Added operator- member implementation and improved test cases

* operator- takes a reference to a const std::string::const_iterator and as such enables determining the actual position of a codepoint within a string
* ranged for loops in test cases now take the iterator value by rvalue reference instead of by value

3 files changed, 10 insertions, 3 deletions

diff --git a/src/codepoint_iterator.cc b/src/codepoint_iterator.cc
index b2f6d81..59cb23b 100644
--- a/src/codepoint_iterator.cc
+++ b/src/codepoint_iterator.cc
@@ -34,6 +34,11 @@ bool CodepointIterator::operator!=(
 	return this->iterator_ != src;
 }
 
+std::ptrdiff_t CodepointIterator::operator-(
+	const std::string::const_iterator& src) const {
+	return this->iterator_ - src;
+}
+
 char32_t CodepointIterator::operator*() {
 	std::uint8_t  currByte  = *(this->iterator_);
 	char32_t codePoint      = 0;
diff --git a/src/codepoint_iterator.h b/src/codepoint_iterator.h
index b505587..d1806e5 100644
--- a/src/codepoint_iterator.h
+++ b/src/codepoint_iterator.h
@@ -22,6 +22,8 @@ class CodepointIterator : public std::iterator<std::bidirectional_iterator_tag,
 		bool operator!=(const CodepointIterator&) const;
 		bool operator!=(const std::string::const_iterator&) const;
 
+		std::ptrdiff_t operator-(const std::string::const_iterator&) const;
+
 		char32_t operator*();
 
 		CodepointIterator& operator++();
diff --git a/test.cc b/test.cc
index 0693970..f0feb74 100644
--- a/test.cc
+++ b/test.cc
@@ -43,7 +43,7 @@ class CodepointIteratorTest : public ::testing::Test {
 };
 
 TEST_F(CodepointIteratorTest, ForwardIteration) {
-	for ( auto tmp : this->sample_ ) {
+	for ( auto&& tmp : this->sample_ ) {
 		size_t length = 0;
 
 		for ( UTF8::CodepointIterator iter(tmp.text.cbegin());
@@ -57,7 +57,7 @@ TEST_F(CodepointIteratorTest, ForwardIteration) {
 }
 
 TEST_F(CodepointIteratorTest, ReverseIteration) {
-	for ( auto tmp : this->sample_ ) {
+	for ( auto&& tmp : this->sample_ ) {
 		size_t length = 0;
 
 		for ( UTF8::CodepointIterator iter(tmp.text.cend());
@@ -71,7 +71,7 @@ TEST_F(CodepointIteratorTest, ReverseIteration) {
 }
 
 TEST_F(CodepointIteratorTest, Dereferencing) {
-	for ( auto tmp : this->sample_ ) {
+	for ( auto&& tmp : this->sample_ ) {
 		size_t index = 0;
 
 		for ( UTF8::CodepointIterator iter(tmp.text.cbegin());