android13/device/google/atv/audio_proxy/service/RingBufferUtil.cpp

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2.4 KiB
C++

// Copyright (C) 2021 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "RingBufferUtil.h"
#include <android-base/logging.h>
namespace audio_proxy::service {
namespace {
struct CopyDesc {
int8_t* dst = nullptr;
const int8_t* src = nullptr;
size_t len = 0;
};
} // namespace
void copyRingBuffer(int8_t* dstBuf1, size_t dstLen1, int8_t* dstBuf2,
size_t dstLen2, const int8_t* srcBuf1, size_t srcLen1,
const int8_t* srcBuf2, size_t srcLen2) {
// Caller should make sure the dst buffer has more space.
DCHECK_GE(dstLen1 + dstLen2, srcLen1 + srcLen2);
CopyDesc cp1 = {dstBuf1, srcBuf1, 0};
CopyDesc cp2;
CopyDesc cp3;
if (srcLen1 == dstLen1) {
cp1 = {dstBuf1, srcBuf1, srcLen1};
DCHECK_LE(srcLen2, dstLen2);
cp2 = {dstBuf2, srcBuf2, srcLen2};
// No need to copy more data, thus no need to update cp3.
} else if (srcLen1 < dstLen1) {
cp1 = {dstBuf1, srcBuf1, srcLen1};
if (dstLen1 <= srcLen1 + srcLen2) {
// Copy data into both dstBuf1 and dstBuf2.
cp2 = {cp1.dst + cp1.len, srcBuf2, dstLen1 - srcLen1};
cp3 = {dstBuf2, cp2.src + cp2.len, srcLen1 + srcLen2 - dstLen1};
} else {
// dstBuf1 is bigger enough to hold all the data from src.
cp2 = {cp1.dst + cp1.len, srcBuf2, srcLen2};
// No need to copy more data, thus no need to update cp3.
}
} else { // srcLen1 > dstLen1
cp1 = {dstBuf1, srcBuf1, dstLen1};
cp2 = {dstBuf2, cp1.src + cp1.len, srcLen1 - dstLen1};
cp3 = {cp2.dst + cp2.len, srcBuf2, srcLen2};
}
if (cp1.len > 0) {
DCHECK(cp1.dst);
DCHECK(cp1.src);
std::memcpy(cp1.dst, cp1.src, cp1.len);
}
if (cp2.len > 0) {
DCHECK(cp2.dst);
DCHECK(cp2.src);
std::memcpy(cp2.dst, cp2.src, cp2.len);
}
if (cp3.len > 0) {
DCHECK(cp3.dst);
DCHECK(cp3.src);
std::memcpy(cp3.dst, cp3.src, cp3.len);
}
}
} // namespace audio_proxy::service