src/lib/image_filename_sorter.cc

   1 /*
   2     Copyright (C) 2015-2016 Carl Hetherington <cth@carlh.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include "raw_convert.h"
  21 #include <boost/filesystem.hpp>
  22 #include <boost/foreach.hpp>
  23 #include <iostream>
  24
  25 class ImageFilenameSorter
  26 {
  27 public:
  28         bool operator() (boost::filesystem::path a, boost::filesystem::path b)
  29         {
  30                 std::list<int> na = extract_numbers (a);
  31                 std::list<int> nb = extract_numbers (b);
  32                 if (na.empty() || nb.empty()) {
  33                         return a.string() < b.string();
  34                 }
  35
  36                 if (na.size() != nb.size()) {
  37                         /* Just use the first one */
  38                         return na.front() < nb.front();
  39                 }
  40
  41                 std::list<int>::const_iterator i = na.begin ();
  42                 std::list<int>::const_iterator j = nb.begin ();
  43
  44                 while (i != na.end()) {
  45                         if (*i != *j) {
  46                                 return *i < *j;
  47                         }
  48                         ++i;
  49                         ++j;
  50                 }
  51
  52                 /* All the same */
  53                 return false;
  54         }
  55
  56 private:
  57         std::list<int> extract_numbers (boost::filesystem::path p)
  58         {
  59                 p = p.leaf ();
  60
  61                 std::list<std::string> numbers;
  62
  63                 std::string current;
  64                 for (size_t i = 0; i < p.string().size(); ++i) {
  65                         if (isdigit (p.string()[i])) {
  66                                 current += p.string()[i];
  67                         } else {
  68                                 if (!current.empty ()) {
  69                                         numbers.push_back (current);
  70                                         current.clear ();
  71                                 }
  72                         }
  73                 }
  74
  75                 if (!current.empty ()) {
  76                         numbers.push_back (current);
  77                 }
  78
  79                 std::list<int> numbers_as_int;
  80                 BOOST_FOREACH (std::string i, numbers) {
  81                         numbers_as_int.push_back (raw_convert<int> (i));
  82                 }
  83
  84                 return numbers_as_int;
  85         }
  86 };