1 #include <libcper/base64.h> 2 #include <libcper/BaseTypes.h> 3 4 #include <stdlib.h> 5 #include <string.h> 6 #include <stdio.h> 7 #include <assert.h> 8 9 static const UINT8 encode_table[65] = 10 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 11 12 /** 13 * 14 * Caller is responsible for freeing the returned buffer. 15 */ 16 CHAR8 *base64_encode(const UINT8 *src, INT32 len, INT32 *out_len) 17 { 18 CHAR8 *out; 19 CHAR8 *out_pos; 20 const UINT8 *src_end; 21 const UINT8 *in_pos; 22 23 if (len <= 0) { 24 return NULL; 25 } 26 27 if (!out_len) { 28 return NULL; 29 } 30 31 // 3 byte blocks to 4 byte blocks plus up to 2 bytes of padding 32 *out_len = 4 * ((len + 2) / 3); 33 34 // Handle overflows 35 if (*out_len < len) { 36 return NULL; 37 } 38 39 out = malloc(*out_len); 40 if (out == NULL) { 41 return NULL; 42 } 43 44 src_end = src + len; 45 in_pos = src; 46 out_pos = out; 47 while (src_end - in_pos >= 3) { 48 *out_pos++ = encode_table[in_pos[0] >> 2]; 49 *out_pos++ = encode_table[((in_pos[0] & 0x03) << 4) | 50 (in_pos[1] >> 4)]; 51 *out_pos++ = encode_table[((in_pos[1] & 0x0f) << 2) | 52 (in_pos[2] >> 6)]; 53 *out_pos++ = encode_table[in_pos[2] & 0x3f]; 54 in_pos += 3; 55 } 56 57 if (src_end - in_pos) { 58 *out_pos++ = encode_table[in_pos[0] >> 2]; 59 if (src_end - in_pos == 1) { 60 *out_pos++ = encode_table[(in_pos[0] & 0x03) << 4]; 61 *out_pos++ = '='; 62 } else { 63 *out_pos++ = encode_table[((in_pos[0] & 0x03) << 4) | 64 (in_pos[1] >> 4)]; 65 *out_pos++ = encode_table[(in_pos[1] & 0x0f) << 2]; 66 } 67 *out_pos++ = '='; 68 } 69 70 return out; 71 } 72 73 // Base64 decode table. Invalid values are specified with 0x80. 74 UINT8 decode_table[256] = 75 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 76 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 77 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x3e\x80\x80\x80\x3f" 78 "\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x80\x80\x80\x00\x80\x80" 79 "\x80\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e" 80 "\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x80\x80\x80\x80\x80" 81 "\x80\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27\x28" 82 "\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x80\x80\x80\x80\x80" 83 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 84 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 85 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 86 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 87 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 88 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 89 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80" 90 "\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80"; 91 92 /** 93 * 94 * Caller is responsible for freeing the returned buffer. 95 */ 96 UINT8 *base64_decode(const CHAR8 *src, INT32 len, INT32 *out_len) 97 { 98 UINT8 *out; 99 UINT8 *pos; 100 UINT8 block[4]; 101 UINT8 tmp; 102 INT32 block_index; 103 INT32 src_index; 104 UINT32 pad_count = 0; 105 106 if (!out_len) { 107 return NULL; 108 } 109 110 // Malloc might be up to 2 larger dependent on padding 111 *out_len = len / 4 * 3; 112 pos = out = malloc(*out_len); 113 if (out == NULL) { 114 return NULL; 115 } 116 117 block_index = 0; 118 for (src_index = 0; src_index < len; src_index++) { 119 tmp = decode_table[(UINT8)src[src_index]]; 120 if (tmp == 0x80) { 121 free(out); 122 return NULL; 123 } 124 125 if (src[src_index] == '=') { 126 pad_count++; 127 } 128 129 block[block_index] = tmp; 130 block_index++; 131 if (block_index == 4) { 132 *pos++ = (block[0] << 2) | (block[1] >> 4); 133 *pos++ = (block[1] << 4) | (block[2] >> 2); 134 *pos++ = (block[2] << 6) | block[3]; 135 if (pad_count > 0) { 136 if (pad_count == 1) { 137 pos--; 138 } else if (pad_count == 2) { 139 pos -= 2; 140 } else { 141 /* Invalid pad_counting */ 142 free(out); 143 return NULL; 144 } 145 break; 146 } 147 block_index = 0; 148 } 149 } 150 151 *out_len = pos - out; 152 return out; 153 } 154