ceph/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/trace/propagation/detail/hex.h

   1 // Copyright The OpenTelemetry Authors
   2 // SPDX-License-Identifier: Apache-2.0
   3
   4 #pragma once
   5
   6 #include "opentelemetry/nostd/string_view.h"
   7
   8 #include <algorithm>
   9 #include <cstring>
  10
  11 OPENTELEMETRY_BEGIN_NAMESPACE
  12 namespace trace
  13 {
  14 namespace propagation
  15 {
  16 // NOTE - code within `detail` namespace implements internal details, and not part
  17 // of the public interface.
  18 namespace detail
  19 {
  20
  21 constexpr int8_t kHexDigits[256] = {
  22     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  23     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  24     0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1,
  25     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  26     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  27     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  28     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  29     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  30     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  31     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  32     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  33 };
  34
  35 inline int8_t HexToInt(char c)
  36 {
  37   return kHexDigits[uint8_t(c)];
  38 }
  39
  40 inline bool IsValidHex(nostd::string_view s)
  41 {
  42   return std::all_of(s.begin(), s.end(), [](char c) { return HexToInt(c) != -1; });
  43 }
  44
  45 /**
  46  * Converts a hexadecimal to binary format if the hex string will fit the buffer.
  47  * Smaller hex strings are left padded with zeroes.
  48  */
  49 inline bool HexToBinary(nostd::string_view hex, uint8_t *buffer, size_t buffer_size)
  50 {
  51   std::memset(buffer, 0, buffer_size);
  52
  53   if (hex.size() > buffer_size * 2)
  54   {
  55     return false;
  56   }
  57
  58   int64_t hex_size     = int64_t(hex.size());
  59   int64_t buffer_pos   = int64_t(buffer_size) - (hex_size + 1) / 2;
  60   int64_t last_hex_pos = hex_size - 1;
  61
  62   int64_t i = 0;
  63   for (; i < last_hex_pos; i += 2)
  64   {
  65     buffer[buffer_pos++] = (HexToInt(hex[i]) << 4) | HexToInt(hex[i + 1]);
  66   }
  67
  68   if (i == last_hex_pos)
  69   {
  70     buffer[buffer_pos] = HexToInt(hex[i]);
  71   }
  72
  73   return true;
  74 }
  75
  76 }  // namespace detail
  77 }  // namespace propagation
  78 }  // namespace trace
  79 OPENTELEMETRY_END_NAMESPACE