David Smart / SW_HTTPServer

A simple web server that can be bound to either the EthernetInterface or the WiflyInterface.

Dependents:   Smart-WiFly-WebServer WattEye X10Svr SSDP_Server

Base64.cpp@12:109bf1558300, 2013-08-11 (annotated)

Committer:
WiredHome
Date:
Sun Aug 11 15:49:51 2013 +0000
Revision:
12:109bf1558300
Child:
13:8975d7928678
Added Base64 encode/decode, but not yet implementing it.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
WiredHome 12:109bf1558300 1
WiredHome 12:109bf1558300 2 #include "mbed.h"
WiredHome 12:109bf1558300 3 #include "Base64.h"
WiredHome 12:109bf1558300 4
WiredHome 12:109bf1558300 5 static const char encoding_table[] = {
WiredHome 12:109bf1558300 6 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
WiredHome 12:109bf1558300 7 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
WiredHome 12:109bf1558300 8 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
WiredHome 12:109bf1558300 9 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
WiredHome 12:109bf1558300 10 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
WiredHome 12:109bf1558300 11 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
WiredHome 12:109bf1558300 12 'w', 'x', 'y', 'z', '0', '1', '2', '3',
WiredHome 12:109bf1558300 13 '4', '5', '6', '7', '8', '9', '+', '/'
WiredHome 12:109bf1558300 14 };
WiredHome 12:109bf1558300 15
WiredHome 12:109bf1558300 16 static const int mod_table[] = {0, 2, 1};
WiredHome 12:109bf1558300 17
WiredHome 12:109bf1558300 18 Base64::Base64()
WiredHome 12:109bf1558300 19 {
WiredHome 12:109bf1558300 20 decoding_table = NULL;
WiredHome 12:109bf1558300 21 }
WiredHome 12:109bf1558300 22
WiredHome 12:109bf1558300 23 Base64::~Base64()
WiredHome 12:109bf1558300 24 {
WiredHome 12:109bf1558300 25 if (decoding_table)
WiredHome 12:109bf1558300 26 free(decoding_table);
WiredHome 12:109bf1558300 27 }
WiredHome 12:109bf1558300 28
WiredHome 12:109bf1558300 29
WiredHome 12:109bf1558300 30 char * Base64::base64_encode(const unsigned char *data,size_t input_length,size_t *output_length)
WiredHome 12:109bf1558300 31 {
WiredHome 12:109bf1558300 32 *output_length = 4 * ((input_length + 2) / 3);
WiredHome 12:109bf1558300 33
WiredHome 12:109bf1558300 34 char *encoded_data = (char *)malloc(*output_length);
WiredHome 12:109bf1558300 35 if (encoded_data == NULL) return NULL;
WiredHome 12:109bf1558300 36
WiredHome 12:109bf1558300 37 for (int i = 0, j = 0; i < input_length;) {
WiredHome 12:109bf1558300 38
WiredHome 12:109bf1558300 39 uint32_t octet_a = i < input_length ? data[i++] : 0;
WiredHome 12:109bf1558300 40 uint32_t octet_b = i < input_length ? data[i++] : 0;
WiredHome 12:109bf1558300 41 uint32_t octet_c = i < input_length ? data[i++] : 0;
WiredHome 12:109bf1558300 42
WiredHome 12:109bf1558300 43 uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
WiredHome 12:109bf1558300 44
WiredHome 12:109bf1558300 45 encoded_data[j++] = encoding_table[(triple >> 3 * 6) & 0x3F];
WiredHome 12:109bf1558300 46 encoded_data[j++] = encoding_table[(triple >> 2 * 6) & 0x3F];
WiredHome 12:109bf1558300 47 encoded_data[j++] = encoding_table[(triple >> 1 * 6) & 0x3F];
WiredHome 12:109bf1558300 48 encoded_data[j++] = encoding_table[(triple >> 0 * 6) & 0x3F];
WiredHome 12:109bf1558300 49 }
WiredHome 12:109bf1558300 50
WiredHome 12:109bf1558300 51 for (int i = 0; i < mod_table[input_length % 3]; i++)
WiredHome 12:109bf1558300 52 encoded_data[*output_length - 1 - i] = '=';
WiredHome 12:109bf1558300 53
WiredHome 12:109bf1558300 54 return encoded_data;
WiredHome 12:109bf1558300 55 }
WiredHome 12:109bf1558300 56
WiredHome 12:109bf1558300 57
WiredHome 12:109bf1558300 58 unsigned char * Base64::base64_decode(const char *data,size_t input_length,size_t *output_length)
WiredHome 12:109bf1558300 59 {
WiredHome 12:109bf1558300 60 if (decoding_table == NULL)
WiredHome 12:109bf1558300 61 build_decoding_table();
WiredHome 12:109bf1558300 62
WiredHome 12:109bf1558300 63 if (input_length % 4 != 0)
WiredHome 12:109bf1558300 64 return NULL;
WiredHome 12:109bf1558300 65
WiredHome 12:109bf1558300 66 *output_length = input_length / 4 * 3;
WiredHome 12:109bf1558300 67 if (data[input_length - 1] == '=') (*output_length)--;
WiredHome 12:109bf1558300 68 if (data[input_length - 2] == '=') (*output_length)--;
WiredHome 12:109bf1558300 69
WiredHome 12:109bf1558300 70 unsigned char *decoded_data = (unsigned char *)malloc(*output_length);
WiredHome 12:109bf1558300 71 if (decoded_data == NULL)
WiredHome 12:109bf1558300 72 return NULL;
WiredHome 12:109bf1558300 73
WiredHome 12:109bf1558300 74 for (int i = 0, j = 0; i < input_length;) {
WiredHome 12:109bf1558300 75
WiredHome 12:109bf1558300 76 uint32_t sextet_a = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
WiredHome 12:109bf1558300 77 uint32_t sextet_b = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
WiredHome 12:109bf1558300 78 uint32_t sextet_c = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
WiredHome 12:109bf1558300 79 uint32_t sextet_d = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]];
WiredHome 12:109bf1558300 80
WiredHome 12:109bf1558300 81 uint32_t triple = (sextet_a << 3 * 6)
WiredHome 12:109bf1558300 82 + (sextet_b << 2 * 6)
WiredHome 12:109bf1558300 83 + (sextet_c << 1 * 6)
WiredHome 12:109bf1558300 84 + (sextet_d << 0 * 6);
WiredHome 12:109bf1558300 85
WiredHome 12:109bf1558300 86 if (j < *output_length)
WiredHome 12:109bf1558300 87 decoded_data[j++] = (triple >> 2 * 8) & 0xFF;
WiredHome 12:109bf1558300 88 if (j < *output_length)
WiredHome 12:109bf1558300 89 decoded_data[j++] = (triple >> 1 * 8) & 0xFF;
WiredHome 12:109bf1558300 90 if (j < *output_length)
WiredHome 12:109bf1558300 91 decoded_data[j++] = (triple >> 0 * 8) & 0xFF;
WiredHome 12:109bf1558300 92 }
WiredHome 12:109bf1558300 93 return decoded_data;
WiredHome 12:109bf1558300 94 }
WiredHome 12:109bf1558300 95
WiredHome 12:109bf1558300 96
WiredHome 12:109bf1558300 97 void Base64::build_decoding_table()
WiredHome 12:109bf1558300 98 {
WiredHome 12:109bf1558300 99 decoding_table = (char *)malloc(256);
WiredHome 12:109bf1558300 100
WiredHome 12:109bf1558300 101 for (int i = 0; i < 64; i++)
WiredHome 12:109bf1558300 102 decoding_table[(unsigned char) encoding_table[i]] = i;
WiredHome 12:109bf1558300 103 }
WiredHome 12:109bf1558300 104