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1 /*
2  * Copyright (c) 2023 Huawei Device 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 #ifndef AVSESSION_BASE64_UTILS_H
17 #define AVSESSION_BASE64_UTILS_H
18 
19 #include <cstring>
20 #include <string>
21 #include <iostream>
22 
23 namespace OHOS::AVSession {
24 class Base64Utils {
25 public:
Base64Encode(const char * data)26     static std::string Base64Encode(const char *data)
27     {
28         char out[MAX_LENGTH] = {0};
29         int dataLen = strlen(data);
30         if (dataLen == 0) {
31             out[0] = '\0';
32             return "";
33         }
34 
35         int index = 0;
36         char c = '\0';
37         char lastC = '\0';
38 
39         for (int i = 0; i < dataLen; i++) {
40             c = data[i];
41             switch (i % NUMBER_THREE) {
42                 case 0:
43                     out[index++] = BASE64_EN[(c >> NUMBER_TWO) & 0x3f];
44                     break;
45                 case 1:
46                     out[index++] = BASE64_EN[(lastC & 0x3) << NUMBER_FOUR | ((c >> NUMBER_FOUR) & 0xf)];
47                     break;
48                 case NUMBER_TWO:
49                     out[index++] = BASE64_EN[(lastC & 0xf) << NUMBER_TWO | ((c >> NUMBER_SIX) & 0x3)];
50                     out[index++] = BASE64_EN[c & 0x3f];
51                     break;
52                 default:
53                     break;
54             }
55             lastC = c;
56         }
57 
58         if (dataLen % NUMBER_THREE == NUMBER_ONE) {
59             out[index++] = BASE64_EN[(c & 0x3) << NUMBER_FOUR];
60             out[index++] = '=';
61             out[index++] = '=';
62         }
63 
64         if (dataLen % NUMBER_THREE == NUMBER_TWO) {
65             out[index++] = BASE64_EN[(c & 0xf) << NUMBER_TWO];
66             out[index++] = '=';
67         }
68         return std::string(out);
69 }
70 
71 private:
72     static constexpr const int MAX_LENGTH = 1024;
73     static constexpr const int NUMBER_ONE = 1;
74     static constexpr const int NUMBER_TWO = 2;
75     static constexpr const int NUMBER_THREE = 3;
76     static constexpr const int NUMBER_FOUR = 4;
77     static constexpr const int NUMBER_SIX = 6;
78     static constexpr const char BASE64_EN[] = {
79         'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
80         'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
81         'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
82         'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
83         's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2',
84         '3', '4', '5', '6', '7', '8', '9', '+', '/'
85     };
86 };
87 } // namespace OHOS::AVSession
88 
89 #endif // AVSESSION_BASE64_UTILS_H
90