src/utility/wide_string.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2008-2017 by Andrzej Rybczak                            *
   3  *   electricityispower@gmail.com                                          *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.              *
  19  ***************************************************************************/
  20
  21 #include <cassert>
  22 #include "utility/wide_string.h"
  23
  24 size_t wideLength(const std::wstring &ws)
  25 {
  26         size_t result = 0;
  27         for (const auto &wc : ws)
  28         {
  29                 int len = wcwidth(wc);
  30                 if (len < 0)
  31                         ++result;
  32                 else
  33                         result += len;
  34         }
  35         return result;
  36 }
  37
  38 void wideCut(std::wstring &ws, size_t max_length)
  39 {
  40         size_t i = 0;
  41         int remained_len = max_length;
  42         for (; i < ws.length(); ++i)
  43         {
  44                 remained_len -= std::max(wcwidth(ws[i]), 1);
  45                 if (remained_len < 0)
  46                 {
  47                         ws.resize(i);
  48                         break;
  49                 }
  50         }
  51 }
  52
  53 std::wstring wideShorten(const std::wstring &ws, size_t max_length)
  54 {
  55         std::wstring result;
  56         if (wideLength(ws) > max_length)
  57         {
  58                 const size_t half_max = max_length/2 - 1;
  59                 size_t len = 0;
  60                 // get beginning of string
  61                 for (auto it = ws.begin(); it != ws.end(); ++it)
  62                 {
  63                         len += wcwidth(*it);
  64                         if (len > half_max)
  65                                 break;
  66                         result += *it;
  67                 }
  68                 len = 0;
  69                 std::wstring end;
  70                 // get end of string in reverse order
  71                 for (auto it = ws.rbegin(); it != ws.rend(); ++it)
  72                 {
  73                         len += wcwidth(*it);
  74                         if (len > half_max)
  75                                 break;
  76                         end += *it;
  77                 }
  78                 // apply end of string to its beginning
  79                 result += L"..";
  80                 result.append(end.rbegin(), end.rend());
  81         }
  82         else
  83                 result = ws;
  84         return result;
  85 }
  86