Add clipboard

Signed-off-by: Slendi <slendi@socopon.com>

src/ImGui.cpp

@@ -19,67 +19,52 @@ struct CodepointSpan {
 	usize end {};
 };
 
-auto decode_utf8(std::string_view text) -> std::vector<CodepointSpan>
+constexpr auto utf8_rune_from_first(char const *s) -> u32
+{
+	u8 b0 = static_cast<u8>(s[0]);
+	if (b0 < 0x80)
+		return b0;
+
+	if ((b0 & 0xE0) == 0xC0)
+		return ((b0 & 0x1F) << 6) | (static_cast<u8>(s[1]) & 0x3F);
+
+	if ((b0 & 0xF0) == 0xE0)
+		return ((b0 & 0x0F) << 12) | ((static_cast<u8>(s[1]) & 0x3F) << 6)
+		    | (static_cast<u8>(s[2]) & 0x3F);
+
+	if ((b0 & 0xF8) == 0xF0)
+		return ((b0 & 0x07) << 18) | ((static_cast<u8>(s[1]) & 0x3F) << 12)
+		    | ((static_cast<u8>(s[2]) & 0x3F) << 6)
+		    | (static_cast<u8>(s[3]) & 0x3F);
+
+	return 0xFFFD;
+}
+
+constexpr auto decode_utf8(std::string_view text) -> std::vector<CodepointSpan>
 {
 	std::vector<CodepointSpan> spans;
 	usize i = 0;
 	spans.reserve(text.size());
 
 	while (i < text.size()) {
-		u8 const byte = static_cast<u8>(text[i]);
-		usize const start = i;
-		usize length = 1;
-		u32 cp = 0xFFFD;
+		u8 b = static_cast<u8>(text[i]);
+		usize len = 1;
 
-		if (byte < 0x80) {
-			cp = byte;
-		} else if ((byte & 0xE0) == 0xC0) {
-			if (i + 1 < text.size()) {
-				u8 const b1 = static_cast<u8>(text[i + 1]);
-				if ((b1 & 0xC0) == 0x80) {
-					u32 const t = ((static_cast<u32>(byte) & 0x1F) << 6)
-					    | (static_cast<u32>(b1) & 0x3F);
-					if (t >= 0x80) {
-						cp = t;
-						length = 2;
-					}
-				}
-			}
-		} else if ((byte & 0xF0) == 0xE0) {
-			if (i + 2 < text.size()) {
-				u8 const b1 = static_cast<u8>(text[i + 1]);
-				u8 const b2 = static_cast<u8>(text[i + 2]);
-				if ((b1 & 0xC0) == 0x80 && (b2 & 0xC0) == 0x80) {
-					u32 const t = ((static_cast<u32>(byte) & 0x0F) << 12)
-					    | ((static_cast<u32>(b1) & 0x3F) << 6)
-					    | (static_cast<u32>(b2) & 0x3F);
-					if (t >= 0x800 && (t < 0xD800 || t > 0xDFFF)) {
-						cp = t;
-						length = 3;
-					}
-				}
-			}
-		} else if ((byte & 0xF8) == 0xF0) {
-			if (i + 3 < text.size()) {
-				u8 const b1 = static_cast<u8>(text[i + 1]);
-				u8 const b2 = static_cast<u8>(text[i + 2]);
-				u8 const b3 = static_cast<u8>(text[i + 3]);
-				if ((b1 & 0xC0) == 0x80 && (b2 & 0xC0) == 0x80
-				    && (b3 & 0xC0) == 0x80) {
-					u32 const t = ((static_cast<u32>(byte) & 0x07) << 18)
-					    | ((static_cast<u32>(b1) & 0x3F) << 12)
-					    | ((static_cast<u32>(b2) & 0x3F) << 6)
-					    | (static_cast<u32>(b3) & 0x3F);
-					if (t >= 0x10000 && t <= 0x10FFFF) {
-						cp = t;
-						length = 4;
-					}
-				}
-			}
-		}
+		if (b < 0x80)
+			len = 1;
+		else if ((b & 0xE0) == 0xC0)
+			len = 2;
+		else if ((b & 0xF0) == 0xE0)
+			len = 3;
+		else if ((b & 0xF8) == 0xF0)
+			len = 4;
 
-		spans.push_back(CodepointSpan { cp, start, start + length });
-		i += length;
+		if (i + len > text.size())
+			len = 1; // avoid overflow
+
+		u32 cp = utf8_rune_from_first(text.data() + i);
+		spans.push_back({ cp, i, i + len });
+		i += len;
 	}
 
 	return spans;
@@ -158,14 +143,25 @@ ImGui::ImGui(std::shared_ptr<TextRenderer> text_renderer)
 {
 }
 
-void ImGui::begin(u32 const rune, bool ctrl, bool shift)
+void ImGui::begin(u32 const rune, bool ctrl, bool shift,
+    std::string_view const clipboard,
+    std::function<void(std::string_view const &)> clipboard_set)
 {
 	m_rune = rune;
 	m_ctrl = ctrl;
 	m_shift = shift;
+	m_clipboard = clipboard;
+	m_clipboard_set = clipboard_set;
 }
 
-void ImGui::end() { }
+void ImGui::end()
+{
+	m_rune = false;
+	m_ctrl = false;
+	m_shift = false;
+	m_clipboard = {};
+	m_clipboard_set = nullptr;
+}
 
 void ImGui::set_font(FontHandle font) { m_font = font; }
 
@@ -289,6 +285,15 @@ void ImGui::ime_clear_preedit()
 	state.caret_timer = 0.0;
 }
 
+size_t utf8_length(std::string_view const &s)
+{
+	size_t count = 0;
+	for (unsigned char c : s)
+		if ((c & 0xC0) != 0x80) // continuation bytes
+			++count;
+	return count;
+}
+
 auto ImGui::text_input(usize id, std::pmr::string &str, Rectangle rec,
     TextInputOptions options) -> std::bitset<2>
 {
@@ -479,6 +484,26 @@ auto ImGui::text_input(usize id, std::pmr::string &str, Rectangle rec,
 				submitted = true;
 			}
 			break;
+		case 'v':
+			if (m_ctrl && !m_clipboard.empty()) {
+				if (!options.multiline) {
+					std::string clipboard_no_newlines;
+					for (auto const &ch : m_clipboard) {
+						if (ch == '\n' || ch == '\r')
+							continue;
+						clipboard_no_newlines.push_back(ch);
+					}
+					str.insert(caret_byte, clipboard_no_newlines);
+					state.current_rune_idx
+					    += utf8_length(clipboard_no_newlines);
+				} else {
+					str.insert(caret_byte, m_clipboard);
+					state.current_rune_idx += utf8_length(m_clipboard);
+				}
+				changed = true;
+				request_refresh = true;
+				break;
+			}
 		default:
 			if (m_rune >= 0x20) {
 				auto encoded { encode_utf8(m_rune) };