1 /*
2 * Copyright (c) 2023 Shenzhen Kaihong Digital Industry Development Co., Ltd.
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
16 #include "h264_frame.h"
17 #include "common/sharing_log.h"
18
19 namespace OHOS {
20 namespace Sharing {
PrefixSize(const char * ptr,size_t len)21 size_t PrefixSize(const char *ptr, size_t len)
22 {
23 if (len < 4) { // 4:byte offset
24 return 0;
25 }
26 if (ptr[0] != 0x00 || ptr[1] != 0x00) {
27 return 0;
28 }
29 if (ptr[2] == 0x00 && ptr[3] == 0x01) { // 2:byte offset, 3:byte offset
30 return 4; // 4:prefix size
31 }
32 if (ptr[2] == 0x01) { // 2:byte offset
33 return 3; // 3:prefix size
34 }
35
36 return 0;
37 }
38
MemFind(const char * buf,ssize_t len,const char * subBuf,ssize_t subLen)39 static const char *MemFind(const char *buf, ssize_t len, const char *subBuf, ssize_t subLen)
40 {
41 for (auto i = 0; i < len - subLen; ++i) {
42 if (memcmp(buf + i, subBuf, subLen) == 0) {
43 return buf + i;
44 }
45 }
46
47 return NULL;
48 }
49
SplitH264(const char * ptr,size_t len,size_t prefix,const std::function<void (const char *,size_t,size_t)> & cb)50 void SplitH264(const char *ptr, size_t len, size_t prefix, const std::function<void(const char *, size_t, size_t)> &cb)
51 {
52 if (prefix <= 0) {
53 prefix = PrefixSize(ptr, len);
54 }
55 auto start = ptr + prefix;
56 auto end = ptr + len;
57 size_t nextPrefix;
58 while (true) {
59 auto nextStart = MemFind(start, end - start, "\x00\x00\x01", 3);
60 if (nextStart) {
61 if (*(nextStart - 1) == 0x00) {
62 nextStart -= 1;
63 nextPrefix = 4; // 4:prefix size
64 } else {
65 nextPrefix = 3; // 3:prefix size
66 }
67
68 cb(start - prefix, nextStart - start + prefix, prefix);
69
70 start = nextStart + nextPrefix;
71
72 prefix = nextPrefix;
73 continue;
74 }
75
76 cb(start - prefix, end - start + prefix, prefix);
77 break;
78 }
79 }
80 } // namespace Sharing
81 } // namespace OHOS