Add C4NullableBasicStringView for std::string_view construction where…

… nullptr may be passed (fixes #111)
legacyclonk · Sep 24, 2023 · f3c8a68 · f3c8a68
1 parent 60c64cd
commit f3c8a68
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Showing 3 changed files with 47 additions and 5 deletions.
diff --git a/src/C4GuiEdit.cpp b/src/C4GuiEdit.cpp
@@ -157,12 +157,15 @@ void Edit::DeleteSelection()
 	OnTextChange();
 }
 
-bool Edit::InsertText(std::string_view text, bool fUser)
+bool Edit::InsertText(const C4NullableStringView text, bool fUser)
 {
 	// empty previous selection
 	if (iSelectionStart != iSelectionEnd) DeleteSelection();
+
+	const std::string_view view{text};
+
 	// check buffer length
-	auto iTextLen = text.size();
+	auto iTextLen = view.size();
 	const auto iTextEnd = SLen(Text);
 	bool fBufferOK = (iTextLen + iTextEnd <= (iMaxTextLength - 1));
 	if (!fBufferOK) iTextLen -= iTextEnd + iTextLen - (iMaxTextLength - 1);
@@ -173,7 +176,7 @@ bool Edit::InsertText(std::string_view text, bool fUser)
 	int32_t i;
 	for (i = iTextEnd; i >= iCursorPos; --i) Text[i + iTextLen] = Text[i];
 	// insert buffer into text
-	for (i = iTextLen; i; --i) Text[iCursorPos + i - 1] = text[i - 1];
+	for (i = iTextLen; i; --i) Text[iCursorPos + i - 1] = view[i - 1];
 	if (fUser)
 	{
 		// advance cursor

diff --git a/src/C4GuiEdit.h b/src/C4GuiEdit.h
@@ -56,10 +56,10 @@ class Edit : public Control
 	void Deselect(); // clear selection range
 
 public:
-	bool InsertText(std::string_view text, bool fUser); // insert text at cursor pos (returns whether all text could be inserted)
+	bool InsertText(C4NullableStringView text, bool fUser); // insert text at cursor pos (returns whether all text could be inserted)
 	void ClearText(); // remove all the text
 	void DeleteSelection(); // deletes the selected text. Adjust cursor position if necessary
-	bool SetText(std::string_view text, bool fUser) { ClearText(); return InsertText(text, fUser); }
+	bool SetText(const C4NullableStringView text, bool fUser) { ClearText(); return InsertText(text, fUser); }
 	void SetPasswordMask(char cNewPasswordMask) { cPasswordMask = cNewPasswordMask; } // mask edit box contents using the given character
 
 private:

diff --git a/src/C4Strings.h b/src/C4Strings.h
@@ -121,3 +121,42 @@ inline int ssprintf(char (&str)[N], const char *fmt, Args... args)
 	if (m >= N) { m = N - 1; str[m] = 0; }
 	return m;
 }
+
+template<typename Char, typename Traits = std::char_traits<Char>>
+struct C4NullableBasicStringView
+{
+	std::basic_string_view<Char, Traits> View;
+
+	constexpr C4NullableBasicStringView(auto &&...args)
+		: View{std::forward<decltype(args)>(args)...} {}
+
+	constexpr C4NullableBasicStringView(const Char *const ptr)
+	{
+		if (ptr)
+		{
+			View = ptr;
+		}
+		else
+		{
+			View = {};
+		}
+	}
+
+	constexpr C4NullableBasicStringView(const C4NullableBasicStringView &other) noexcept
+	{
+		View = other.View;
+	}
+
+	constexpr C4NullableBasicStringView &operator=(const C4NullableBasicStringView &other) noexcept
+	{
+		View = other.View;
+		return *this;
+	}
+
+	constexpr operator std::basic_string_view<Char, Traits>() const noexcept
+	{
+		return View;
+	}
+};
+
+using C4NullableStringView = C4NullableBasicStringView<char>;