1 /*
2  * Copyright (C) 2015-2020 Alibaba Group Holding Limited
3  */
4 
5 #include <stdio.h>
6 #include <stdint.h>
7 
8 static const unsigned char base64_encode_map[] = {
9     'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
10     'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
11     'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
12     'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
13     'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
14     'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
15     'w', 'x', 'y', 'z', '0', '1', '2', '3',
16     '4', '5', '6', '7', '8', '9', '+', '/'
17 };
18 
19 static const unsigned char base64_decode_map[] = {
20     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
21     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
22     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 62,  0,  0,  0, 63,
23     52, 53, 54, 55, 56, 57, 58, 59, 60, 61,  0,  0,  0,  0,  0,  0,
24     0,  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,  0,  0,  0,  0,  0,
26     0, 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,  0,  0,  0,  0,  0,
28     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
29     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
30     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
31     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
32     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
33     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
34     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
35     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0
36 };
37 
38 static const unsigned char mod_table[] = { 0, 2, 1 };
39 
uvoice_base64_encode(const uint8_t * input,uint32_t input_len,uint8_t * output,uint32_t * output_len)40 int uvoice_base64_encode(const uint8_t *input, uint32_t input_len, uint8_t *output, uint32_t *output_len)
41 {
42 	int i, j;
43 	uint32_t o_len = 4 * ((input_len + 2) / 3);
44 
45     if (!input || !output || !output_len) {
46         return -1;
47     }
48 
49     if (output_len)
50     {
51         *output_len = o_len;
52     }
53 
54     for (i = 0, j = 0; i < input_len;)
55     {
56         unsigned int octet_a = i < input_len ? input[i++] : 0;
57         unsigned int octet_b = i < input_len ? input[i++] : 0;
58         unsigned int octet_c = i < input_len ? input[i++] : 0;
59 
60         unsigned int triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
61 
62         output[j++] = base64_encode_map[(triple >> 18) & 0x3F];
63         output[j++] = base64_encode_map[(triple >> 12) & 0x3F];
64         output[j++] = base64_encode_map[(triple >> 6) & 0x3F];
65         output[j++] = base64_encode_map[(triple >> 0) & 0x3F];
66     }
67 
68     for (i = 0; i < mod_table[input_len % 3]; i++)
69     {
70         output[o_len - 1 - i] = '=';
71     }
72 
73     return 0;
74 }
75 
uvoice_basex64_decode(const uint8_t * input,uint32_t input_len,uint8_t * output,uint32_t * output_len)76 int uvoice_basex64_decode(const uint8_t* input, uint32_t input_len, uint8_t* output, uint32_t* output_len)
77 {
78     int i, j;
79     uint32_t o_len = input_len / 4 * 3;
80 
81     if (!input || !output || !output_len)
82     {
83         return -1;
84     }
85 
86     if (input[input_len - 1] == '=')
87     {
88         o_len--;
89     }
90     if (input[input_len - 2] == '=')
91     {
92         o_len--;
93     }
94 
95     if (output_len)
96     {
97         *output_len = o_len;
98     }
99 
100     for (i = 0, j = 0; i < input_len;)
101     {
102         unsigned int sextet_a = base64_decode_map[input[i++]];
103         unsigned int sextet_b = base64_decode_map[input[i++]];
104         unsigned int sextet_c = base64_decode_map[input[i++]];
105         unsigned int sextet_d = base64_decode_map[input[i++]];
106 
107         unsigned int triple = (sextet_a << 18)
108                               + (sextet_b << 12)
109                               + (sextet_c << 6)
110                               + (sextet_d << 0);
111 
112         if (j < o_len)
113         {
114             output[j++] = (triple >> 16) & 0xFF;
115         }
116         if (j < o_len)
117         {
118             output[j++] = (triple >> 8) & 0xFF;
119         }
120         if (j < o_len)
121         {
122             output[j++] = (triple >> 0) & 0xFF;
123         }
124     }
125 
126     return 0;
127 }
128