.. _program_listing_file_components_Util_src_Hex.cpp:

Program Listing for File Hex.cpp
================================

|exhale_lsh| :ref:`Return to documentation for file <file_components_Util_src_Hex.cpp>` (``components/Util/src/Hex.cpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   
   #include "Hex.h"
   
   namespace util {
   
   esp_err_t hexToInt(const char c, int& r)
   {
       if (c >= '0' && c <= '9') {
           r = c - '0';
           return ESP_OK;
       }
       if (c >= 'A' && c <= 'F') {
           r = c - 'A' + 10;
           return ESP_OK;
       }
       if (c >= 'a' && c <= 'f') {
           r = c - 'a' + 10;
           return ESP_OK;
       }
   
       return ESP_FAIL;
   }
   
   esp_err_t hexToBytes(const char* src, std::uint8_t* target)
   {
       esp_err_t err;
   
       while (src[0] != '\0' && src[1] != '\0') {
           int digit0 = 0;
           int digit1 = 0;
           err = hexToInt(src[0], digit0);
           if (err != ESP_OK) return err;
   
           err = hexToInt(src[1], digit1);
           if (err != ESP_OK) return err;
   
           target[0] = static_cast<std::uint8_t>((digit0 * 16) + digit1);
           target += 1;
           src += 2;
       }
   
       return ESP_OK;
   }
   
   
   esp_err_t bytesToHex(std::uint8_t* buf, char* dst, std::size_t len)
   {
       static const char hexmap[] = {
           '0', '1', '2', '3', '4', '5',
           '6', '7', '8', '9', 'a', 'b',
           'c', 'd', 'e', 'f'};
   
       for (size_t i = 0; i < len; i++) {
           const uint8_t upper = (buf[i] & 0xf0) >> 4;
           const uint8_t lower = (buf[i] & 0x0f);
           dst[i * 2] = hexmap[upper];
           dst[i * 2 + 1] = hexmap[lower];
       }
   
       dst[len * 2] = '\0';
   
       return ESP_OK;
   }
   
   } // namespace util