1 /*
2 * Copyright (C) 2018 BlueKitchen GmbH
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the copyright holders nor the names of
14 * contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * 4. Any redistribution, use, or modification is done solely for
17 * personal benefit and not for any commercial purpose or for
18 * monetary gain.
19 *
20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * Please inquire about commercial licensing options at
34 * [email protected]
35 *
36 */
37
38 #define BTSTACK_FILE__ "btstack_base64_decoder.c"
39
40 /*
41 * btstack_base64_decoder.c
42 */
43
44 #include "btstack_base64_decoder.h"
45 #include "btstack_debug.h"
46 #include <string.h>
47
48 /**
49 * @brief Initialize base99 decoder
50 * @param context
51 */
btstack_base64_decoder_init(btstack_base64_decoder_t * context)52 void btstack_base64_decoder_init(btstack_base64_decoder_t * context){
53 memset(context, 0, sizeof(btstack_base64_decoder_t));
54 }
55
56 /**
57 * @brief Decode single byte
58 * @param context
59 * @return value, or BTSTACK_BASE64_DECODER_COMPLETE, BTSTACK_BASE64_DECODER_INVALID
60 */
btstack_base64_decoder_process_byte(btstack_base64_decoder_t * context,uint8_t c)61 int btstack_base64_decoder_process_byte(btstack_base64_decoder_t * context, uint8_t c){
62
63 // map ascii char to 6-bit value
64 static const uint8_t table[256] = {
65 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
66 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
67 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 62, 99, 99, 99, 63,
68 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 99, 99, 99, 99, 99, 99,
69 99, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
70 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 99, 99, 99, 99, 99,
71 99, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
72 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 99, 99, 99, 99, 99,
73 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
74 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
75 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
76 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
77 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
78 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
79 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
80 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99
81 };
82
83 // handle '='
84 if (c == '='){
85 if ((context->pos == 2u) || (context->pos == 3u)){
86 context->pos++;
87 return BTSTACK_BASE64_DECODER_MORE;
88 }
89 }
90
91 // lookup
92 uint8_t value = table[c];
93
94 // invalid character
95 if (value == 99u) {
96 context->pos = 99;
97 }
98
99 int result = 0;
100 switch (context->pos){
101 case 0:
102 context->value = value; // 6 bit
103 context->pos++;
104 result = BTSTACK_BASE64_DECODER_MORE;
105 break;
106 case 1:
107 result = (context->value << 2) | (value >> 4);
108 context->value = value; // 4 bit
109 context->pos++;
110 break;
111 case 2:
112 result = (context->value << 4) | (value >> 2);
113 context->value = value; // 2 bit
114 context->pos++;
115 break;
116 case 3:
117 result = (context->value << 6) | value;
118 context->pos = 0; // done
119 break;
120 case 99:
121 result = BTSTACK_BASE64_DECODER_INVALID;
122 break;
123 default:
124 btstack_assert(false);
125 break;
126 }
127 return result;
128 }
129
btstack_base64_decoder_process_block(const uint8_t * input_data,uint32_t input_size,uint8_t * output_buffer,uint32_t output_max_size)130 int btstack_base64_decoder_process_block(const uint8_t * input_data, uint32_t input_size, uint8_t * output_buffer, uint32_t output_max_size){
131 btstack_base64_decoder_t context;
132 btstack_base64_decoder_init(&context);
133 uint32_t size = 0;
134 while (input_size){
135 uint8_t data = *input_data++;
136 int result = btstack_base64_decoder_process_byte(&context, data);
137 input_size--;
138 switch (result){
139 case BTSTACK_BASE64_DECODER_MORE:
140 break;
141 case BTSTACK_BASE64_DECODER_INVALID:
142 return BTSTACK_BASE64_DECODER_INVALID;
143 default:
144 if (size >= output_max_size){
145 return BTSTACK_BASE64_DECODER_FULL;
146 }
147 output_buffer[size++] = result;
148 break;
149 }
150 }
151 return size;
152 }
153