src/utils.c

   1 /** \ingroup contrac
   2  * @file
   3  * @author      David Llewellyn-Jones
   4  * @version     $(VERSION)
   5  *
   6  * @section LICENSE
   7  *
   8  *
   9  *
  10  * @brief
  11  * @section DESCRIPTION
  12  *
  13  *
  14  *
  15  */
  16
  17 // Includes
  18
  19 #include <openssl/evp.h>
  20
  21 // Defines
  22
  23 // Structures
  24
  25 // Function prototypes
  26
  27 // Function definitions
  28
  29 // Function definitions
  30
  31 size_t base64_encode_size(size_t binary_input) {
  32         return (((size_t)((binary_input + 2) / 3)) * 4) + 1;
  33 }
  34
  35 size_t base64_decode_size(size_t base64_input) {
  36         return (((size_t)((base64_input + 3) / 4)) * 3) + 1;
  37 }
  38
  39 void base64_encode_binary_to_base64(unsigned char const *input, size_t input_size, unsigned char *output, size_t *output_size) {
  40         size_t size_in;
  41         size_t size_out;
  42
  43         size_in = input_size;
  44         size_out = base64_encode_size(input_size);
  45
  46         if (size_out > *output_size) {
  47                 size_in = base64_decode_size(*output_size - 1) - 1;
  48         }
  49         *output_size = base64_encode_size(size_in);
  50
  51         EVP_EncodeBlock(output, input, size_in);
  52 }
  53
  54 void base64_decode_base64_to_binary(unsigned char const *input, size_t input_size, unsigned char *output, size_t *output_size) {
  55         size_t size_in;
  56         size_t size_out;
  57
  58         size_in = input_size;
  59         size_out = base64_decode_size(input_size);
  60
  61         if (size_out > *output_size) {
  62                 size_in = base64_encode_size(*output_size - 1) - 1;
  63         }
  64         *output_size = base64_decode_size(size_in);
  65
  66         EVP_DecodeBlock(output, input, size_in);
  67 }
  68
  69 uint32_t epoch_to_day_number(time_t epoch) {
  70         uint32_t day_number;
  71
  72         // DayNumber <- (Number of Seconds since Epoch) / (60 * 60 * 24)
  73         day_number = epoch / (60 * 60 * 24);
  74
  75         return day_number;
  76 }
  77
  78 uint8_t epoch_to_time_interval_number(time_t epoch) {
  79         uint8_t time_interval_number;
  80         uint32_t day_number;
  81         uint32_t seconds;
  82
  83         // TimeNumberInterval <- (Seconds Since Start of DayNumber) / (60 * 10)
  84         day_number = epoch_to_day_number(epoch);
  85         seconds = epoch - (day_number * (60 * 60 * 24));
  86
  87         time_interval_number = seconds / (60 * 10);
  88
  89         // Falls in interval [0,143]
  90         if (time_interval_number > 143) {
  91                 time_interval_number = 143;
  92         }
  93
  94         return time_interval_number;
  95 }
  96
  97