ceph/src/common/pretty_binary.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #include "pretty_binary.h"
   5 #include <stdexcept>
   6 #include <sstream>
   7
   8 std::string pretty_binary_string_reverse(const std::string& pretty)
   9 {
  10   size_t i = 0;
  11   auto raise = [&](size_t failpos) {
  12     std::ostringstream ss;
  13     ss << "invalid char at pos " << failpos << " of " << pretty;
  14     throw std::invalid_argument(ss.str());
  15   };
  16   auto hexdigit = [&](unsigned char c) -> int32_t {
  17     if (c >= '0' && c <= '9') return c - '0';
  18     if (c >= 'a' && c <= 'f') return c - 'a' + 10;
  19     if (c >= 'A' && c <= 'F') return c - 'A' + 10;
  20     return -1;
  21   };
  22   auto require = [&](unsigned char c) {
  23     if (i >= pretty.length() || pretty[i] != c) {
  24       raise(i);
  25     }
  26     ++i;
  27   };
  28   std::string bin;
  29   if (pretty.empty())
  30     return bin;
  31   bin.reserve(pretty.length());
  32   bool strmode;
  33   switch (pretty[0]) {
  34     case '\'':
  35       ++i;
  36       strmode = true;
  37       break;
  38     case '0':
  39       ++i;
  40       require('x');
  41       if (i == pretty.length()) {
  42         raise(i);
  43       }
  44       strmode = false;
  45       break;
  46     default:
  47       raise(0);
  48   }
  49   for (; i < pretty.length();) {
  50     if (strmode) {
  51       if (pretty[i] == '\'') {
  52         if (i + 1 < pretty.length() && pretty[i + 1] == '\'') {
  53           bin.push_back('\'');
  54           i += 2;
  55         } else {
  56           ++i;
  57           strmode = false;
  58           if (i + 1 < pretty.length()) {
  59             require('0');
  60             require('x');
  61             if (i == pretty.length()) {
  62               raise(i);
  63             }
  64           }
  65         }
  66       } else {
  67         bin.push_back(pretty[i]);
  68         ++i;
  69       }
  70     } else {
  71       if (pretty[i] != '\'') {
  72         int32_t hex0 = hexdigit(pretty[i]);
  73         if (hex0 < 0) {
  74           raise(i);
  75         }
  76         ++i;
  77         if (i >= pretty.length()) {
  78           raise(i);
  79         }
  80         int32_t hex1 = hexdigit(pretty[i]);
  81         if (hex1 < 0) {
  82           raise(i);
  83         }
  84         bin.push_back(hex0 * 0x10 + hex1);
  85         ++i;
  86       } else {
  87         strmode = true;
  88         ++i;
  89       }
  90     }
  91   }
  92   if (strmode)
  93     raise(i);
  94   return bin;
  95 }