Handout

kernel/arch/textwindow.cc

@@ -0,0 +1,129 @@
+#include "textwindow.h"
+
+#include "../utils/math.h"
+
+TextWindow::TextWindow(unsigned from_col, unsigned to_col, unsigned from_row,
+					   unsigned to_row, bool use_cursor)
+	: from_col(from_col),
+	  to_col(to_col),
+	  from_row(from_row),
+	  to_row(to_row),
+	  use_cursor(use_cursor),
+	  pos_x(from_col),
+	  pos_y(from_row) {
+	if (to_col > from_col && to_row > from_row) {
+		reset();
+	}
+}
+
+void TextWindow::setPos(unsigned rel_x, unsigned rel_y) {
+	unsigned abs_x = rel_x + from_col;
+	unsigned abs_y = rel_y + from_row;
+
+	// Check if visible
+	if (abs_x < to_col && abs_y < to_row) {
+		if (use_cursor) {
+			CGA::setCursor(abs_x, abs_y);
+		} else {
+			pos_x = abs_x;
+			pos_y = abs_y;
+		}
+	}
+}
+
+void TextWindow::getPos(unsigned& rel_x, unsigned& rel_y) const {
+	unsigned abs_x = pos_x;
+	unsigned abs_y = pos_y;
+
+	if (use_cursor) {
+		CGA::getCursor(abs_x, abs_y);
+	}
+
+	rel_x = Math::min(Math::max(abs_x, from_col), to_col - 1) - from_col;
+	rel_y = Math::min(Math::max(abs_y, from_row), to_row - 1) - from_row;
+}
+
+void TextWindow::setPos(int rel_x, int rel_y) {
+	int x = rel_x < 0 ? rel_x + to_col - from_col : rel_x;
+	int y = rel_y < 0 ? rel_y + to_row - from_row : rel_y;
+
+	if (x >= 0 && y >= 0) {
+		setPos(static_cast<unsigned>(x), static_cast<unsigned>(y));
+	}
+}
+
+void TextWindow::getPos(int& rel_x, int& rel_y) const {
+	unsigned x;
+	unsigned y;
+	getPos(x, y);
+	rel_x = static_cast<int>(x);
+	rel_y = static_cast<int>(y);
+}
+
+void TextWindow::print(const char* str, size_t length, CGA::Attribute attrib) {
+	// Get position
+	unsigned abs_x = pos_x;
+	unsigned abs_y = pos_y;
+
+	if (use_cursor) {
+		CGA::getCursor(abs_x, abs_y);
+	}
+
+	// Print each character
+	while (length > 0) {
+		switch (*str) {
+			case '\n':
+				abs_x = from_col;
+				abs_y++;
+				break;
+
+			case '\r':
+				abs_x = from_col;
+				break;
+
+			default:
+				show(abs_x, abs_y, *str, attrib);
+				abs_x++;
+				if (abs_x >= to_col) {
+					abs_x = from_col;
+					abs_y++;
+				}
+				break;
+		}
+		str++;
+		if (abs_y >= to_row) {
+			scrollUp();
+			abs_y--;
+		}
+		length--;
+	}
+	// Write position back
+	if (use_cursor) {
+		CGA::setCursor(abs_x, abs_y);
+	} else {
+		pos_x = abs_x;
+		pos_y = abs_y;
+	}
+}
+
+void TextWindow::reset(char character, CGA::Attribute attrib) {
+	for (unsigned abs_y = from_row; abs_y < to_row; ++abs_y) {
+		for (unsigned abs_x = from_col; abs_x < to_col; ++abs_x) {
+			show(abs_x, abs_y, character, attrib);
+		}
+	}
+	setPos(0, 0);
+}
+
+void TextWindow::scrollUp() const {
+	for (unsigned y = from_row + 1; y < to_row; ++y) {
+		for (unsigned x = from_col; x < to_col; ++x) {
+			unsigned pos = (y * CGA::COLUMNS) + x;
+			show(x, y - 1, CGA::TEXT_BUFFER_BASE[pos].character,
+				 CGA::TEXT_BUFFER_BASE[pos].attribute);
+		}
+	}
+	for (unsigned x = from_col; x < to_col; ++x) {
+		CGA::show(x, to_row - 1, ' ');
+	}
+}