ceph/src/common/pretty_binary.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #pragma once
   5
   6 #include <string>
   7
   8 template<typename S>
   9 static std::string pretty_binary_string(const S& bin)
  10 {
  11   std::string pretty;
  12   if (bin.empty())
  13     return pretty;
  14   pretty.reserve(bin.length() * 3);
  15   auto printable = [](unsigned char c) -> bool {
  16     return (c >= 32) && (c <= 126);
  17   };
  18   auto append_hex = [&](unsigned char c) {
  19     static const char hex[16] = {'0', '1', '2', '3',
  20                                  '4', '5', '6', '7',
  21                                  '8', '9', 'A', 'B',
  22                                  'C', 'D', 'E', 'F'};
  23     pretty.push_back(hex[c / 16]);
  24     pretty.push_back(hex[c % 16]);
  25   };
  26   // prologue
  27   bool strmode = printable(bin[0]);
  28   if (strmode) {
  29     pretty.push_back('\'');
  30   } else {
  31     pretty.push_back('0');
  32     pretty.push_back('x');
  33   }
  34   for (size_t i = 0; i < bin.length(); ++i) {
  35     // change mode from hex to str if following 3 characters are printable
  36     if (strmode) {
  37       if (!printable(bin[i])) {
  38         pretty.push_back('\'');
  39         pretty.push_back('0');
  40         pretty.push_back('x');
  41         strmode = false;
  42       }
  43     } else {
  44       if (i + 2 < bin.length() &&
  45           printable(bin[i]) &&
  46           printable(bin[i + 1]) &&
  47           printable(bin[i + 2])) {
  48         pretty.push_back('\'');
  49         strmode = true;
  50       }
  51     }
  52     if (strmode) {
  53       if (bin[i] == '\'')
  54         pretty.push_back('\'');
  55       pretty.push_back(bin[i]);
  56     } else {
  57       append_hex(bin[i]);
  58     }
  59   }
  60   // epilog
  61   if (strmode) {
  62     pretty.push_back('\'');
  63   }
  64   return pretty;
  65 }
  66
  67 std::string pretty_binary_string_reverse(const std::string& pretty);