1 /**
2 * Copyright (c) 2006-2018 Apple Inc. All rights reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 **/
16
17 #include "base64.h"
18
19 #include <stdlib.h>
20 #include <string.h>
21
22 // base64 tables
23 static char basis_64[] =
24 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
25 static signed char index_64[128] =
26 {
27 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
28 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
29 -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
30 52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1,-1,-1,-1,
31 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
32 15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
33 -1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
34 41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
35 };
36 #define CHAR64(c) (((c) < 0 || (c) > 127) ? -1 : index_64[(c)])
37
38 // base64_encode : base64 encode
39 //
40 // value : data to encode
41 // vlen : length of data
42 // (result) : new char[] - c-str of result
base64_encode(const unsigned char * value,size_t vlen)43 char *base64_encode(const unsigned char *value, size_t vlen)
44 {
45 char *result = (char *)malloc((vlen * 4) / 3 + 5);
46 if (result == NULL)
47 {
48 return NULL;
49 }
50 char *out = result;
51 while (vlen >= 3)
52 {
53 *out++ = basis_64[value[0] >> 2];
54 *out++ = basis_64[((value[0] << 4) & 0x30) | (value[1] >> 4)];
55 *out++ = basis_64[((value[1] << 2) & 0x3C) | (value[2] >> 6)];
56 *out++ = basis_64[value[2] & 0x3F];
57 value += 3;
58 vlen -= 3;
59 }
60 if (vlen > 0)
61 {
62 *out++ = basis_64[value[0] >> 2];
63 unsigned char oval = (value[0] << 4) & 0x30;
64 if (vlen > 1) oval |= value[1] >> 4;
65 *out++ = basis_64[oval];
66 *out++ = (vlen < 2) ? '=' : basis_64[(value[1] << 2) & 0x3C];
67 *out++ = '=';
68 }
69 *out = '\0';
70
71 return result;
72 }
73
74 // base64_decode : base64 decode
75 //
76 // value : c-str to decode
77 // rlen : length of decoded result
78 // (result) : new unsigned char[] - decoded result
base64_decode(const char * value,size_t * rlen)79 unsigned char *base64_decode(const char *value, size_t *rlen)
80 {
81 *rlen = 0;
82 int c1, c2, c3, c4;
83
84 size_t vlen = strlen(value);
85 unsigned char *result =(unsigned char *)malloc((vlen * 3) / 4 + 1);
86 if (result == NULL)
87 {
88 return NULL;
89 }
90 unsigned char *out = result;
91
92 while (1) {
93 if (value[0]==0) {
94 return result;
95 }
96 c1 = value[0];
97 if (CHAR64(c1) == -1) {
98 goto base64_decode_error;;
99 }
100 c2 = value[1];
101 if (CHAR64(c2) == -1) {
102 goto base64_decode_error;;
103 }
104 c3 = value[2];
105 if ((c3 != '=') && (CHAR64(c3) == -1)) {
106 goto base64_decode_error;;
107 }
108 c4 = value[3];
109 if ((c4 != '=') && (CHAR64(c4) == -1)) {
110 goto base64_decode_error;;
111 }
112
113 value += 4;
114 *out++ = (CHAR64(c1) << 2) | (CHAR64(c2) >> 4);
115 *rlen += 1;
116
117 if (c3 != '=') {
118 *out++ = ((CHAR64(c2) << 4) & 0xf0) | (CHAR64(c3) >> 2);
119 *rlen += 1;
120
121 if (c4 != '=') {
122 *out++ = ((CHAR64(c3) << 6) & 0xc0) | CHAR64(c4);
123 *rlen += 1;
124 }
125 }
126 }
127
128 base64_decode_error:
129 *result = 0;
130 *rlen = 0;
131
132 return result;
133 }
134