.. _program_listing_file_include_opentelemetry_trace_propagation_detail_hex.h:

Program Listing for File hex.h
==============================

|exhale_lsh| :ref:`Return to documentation for file <file_include_opentelemetry_trace_propagation_detail_hex.h>` (``include/opentelemetry/trace/propagation/detail/hex.h``)

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

.. code-block:: cpp

   #pragma once
   
   #include "opentelemetry/nostd/string_view.h"
   
   #include <algorithm>
   #include <cstring>
   
   OPENTELEMETRY_BEGIN_NAMESPACE
   namespace trace
   {
   namespace propagation
   {
   namespace detail
   {
   
   constexpr int8_t kHexDigits[256] = {
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
   };
   
   inline int8_t HexToInt(char c)
   {
     return kHexDigits[uint8_t(c)];
   }
   
   inline bool IsValidHex(nostd::string_view s)
   {
     return std::all_of(s.begin(), s.end(), [](char c) { return HexToInt(c) != -1; });
   }
   
   inline bool HexToBinary(nostd::string_view hex, uint8_t *buffer, size_t buffer_size)
   {
     std::memset(buffer, 0, buffer_size);
   
     if (hex.size() > buffer_size * 2)
     {
       return false;
     }
   
     int64_t hex_size     = int64_t(hex.size());
     int64_t buffer_pos   = int64_t(buffer_size) - (hex_size + 1) / 2;
     int64_t last_hex_pos = hex_size - 1;
   
     int64_t i = 0;
     for (; i < last_hex_pos; i += 2)
     {
       buffer[buffer_pos++] = (HexToInt(hex[i]) << 4) | HexToInt(hex[i + 1]);
     }
   
     if (i == last_hex_pos)
     {
       buffer[buffer_pos] = HexToInt(hex[i]);
     }
   
     return true;
   }
   
   }  // namespace detail
   }  // namespace propagation
   }  // namespace trace
   OPENTELEMETRY_END_NAMESPACE