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_VAR_INT_H_ 12 #define LOGGING_RTC_EVENT_LOG_ENCODER_VAR_INT_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include <string> 18 19 #include "absl/strings/string_view.h" 20 #include "rtc_base/bit_buffer.h" 21 22 namespace webrtc { 23 24 extern const size_t kMaxVarIntLengthBytes; 25 26 // Encode a given uint64_t as a varint. From least to most significant, 27 // each batch of seven bits are put into the lower bits of a byte, and the last 28 // remaining bit in that byte (the highest one) marks whether additional bytes 29 // follow (which happens if and only if there are other bits in |input| which 30 // are non-zero). 31 // Notes: If input == 0, one byte is used. If input is uint64_t::max, exactly 32 // kMaxVarIntLengthBytes are used. 33 std::string EncodeVarInt(uint64_t input); 34 35 // Inverse of EncodeVarInt(). 36 // If decoding is successful, a non-zero number is returned, indicating the 37 // number of bytes read from |input|, and the decoded varint is written 38 // into |output|. 39 // If not successful, 0 is returned, and |output| is not modified. 40 size_t DecodeVarInt(absl::string_view input, uint64_t* output); 41 42 // Same as other version, but uses a rtc::BitBuffer for input. 43 // Some bits may be consumed even if a varint fails to be read. 44 size_t DecodeVarInt(rtc::BitBuffer* input, uint64_t* output); 45 46 } // namespace webrtc 47 48 #endif // LOGGING_RTC_EVENT_LOG_ENCODER_VAR_INT_H_ 49