27     255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
44     uint32_t i = 0;  in Decode()  local
61             // 2: shift 2bits, 4: shift 4bits  in Decode()
62             strDecode[i] = (base64Char[0] << 2) | ((base64Char[1] & 0x30) >> 4);  in Decode()
63             // 2: shift 2bits, 4: shift 4bits  in Decode()
64             strDecode[i + 1] = (base64Char[1] << 4) | ((base64Char[2] & 0x3c) >> 2);  in Decode()
65             // 2: shift 2bits, 3: the last encode str, 6: shift 6bits  in Decode()
66             strDecode[i + 2] = (base64Char[2] << 6) | base64Char[3];  in Decode()
68             i += DECODE_STR_LEN;  in Decode()
96     uint32_t i = 0;  in Encode()  local
102     while (i + 3 < encodeLen) { // 3: the last encode str  in Encode()
103         index = src[j] >> 2; // 2: shift 2bits  in Encode()
104         strEncode[i] = encodeMap[index];  in Encode()
106         strEncode[i + 1] = encodeMap[index];  in Encode()
107         index = ((src[j + 1] & 0x0F) << 2) | (src[j + 2] >> 6); // 2: shift 2bits, 6: shift 6bits  in Encode()
108         strEncode[i + 2] = encodeMap[index]; // 2: the second char  in Encode()
109         index = src[j + 2] & 0x3F; // 2: the second char  in Encode()
110         strEncode[i + 3] = encodeMap[index]; // 3: the third char  in Encode()
112         i += ENCODE_STR_LEN;  in Encode()
118     } else if (equalsCnt == 2) { // 2: Equal's count  in Encode()
120         strEncode[encodeLen - 2] = '='; // 2: the last two chars  in Encode()