From 12e20e180062dbc338e775bd1f5ec7a2af91df7f Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Fri, 17 Jul 2015 00:41:04 +0100
Subject: [PATCH] Improve image filename sorter.

---
 ChangeLog                          |  4 +++
 src/lib/image_filename_sorter.cc   | 40 ++++++++++++++++++++----------
 test/image_filename_sorter_test.cc |  2 ++
 3 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3d149a824..d6ae72fb8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2015-07-17  Carl Hetherington  <cth@carlh.net>
+
+	* Improve still-image filename sorting.
+
 2015-07-16  Carl Hetherington  <cth@carlh.net>
 
 	* Updated ru_RU translation from Igor Voytovich.
diff --git a/src/lib/image_filename_sorter.cc b/src/lib/image_filename_sorter.cc
index 5a3e1dcec..037446398 100644
--- a/src/lib/image_filename_sorter.cc
+++ b/src/lib/image_filename_sorter.cc
@@ -27,35 +27,49 @@ class ImageFilenameSorter
 public:
 	bool operator() (boost::filesystem::path a, boost::filesystem::path b)
 	{
-		boost::optional<int> na = extract_number (a);
-		boost::optional<int> nb = extract_number (b);
-		if (!na || !nb) {
-			return a.string() < b.string();
+		std::vector<int> na = extract_numbers (a);
+		std::vector<int> nb = extract_numbers (b);
+
+		std::vector<int>::const_iterator i = na.begin ();
+		std::vector<int>::const_iterator j = nb.begin ();
+
+		while (true) {
+			if (i == na.end () || j == nb.end ()) {
+				return false;
+			}
+
+			if (*i != *j) {
+				return *i < *j;
+			}
+
+			++i;
+			++j;
 		}
 
-		return na.get() < nb.get();
+		/* NOT REACHED */
+		return false;
 	}
 
 private:
-	boost::optional<int> extract_number (boost::filesystem::path p)
+	std::vector<int> extract_numbers (boost::filesystem::path p)
 	{
 		p = p.leaf ();
 
+		std::vector<int> numbers;
 		std::string number;
 		for (size_t i = 0; i < p.string().size(); ++i) {
 			if (isdigit (p.string()[i])) {
 				number += p.string()[i];
-			} else {
-				if (!number.empty ()) {
-					break;
-				}
+			} else if (!number.empty ()) {
+				numbers.push_back (raw_convert<int> (number));
+				number.clear ();
 			}
 		}
 
-		if (number.empty ()) {
-			return boost::optional<int> ();
+		if (!number.empty ()) {
+			numbers.push_back (raw_convert<int> (number));
 		}
 
-		return raw_convert<int> (number);
+		return numbers;
 	}
 };
diff --git a/test/image_filename_sorter_test.cc b/test/image_filename_sorter_test.cc
index 830065f77..4bdd16f55 100644
--- a/test/image_filename_sorter_test.cc
+++ b/test/image_filename_sorter_test.cc
@@ -31,6 +31,7 @@ BOOST_AUTO_TEST_CASE (image_filename_sorter_test)
 	BOOST_CHECK (x ("1", "999"));
 	BOOST_CHECK (x ("00057.tif", "00166.tif"));
 	BOOST_CHECK (x ("/my/numeric999/path/00057.tif", "/my/numeric999/path/00166.tif"));
+	BOOST_CHECK (x ("1_01.tif", "1_02.tif"));
 
 	BOOST_CHECK (!x ("abc0000000002", "abc0000000001"));
 	BOOST_CHECK (!x ("2", "1"));
@@ -38,4 +39,5 @@ BOOST_AUTO_TEST_CASE (image_filename_sorter_test)
 	BOOST_CHECK (!x ("2", "0001"));
 	BOOST_CHECK (!x ("999", "1"));
 	BOOST_CHECK (!x ("/my/numeric999/path/00166.tif", "/my/numeric999/path/00057.tif"));
+	BOOST_CHECK (!x ("1_02.tif", "1_01.tif"));
 }
-- 
2.30.2