mirror of
https://github.com/mollyim/webrtc.git
synced 2025-05-13 13:50:40 +01:00
e6b3f48a06
This is a reland of commit fa962ffc69
Original change's description:
> Move leb128 helper functions into own build target
>
> to remove duplicated implementation of these functions between av1 packetizer, av1 depacketizer and video allocation rtp header extension
>
> Bug: None
> Change-Id: I30049f31c289bdb9e0aad6520f5145d1f999e635
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/290731
> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
> Reviewed-by: Philip Eliasson <philipel@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#39069}
Bug: None
Change-Id: I091276868599a6716407db2972457507ddd46a8c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/290961
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39135}
63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
/*
|
|
* Copyright (c) 2023 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 "modules/rtp_rtcp/source/leb128.h"
|
|
|
|
#include <cstdint>
|
|
|
|
namespace webrtc {
|
|
|
|
int Leb128Size(uint64_t value) {
|
|
int size = 0;
|
|
while (value >= 0x80) {
|
|
++size;
|
|
value >>= 7;
|
|
}
|
|
return size + 1;
|
|
}
|
|
|
|
uint64_t ReadLeb128(const uint8_t*& read_at, const uint8_t* end) {
|
|
uint64_t value = 0;
|
|
int fill_bits = 0;
|
|
while (read_at != end && fill_bits < 64 - 7) {
|
|
uint8_t leb128_byte = *read_at;
|
|
value |= uint64_t{leb128_byte & 0x7Fu} << fill_bits;
|
|
++read_at;
|
|
fill_bits += 7;
|
|
if ((leb128_byte & 0x80) == 0) {
|
|
return value;
|
|
}
|
|
}
|
|
// Read 9 bytes and didn't find the terminator byte. Check if 10th byte
|
|
// is that terminator, however to fit result into uint64_t it may carry only
|
|
// single bit.
|
|
if (read_at != end && *read_at <= 1) {
|
|
value |= uint64_t{*read_at} << fill_bits;
|
|
++read_at;
|
|
return value;
|
|
}
|
|
// Failed to find terminator leb128 byte.
|
|
read_at = nullptr;
|
|
return 0;
|
|
}
|
|
|
|
int WriteLeb128(uint64_t value, uint8_t* buffer) {
|
|
int size = 0;
|
|
while (value >= 0x80) {
|
|
buffer[size] = 0x80 | (value & 0x7F);
|
|
++size;
|
|
value >>= 7;
|
|
}
|
|
buffer[size] = value;
|
|
++size;
|
|
return size;
|
|
}
|
|
|
|
} // namespace webrtc
|