e6b3f48a06
This is a reland of commit fa962ffc698bda5bc7306ac5c3fd626eef737775 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}
64 lines
1.6 KiB
C++
64 lines
1.6 KiB
C++
/*
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* Copyright (c) 2023 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/rtp_rtcp/source/leb128.h"
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#include <cstdint>
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namespace webrtc {
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int Leb128Size(uint64_t value) {
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int size = 0;
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while (value >= 0x80) {
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++size;
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value >>= 7;
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}
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return size + 1;
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}
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uint64_t ReadLeb128(const uint8_t*& read_at, const uint8_t* end) {
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uint64_t value = 0;
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int fill_bits = 0;
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while (read_at != end && fill_bits < 64 - 7) {
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uint8_t leb128_byte = *read_at;
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value |= uint64_t{leb128_byte & 0x7Fu} << fill_bits;
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++read_at;
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fill_bits += 7;
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if ((leb128_byte & 0x80) == 0) {
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return value;
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}
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}
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// Read 9 bytes and didn't find the terminator byte. Check if 10th byte
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// is that terminator, however to fit result into uint64_t it may carry only
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// single bit.
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if (read_at != end && *read_at <= 1) {
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value |= uint64_t{*read_at} << fill_bits;
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++read_at;
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return value;
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}
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// Failed to find terminator leb128 byte.
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read_at = nullptr;
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return 0;
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}
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int WriteLeb128(uint64_t value, uint8_t* buffer) {
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int size = 0;
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while (value >= 0x80) {
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buffer[size] = 0x80 | (value & 0x7F);
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++size;
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value >>= 7;
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}
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buffer[size] = value;
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++size;
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return size;
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}
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} // namespace webrtc
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