1 // Copyright (C) 2021 The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include "RingBufferUtil.h"
16
17 #include <android-base/logging.h>
18
19 namespace audio_proxy::service {
20 namespace {
21 struct CopyDesc {
22 int8_t* dst = nullptr;
23 const int8_t* src = nullptr;
24 size_t len = 0;
25 };
26 } // namespace
27
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)28 void copyRingBuffer(int8_t* dstBuf1, size_t dstLen1, int8_t* dstBuf2,
29 size_t dstLen2, const int8_t* srcBuf1, size_t srcLen1,
30 const int8_t* srcBuf2, size_t srcLen2) {
31 // Caller should make sure the dst buffer has more space.
32 DCHECK_GE(dstLen1 + dstLen2, srcLen1 + srcLen2);
33
34 CopyDesc cp1 = {dstBuf1, srcBuf1, 0};
35 CopyDesc cp2;
36 CopyDesc cp3;
37
38 if (srcLen1 == dstLen1) {
39 cp1 = {dstBuf1, srcBuf1, srcLen1};
40
41 DCHECK_LE(srcLen2, dstLen2);
42 cp2 = {dstBuf2, srcBuf2, srcLen2};
43
44 // No need to copy more data, thus no need to update cp3.
45 } else if (srcLen1 < dstLen1) {
46 cp1 = {dstBuf1, srcBuf1, srcLen1};
47
48 if (dstLen1 <= srcLen1 + srcLen2) {
49 // Copy data into both dstBuf1 and dstBuf2.
50 cp2 = {cp1.dst + cp1.len, srcBuf2, dstLen1 - srcLen1};
51 cp3 = {dstBuf2, cp2.src + cp2.len, srcLen1 + srcLen2 - dstLen1};
52 } else {
53 // dstBuf1 is bigger enough to hold all the data from src.
54 cp2 = {cp1.dst + cp1.len, srcBuf2, srcLen2};
55
56 // No need to copy more data, thus no need to update cp3.
57 }
58 } else { // srcLen1 > dstLen1
59 cp1 = {dstBuf1, srcBuf1, dstLen1};
60 cp2 = {dstBuf2, cp1.src + cp1.len, srcLen1 - dstLen1};
61 cp3 = {cp2.dst + cp2.len, srcBuf2, srcLen2};
62 }
63
64 if (cp1.len > 0) {
65 DCHECK(cp1.dst);
66 DCHECK(cp1.src);
67 std::memcpy(cp1.dst, cp1.src, cp1.len);
68 }
69
70 if (cp2.len > 0) {
71 DCHECK(cp2.dst);
72 DCHECK(cp2.src);
73 std::memcpy(cp2.dst, cp2.src, cp2.len);
74 }
75
76 if (cp3.len > 0) {
77 DCHECK(cp3.dst);
78 DCHECK(cp3.src);
79 std::memcpy(cp3.dst, cp3.src, cp3.len);
80 }
81 }
82
83 } // namespace audio_proxy::service