1 /*
2 * Copyright (c) 2022 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 #include "base/pt_base64.h"
17
18 namespace panda::ecmascript::tooling {
19 static const unsigned char DECODE_TABLE[] = {
20 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
21 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
22 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
23 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 255, 255, 255,
24 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
25 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255,
26 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
27 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 255, 255, 255, 255, 255,
28 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
29 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
30 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
31 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
32 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
33 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
34 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
35 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
36 };
37
38 static const char ENCODE_TABLE[] = {
39 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
40 "abcdefghijklmnopqrstuvwxyz"
41 "0123456789+/"
42 };
43
Decode(void * output,const char * input,std::size_t len)44 std::pair<std::size_t, bool> PtBase64::Decode(void *output, const char *input, std::size_t len)
45 {
46 if (len < ENCODED_GROUP_BYTES || len % ENCODED_GROUP_BYTES != 0) {
47 return {0, false};
48 }
49
50 auto *src = reinterpret_cast<unsigned char const *>(input);
51 char *dest = static_cast<char *>(output);
52 char base64Chars[ENCODED_GROUP_BYTES];
53 int8_t i = 0;
54 while (len-- && *src != '=') {
55 auto v = DECODE_TABLE[*src];
56 if (v == INVAILD_VALUE) {
57 break;
58 }
59 base64Chars[i++] = v;
60
61 if (i == ENCODED_GROUP_BYTES) {
62 *dest++ = (base64Chars[0] << 2) | ((base64Chars[1] & 0x30) >> 4); // 2: shift 2bits, 4: shift 4bits
63 *dest++ = (base64Chars[1] << 4) | ((base64Chars[2] & 0x3c) >> 2); // 2: shift 2bits, 4: shift 4bits
64 *dest++ = (base64Chars[2] << 6) | base64Chars[3]; // 6: shift 6bits, 2: the second char, 3: the third char
65 i = 0;
66 }
67 src++;
68 }
69
70 if (i != 0) {
71 char tmp[UNENCODED_GROUP_BYTES];
72 tmp[0] = (base64Chars[0] << 2) | ((base64Chars[1] & 0x30) >> 4); // 2: shift 2bits, 4: shift 4bits
73 tmp[1] = (base64Chars[1] << 4) | ((base64Chars[2] & 0x3c) >> 2); // 2: shift 2bits, 4: shift 4bits
74 tmp[2] = (base64Chars[2] << 6) | base64Chars[3]; // 6: shift 6bits, 2: the second char, 3: the third char
75 for (int8_t j = 0; j < i - 1; j++) {
76 *dest++ = tmp[j];
77 }
78 }
79
80 len++; // get the remaining length and also avoid underflow
81 size_t decodedLen = dest - static_cast<char *>(output);
82 bool decodedDone = false;
83 // 0: decodedDone, 1: =, 2: ==
84 if (len == 0 || (len == 1 && *src == '=') || (len == 2 && *src == '=' && *(src + 1) == '=')) {
85 decodedDone = true;
86 }
87
88 return {decodedLen, decodedDone};
89 }
90
Encode(char * output,const void * input,std::size_t len)91 size_t PtBase64::Encode(char *output, const void *input, std::size_t len)
92 {
93 if (len == 0) {
94 return 0;
95 }
96
97 auto *src = static_cast<const unsigned char *>(input);
98 char *dest = output;
99 for (auto n = len / UNENCODED_GROUP_BYTES; n--;) {
100 *dest++ = ENCODE_TABLE[src[0] >> 2]; // 2: shift 2bits
101 *dest++ = ENCODE_TABLE[((src[0] & 0x03) << 4) | (src[1] >> 4)]; // 4: shift 4bits
102 *dest++ = ENCODE_TABLE[((src[1] & 0x0f) << 2) | (src[2] >> 6)]; // 2: shift 2bits, 6: shift 6bits
103 *dest++ = ENCODE_TABLE[src[2] & 0x3f]; // 2: the second char
104
105 src += UNENCODED_GROUP_BYTES;
106 }
107
108 int8_t remainder = static_cast<int8_t>(len % UNENCODED_GROUP_BYTES);
109 int8_t paddingCnt = (UNENCODED_GROUP_BYTES - remainder) % UNENCODED_GROUP_BYTES;
110 switch (paddingCnt) {
111 case 1:
112 *dest++ = ENCODE_TABLE[src[0] >> 2]; // 2: shift 2bits
113 *dest++ = ENCODE_TABLE[((src[0] & 0x03) << 4) | (src[1] >> 4)]; // 4: shift 4bits
114 *dest++ = ENCODE_TABLE[((src[1] & 0x0f) << 2)]; // 2: shift 2bits
115 *dest++ = '=';
116 break;
117 case 2: // 2: "=="
118 *dest++ = ENCODE_TABLE[src[0] >> 2]; // 2: shift 2bits
119 *dest++ = ENCODE_TABLE[((src[0] & 0x03) << 4)]; // 4: shift 4bits
120 *dest++ = '=';
121 *dest++ = '=';
122 break;
123 default:
124 break;
125 }
126 return dest - output;
127 }
128 } // namespace panda::ecmascript::tooling