#40 Add basic_string + basic_string_view concatenation

rick-de-water · Jan 6, 2020 · 85f9406 · 85f9406
1 parent ab81b81
commit 85f9406
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Showing 2 changed files with 107 additions and 29 deletions.
diff --git a/src/lib/lingo/string.hpp b/src/lib/lingo/string.hpp
@@ -341,43 +341,35 @@ namespace lingo
 			}
 
 			// Allocate memory
-			const size_type current_size = size();
-			const size_type new_size = current_size + result.size;
-			_storage.grow(new_size);
-
-			// Destruct old null terminator
-			_storage.destruct(_storage.data() + current_size, 1);
+			_storage.grow(size() + result.size);
 
-			// Fill memory
-			_storage.copy_construct(_storage.data() + current_size, encoded_point, result.size);
-
-			// Construct new null terminator
-			_storage.copy_construct(_storage.data() + new_size, &null_terminator, 1);
-
-			// Update size
-			_storage.set_size(new_size);
+			// Append data
+			append(string_view(encoded_point, result.size));
 		}
 
 		template <typename OtherAllocator>
-		basic_string& operator += (const basic_string<Encoding, Page, OtherAllocator> & other)
+		basic_string& operator += (const basic_string<Encoding, Page, OtherAllocator>& other)
 		{
+			// We can't simply call the string_view version here
+			// If &other == this, the data pointer in the string view might become invalid when growing the capacity
+
 			// Allocate memory
-			const size_type current_size = size();
-			const size_type added_size = other.size();
-			const size_type new_size = current_size + added_size;
-			_storage.grow(new_size);
+			_storage.grow(size() + other.size());
 
-			// Destruct old null terminator
-			_storage.destruct(_storage.data() + current_size, 1);
+			// Append data
+			append(other);
 
-			// Fill memory
-			_storage.copy_construct(_storage.data() + current_size, other.data(), added_size);
+			// Return this
+			return *this;
+		}
 
-			// Construct new null terminator
-			_storage.copy_construct(_storage.data() + new_size, &null_terminator, 1);
+		basic_string& operator += (string_view other)
+		{
+			// Allocate memory
+			_storage.grow(size() + other.size());
 
-			// Update size
-			_storage.set_size(new_size);
+			// Append data
+			append(other);
 
 			// Return this
 			return *this;
@@ -423,6 +415,27 @@ namespace lingo
 		}
 
 		private:
+		void append(string_view other)
+		{
+			const size_type current_size = size();
+			const size_type added_size = other.size();
+			const size_type new_size = current_size + added_size;
+
+			assert(new_size <= capacity());
+
+			// Destruct old null terminator
+			_storage.destruct(_storage.data() + current_size, 1);
+
+			// Fill memory
+			_storage.copy_construct(_storage.data() + current_size, other.data(), added_size);
+
+			// Construct new null terminator
+			_storage.copy_construct(_storage.data() + new_size, &null_terminator, 1);
+
+			// Update size
+			_storage.set_size(new_size);
+		}
+
 		storage_type _storage;
 	};
 
@@ -434,7 +447,31 @@ namespace lingo
 	template <typename Encoding, typename Page, typename LeftAllocator, typename RightAllocator, typename ResultAllocator = LeftAllocator>
 	basic_string<Encoding, Page, ResultAllocator> operator + (basic_string<Encoding, Page, LeftAllocator> left, basic_string<Encoding, Page, RightAllocator> right)
 	{
-		basic_string<Encoding, Page, ResultAllocator> result;
+		return operator+<Encoding, Page, ResultAllocator>(
+			left.operator lingo::basic_string_view<Encoding, Page>(),
+			right.operator lingo::basic_string_view<Encoding, Page>());
+	}
+
+	template <typename Encoding, typename Page, typename LeftAllocator, typename ResultAllocator = LeftAllocator>
+	basic_string<Encoding, Page, ResultAllocator> operator + (basic_string<Encoding, Page, LeftAllocator> left, basic_string_view<Encoding, Page> right)
+	{
+		return operator+<Encoding, Page, ResultAllocator>(
+			left.operator lingo::basic_string_view<Encoding, Page>(),
+			right);
+	}
+
+	template <typename Encoding, typename Page, typename RightAllocator, typename ResultAllocator = RightAllocator>
+	basic_string<Encoding, Page, ResultAllocator> operator + (basic_string_view<Encoding, Page> left, basic_string<Encoding, Page, RightAllocator> right)
+	{
+		return operator+<Encoding, Page, ResultAllocator>(
+			left,
+			right.operator lingo::basic_string_view<Encoding, Page>());
+	}
+
+	template <typename Encoding, typename Page, typename Allocator = internal::default_allocator<Encoding>>
+	basic_string<Encoding, Page, Allocator> operator + (basic_string_view<Encoding, Page> left, basic_string_view<Encoding, Page> right)
+	{
+		basic_string<Encoding, Page, Allocator> result;
 		result.reserve(left.size() + right.size());
 		result += left;
 		result += right;

diff --git a/tests/lingo/string.cpp b/tests/lingo/string.cpp
@@ -541,7 +541,7 @@ LINGO_UNIT_TEST_CASE("A string can be concatenated to another string")
 
 	REQUIRE_FALSE(std::is_same<string_type, different_allocator_string_type>::value);
 
-	string_view_type source_string = lingo::test::test_string<unit_type>::value;
+	const string_view_type source_string = lingo::test::test_string<unit_type>::value;
 	string_type test_string = source_string;
 	different_allocator_string_type different_allocator_test_string = lingo::test::test_string<unit_type>::value;
 
@@ -610,4 +610,45 @@ LINGO_UNIT_TEST_CASE("A string can be concatenated to another string")
 		REQUIRE(string_view_type(different_allocator_test_string.data(), source_string.size()) == source_string);
 		REQUIRE(string_view_type(different_allocator_test_string.data() + source_string.size(), source_string.size()) == source_string);
 	}
+}
+
+LINGO_UNIT_TEST_CASE("A string_view can be concatenated to a string")
+{
+	LINGO_UNIT_TEST_TYPEDEFS;
+
+	const string_view_type source_string = lingo::test::test_string<unit_type>::value;
+	string_type test_string;
+
+	test_string = test_string + source_string;
+	REQUIRE(test_string == source_string);
+
+	for (size_type i = 0; i < 10; ++i)
+	{
+		test_string += source_string;
+		REQUIRE(test_string.size() == source_string.size() * (i + 2));
+
+		for (size_type j = 0; j < i + 2; ++j)
+		{
+			REQUIRE(string_view_type(test_string.data() + source_string.size() * j, source_string.size()) == source_string);
+		}
+	}
+}
+
+LINGO_UNIT_TEST_CASE("A string_view can be concatenated to a string_view")
+{
+	LINGO_UNIT_TEST_TYPEDEFS;
+
+	const string_view_type source_string = lingo::test::test_string<unit_type>::value;
+	string_type test_string;
+
+	test_string = source_string + source_string;
+	REQUIRE(test_string.size() == source_string.size() * 2);
+	REQUIRE(string_view_type(test_string.data(), source_string.size()) == source_string);
+	REQUIRE(string_view_type(test_string.data() + source_string.size(), source_string.size()) == source_string);
+
+	for (size_type i = 0; i < 10; ++i)
+	{
+		test_string += source_string;
+		REQUIRE(test_string.size() == source_string.size() * (i + 3));
+	}
 }