_LOG_ENCODER_BLOB_ENCODING_H_