Cataract Gemuese / sose2016_tr_oauth_pop

The Ethernet-Board

Dependencies:   EthernetInterface HTTPClient MODSERIAL mbed-dev mbed-rtos wolfSSL

Fork of sose2016_tr_oauth_pop by niko gillen

base64.cpp@7:5d116f2e5587, 2016-07-12 (annotated)

Committer:
Cataract
Date:
Tue Jul 12 15:25:26 2016 +0000
Revision:
7:5d116f2e5587
final commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Cataract 7:5d116f2e5587 1 #include <stdint.h>
Cataract 7:5d116f2e5587 2 #include <stdlib.h>
Cataract 7:5d116f2e5587 3
Cataract 7:5d116f2e5587 4
Cataract 7:5d116f2e5587 5 static char encoding_table[] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
Cataract 7:5d116f2e5587 6 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
Cataract 7:5d116f2e5587 7 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
Cataract 7:5d116f2e5587 8 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
Cataract 7:5d116f2e5587 9 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
Cataract 7:5d116f2e5587 10 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
Cataract 7:5d116f2e5587 11 'w', 'x', 'y', 'z', '0', '1', '2', '3',
Cataract 7:5d116f2e5587 12 '4', '5', '6', '7', '8', '9', '-', '_'};
Cataract 7:5d116f2e5587 13 static char *decoding_table = NULL;
Cataract 7:5d116f2e5587 14 static int mod_table[] = {0, 2, 1};
Cataract 7:5d116f2e5587 15
Cataract 7:5d116f2e5587 16
Cataract 7:5d116f2e5587 17 void build_decoding_table() {
Cataract 7:5d116f2e5587 18
Cataract 7:5d116f2e5587 19 decoding_table = (char*) malloc(256);
Cataract 7:5d116f2e5587 20
Cataract 7:5d116f2e5587 21 for (int i = 0; i < 64; i++)
Cataract 7:5d116f2e5587 22 decoding_table[(unsigned char) encoding_table[i]] = i;
Cataract 7:5d116f2e5587 23 }
Cataract 7:5d116f2e5587 24
Cataract 7:5d116f2e5587 25
Cataract 7:5d116f2e5587 26 void base64_cleanup() {
Cataract 7:5d116f2e5587 27 free(decoding_table);
Cataract 7:5d116f2e5587 28 }
Cataract 7:5d116f2e5587 29
Cataract 7:5d116f2e5587 30 char *base64_encode(const unsigned char *data,
Cataract 7:5d116f2e5587 31 size_t input_length,
Cataract 7:5d116f2e5587 32 size_t *output_length) {
Cataract 7:5d116f2e5587 33
Cataract 7:5d116f2e5587 34 *output_length = 4 * ((input_length +2) / 3);
Cataract 7:5d116f2e5587 35
Cataract 7:5d116f2e5587 36 char *encoded_data = (char*) malloc(*output_length);
Cataract 7:5d116f2e5587 37 if (encoded_data == NULL) return NULL;
Cataract 7:5d116f2e5587 38
Cataract 7:5d116f2e5587 39 for (int i = 0, j = 0; i < input_length;) {
Cataract 7:5d116f2e5587 40
Cataract 7:5d116f2e5587 41 uint32_t octet_a = i < input_length ? (unsigned char)data[i++] : 0;
Cataract 7:5d116f2e5587 42 uint32_t octet_b = i < input_length ? (unsigned char)data[i++] : 0;
Cataract 7:5d116f2e5587 43 uint32_t octet_c = i < input_length ? (unsigned char)data[i++] : 0;
Cataract 7:5d116f2e5587 44
Cataract 7:5d116f2e5587 45 uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
Cataract 7:5d116f2e5587 46
Cataract 7:5d116f2e5587 47 encoded_data[j++] = encoding_table[(triple >> 3 * 6) & 0x3F];
Cataract 7:5d116f2e5587 48 encoded_data[j++] = encoding_table[(triple >> 2 * 6) & 0x3F];
Cataract 7:5d116f2e5587 49 encoded_data[j++] = encoding_table[(triple >> 1 * 6) & 0x3F];
Cataract 7:5d116f2e5587 50 encoded_data[j++] = encoding_table[(triple >> 0 * 6) & 0x3F];
Cataract 7:5d116f2e5587 51 }
Cataract 7:5d116f2e5587 52
Cataract 7:5d116f2e5587 53 for (int i = 0; i < mod_table[input_length % 3]; i++)
Cataract 7:5d116f2e5587 54 encoded_data[*output_length - 1 - i] = 0x00;
Cataract 7:5d116f2e5587 55
Cataract 7:5d116f2e5587 56 return encoded_data;
Cataract 7:5d116f2e5587 57 }
Cataract 7:5d116f2e5587 58
Cataract 7:5d116f2e5587 59
Cataract 7:5d116f2e5587 60 unsigned char *base64_decode(const char *data,
Cataract 7:5d116f2e5587 61 size_t input_length,
Cataract 7:5d116f2e5587 62 size_t *output_length) {
Cataract 7:5d116f2e5587 63
Cataract 7:5d116f2e5587 64 if (decoding_table == NULL) build_decoding_table();
Cataract 7:5d116f2e5587 65
Cataract 7:5d116f2e5587 66 if (input_length % 4 != 0) return NULL;
Cataract 7:5d116f2e5587 67
Cataract 7:5d116f2e5587 68 *output_length = input_length / 4 * 3;
Cataract 7:5d116f2e5587 69 if (data[input_length - 1] == '=') (*output_length)--;
Cataract 7:5d116f2e5587 70 if (data[input_length - 2] == '=') (*output_length)--;
Cataract 7:5d116f2e5587 71
Cataract 7:5d116f2e5587 72 unsigned char *decoded_data = (unsigned char*) malloc(*output_length);
Cataract 7:5d116f2e5587 73 if (decoded_data == NULL) return NULL;
Cataract 7:5d116f2e5587 74
Cataract 7:5d116f2e5587 75 for (int i = 0, j = 0; i < input_length;) {
Cataract 7:5d116f2e5587 76
Cataract 7:5d116f2e5587 77 uint32_t sextet_a = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
Cataract 7:5d116f2e5587 78 uint32_t sextet_b = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
Cataract 7:5d116f2e5587 79 uint32_t sextet_c = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
Cataract 7:5d116f2e5587 80 uint32_t sextet_d = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
Cataract 7:5d116f2e5587 81
Cataract 7:5d116f2e5587 82 uint32_t triple = (sextet_a << 3 * 6)
Cataract 7:5d116f2e5587 83 + (sextet_b << 2 * 6)
Cataract 7:5d116f2e5587 84 + (sextet_c << 1 * 6)
Cataract 7:5d116f2e5587 85 + (sextet_d << 0 * 6);
Cataract 7:5d116f2e5587 86
Cataract 7:5d116f2e5587 87 if (j < *output_length) decoded_data[j++] = (triple >> 2 * 8) & 0xFF;
Cataract 7:5d116f2e5587 88 if (j < *output_length) decoded_data[j++] = (triple >> 1 * 8) & 0xFF;
Cataract 7:5d116f2e5587 89 if (j < *output_length) decoded_data[j++] = (triple >> 0 * 8) & 0xFF;
Cataract 7:5d116f2e5587 90 }
Cataract 7:5d116f2e5587 91
Cataract 7:5d116f2e5587 92 return decoded_data;
Cataract 7:5d116f2e5587 93 }