src/lib/image_filename_sorter.cc

   1 /*
   2     Copyright (C) 2015 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 <iostream>
  21 #include <boost/filesystem.hpp>
  22 #include <boost/optional.hpp>
  23 #include <boost/foreach.hpp>
  24 #include "raw_convert.h"
  25
  26 class ImageFilenameSorter
  27 {
  28 public:
  29         bool operator() (boost::filesystem::path a, boost::filesystem::path b)
  30         {
  31                 std::list<int> na = extract_numbers (a);
  32                 std::list<int> nb = extract_numbers (b);
  33                 if (na.empty() || nb.empty()) {
  34                         return a.string() < b.string();
  35                 }
  36
  37                 if (na.size() != nb.size()) {
  38                         /* Just use the first one */
  39                         return na.front() < nb.front();
  40                 }
  41
  42                 std::list<int>::const_iterator i = na.begin ();
  43                 std::list<int>::const_iterator j = nb.begin ();
  44
  45                 while (i != na.end()) {
  46                         if (*i != *j) {
  47                                 return *i < *j;
  48                         }
  49                         ++i;
  50                         ++j;
  51                 }
  52
  53                 /* All the same */
  54                 return false;
  55         }
  56
  57 private:
  58         std::list<int> extract_numbers (boost::filesystem::path p)
  59         {
  60                 p = p.leaf ();
  61
  62                 std::list<std::string> numbers;
  63
  64                 std::string current;
  65                 for (size_t i = 0; i < p.string().size(); ++i) {
  66                         if (isdigit (p.string()[i])) {
  67                                 current += p.string()[i];
  68                         } else {
  69                                 if (!current.empty ()) {
  70                                         numbers.push_back (current);
  71                                         current.clear ();
  72                                 }
  73                         }
  74                 }
  75
  76                 if (!current.empty ()) {
  77                         numbers.push_back (current);
  78                 }
  79
  80                 std::list<int> numbers_as_int;
  81                 BOOST_FOREACH (std::string i, numbers) {
  82                         numbers_as_int.push_back (raw_convert<int> (i));
  83                 }
  84
  85                 return numbers_as_int;
  86         }
  87 };