Added getPairs function

CMakeLists.txt

@@ -118,6 +118,7 @@ set(SOURCE_FILES
 	src/Timed.h
 	src/TimeRange.cpp src/TimeRange.h
 	src/Timeline.h
+	src/pairs.h
 	src/Exporter.cpp src/Exporter.h
 )
 add_executable(rhubarb ${SOURCE_FILES})
@@ -129,10 +130,12 @@ target_compile_options(rhubarb PUBLIC ${enableWarningsFlags})
 set(TEST_FILES
 	tests/stringToolsTests.cpp
 	tests/TimelineTests.cpp
+	tests/pairsTests.cpp
 	src/stringTools.cpp src/stringTools.h
 	src/Timeline.h
 	src/TimeRange.cpp src/TimeRange.h
 	src/centiseconds.cpp src/centiseconds.h
+	src/pairs.h
 )
 add_executable(runTests ${TEST_FILES})
 target_link_libraries(runTests gtest gmock gmock_main)

src/pairs.h

@@ -0,0 +1,20 @@
+#pragma once
+#include <vector>
+
+template<typename TCollection>
+std::vector<std::pair<typename TCollection::value_type, typename TCollection::value_type>> getPairs(const TCollection& collection) {
+	using TElement = typename TCollection::value_type;
+	using TPair = std::pair<TElement, TElement>;
+
+	auto begin = collection.begin();
+	auto end = collection.end();
+	if (begin == end || ++TCollection::const_iterator(begin) == end) {
+		return std::vector<TPair>();
+	}
+
+	std::vector<TPair> result;
+	for (auto first = begin, second = ++TCollection::const_iterator(begin); second != end; ++first, ++second) {
+		result.push_back(TPair(*first, *second));
+	}
+	return result;
+}

tests/pairsTests.cpp

@@ -0,0 +1,34 @@
+#include <gmock/gmock.h>
+#include "pairs.h"
+
+using namespace testing;
+using std::vector;
+using std::initializer_list;
+using std::pair;
+
+TEST(getPairs, emptyCollection) {
+	EXPECT_THAT(getPairs(vector<int>()), IsEmpty());
+}
+
+TEST(getPairs, oneElementCollection) {
+	EXPECT_THAT(getPairs(vector<int>{1}), IsEmpty());
+}
+
+TEST(getPairs, validCollection) {
+	{
+		auto actual = getPairs(vector<int>{ 1, 2 });
+		vector<pair<int, int>> expected{ {1, 2} };
+		EXPECT_THAT(actual, ElementsAreArray(expected));
+	}
+	{
+		auto actual = getPairs(vector<int>{ 1, 2, 3 });
+		vector<pair<int, int>> expected{ {1, 2}, {2, 3} };
+		EXPECT_THAT(actual, ElementsAreArray(expected));
+	}
+	{
+		auto actual = getPairs(vector<int>{ 1, 2, 3, 4 });
+		vector<pair<int, int>> expected{ {1, 2}, {2, 3}, {3, 4} };
+		EXPECT_THAT(actual, ElementsAreArray(expected));
+	}
+}
+