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 MATTHIAS 24 * RINGWALD 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 /* 39 * btstack_base64_decoder.c 40 */ 41 42 #include "btstack_base64_decoder.h" 43 #include <string.h> 44 #include <stdio.h> 45 46 // map ascii char to 6-bit value 47 static const uint8_t table[256] = { 48 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 49 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 50 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 62, 99, 99, 99, 63, 51 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 99, 99, 99, 99, 99, 99, 52 99, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 53 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 99, 99, 99, 99, 99, 54 99, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 55 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 99, 99, 99, 99, 99, 56 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 57 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 58 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 59 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 60 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 61 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 62 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 63 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99 64 }; 65 66 /** 67 * @brief Initialize base99 decoder 68 * @param context 69 */ 70 void btstack_base64_decoder_init(btstack_base64_decoder_t * context){ 71 memset(context, 0, sizeof(btstack_base64_decoder_t)); 72 } 73 74 /** 75 * @brief Decode single byte 76 * @param context 77 * @returns value, or BTSTACK_BASE64_DECODER_COMPLETE, BTSTACK_BASE64_DECODER_INVALID 78 */ 79 int btstack_base64_decoder_process_byte(btstack_base64_decoder_t * context, uint8_t c){ 80 81 // handle '=' 82 if (c == '='){ 83 if (context->pos == 2 || context->pos == 3){ 84 context->pos++; 85 return BTSTACK_BASE64_DECODER_MORE; 86 } 87 } 88 89 // lookup 90 uint8_t value = table[c]; 91 92 // invalid character 93 if (value == 99) { 94 context->pos = 99; 95 } 96 97 int result = 0; 98 switch (context->pos){ 99 case 0: 100 context->value = value; // 6 bit 101 context->pos++; 102 result = BTSTACK_BASE64_DECODER_MORE; 103 break; 104 case 1: 105 result = (context->value << 2) | (value >> 4); 106 context->value = value; // 4 bit 107 context->pos++; 108 break; 109 case 2: 110 result = (context->value << 4) | (value >> 2); 111 context->value = value; // 2 bit 112 context->pos++; 113 break; 114 case 3: 115 result = (context->value << 6) | value; 116 context->pos = 0; // done 117 break; 118 case 99: 119 result = BTSTACK_BASE64_DECODER_INVALID; 120 break; 121 } 122 return result; 123 } 124 125 int btstack_base64_decoder_process_block(const uint8_t * input_data, uint32_t input_size, uint8_t * output_buffer, uint32_t output_max_size){ 126 btstack_base64_decoder_t context; 127 btstack_base64_decoder_init(&context); 128 uint32_t size = 0; 129 while (input_size){ 130 uint8_t data = *input_data++; 131 int result = btstack_base64_decoder_process_byte(&context, data); 132 input_size--; 133 switch (result){ 134 case BTSTACK_BASE64_DECODER_MORE: 135 break; 136 case BTSTACK_BASE64_DECODER_INVALID: 137 return BTSTACK_BASE64_DECODER_INVALID; 138 default: 139 if (size >= output_max_size){ 140 return BTSTACK_BASE64_DECODER_FULL; 141 } 142 output_buffer[size++] = result; 143 break; 144 } 145 } 146 return size; 147 } 148