Up to step 71 in tutorial

kilo

@@ -7,14 +7,20 @@ require_once __DIR__ . '/src/constants.php';
 require_once __DIR__ . '/src/functions.php';
 require_once __DIR__ . '/src/Editor.php';
 
-function main(): int
+function main(int $argc, array $argv): int
 {
 	global $ffi;
 
 	enableRawMode();
 
 	// ob_start();
-	$editor = new Editor($ffi);
+	$editor = Editor::new($ffi);
+
+	if ($argc >= 2)
+	{
+		$editor->open($argv[1]);
+	}
+
 
 	// Input Loop
 	while (true)
@@ -28,4 +34,4 @@ function main(): int
 }
 
 //! Init
-main();
+main($argc, $argv);

src/Editor.php

@@ -16,16 +16,42 @@ class Key {
 	public const PAGE_DOWN = 'PAGE_DOWN';
 }
 
+class Row {
+	public string $chars;
+
+	public static function new(string $chars): self
+	{
+		return new self($chars);
+	}
+
+	private function __construct($chars)
+	{
+		$this->chars = $chars;
+	}
+}
+
 class Editor {
 	private FFI $ffi;
 
 	protected int $cursorx = 0;
 	protected int $cursory = 0;
+	protected int $rowoff = 0;
+	protected int $coloff = 0;
 	protected int $screenRows = 0;
 	protected int $screenCols = 0;
 	protected string $ab = '';
 
-	public function __construct($ffi)
+	/**
+	 * Array of Row objects
+	 */
+	protected array $rows = [];
+
+	public static function new(FFI $ffi): Editor
+	{
+		return new self($ffi);
+	}
+
+	private function __construct($ffi)
 	{
 		$this->ffi = $ffi;
 
@@ -135,15 +161,63 @@ class Editor {
 		return true;
 	}
 
+	// ------------------------------------------------------------------------
+	// ! Row Operations
+	// ------------------------------------------------------------------------
+
+	protected function appendRow(string $s): void
+	{
+		$this->rows[] = Row::new($s);
+	}
+
+	// ------------------------------------------------------------------------
+	// ! File I/O
+	// ------------------------------------------------------------------------
+
+	public function open(string $filename): void
+	{
+		$baseFile = basename($filename);
+		$basePath = str_replace($baseFile, '', $filename);
+		$path = (is_dir($basePath)) ? $basePath : getcwd();
+
+		$fullname = $path . '/' . $baseFile;
+
+
+		$handle = fopen($fullname, 'rb');
+
+		while (($line = fgets($handle)) !== FALSE)
+		{
+			$this->appendRow($line);
+		}
+
+		fclose($handle);
+	}
+
 	// ------------------------------------------------------------------------
 	// ! Output
 	// ------------------------------------------------------------------------
 
+	protected function scroll(): void
+	{
+		if ($this->cursory < $this->rowoff)
+		{
+			$this->rowoff = $this->cursory;
+		}
+
+		if ($this->cursory >= $this->rowoff + $this->screenRows)
+		{
+			$this->rowoff = $this->cursory - $this->screenRows + 1;
+		}
+	}
+
 	protected function drawRows(): void
 	{
 		for ($y = 0; $y < $this->screenRows; $y++)
 		{
-			if ($y === ($this->screenRows / 3))
+			$filerow = $y + $this->rowoff;
+			if ($filerow >= count($this->rows))
+			{
+				if (count($this->rows) === 0 && $y === $this->screenRows / 3)
 				{
 					$welcome = sprintf('PHP Kilo editor -- version %s', KILO_VERSION);
 					$welcomelen = strlen($welcome);
@@ -164,12 +238,26 @@ class Editor {
 					}
 
 					$this->ab .= substr($welcome, 0, $welcomelen);
-
 				}
 				else
 				{
 					$this->ab .= '~';
 				}
+			}
+			else
+			{
+				$len = strlen($this->rows[$filerow]->chars) - $this->coloff;
+				if ($len < 0)
+				{
+					$len = 0;
+				}
+				if ($len > $this->screenCols)
+				{
+					$len = $this->screenCols;
+				}
+
+				$this->ab .= substr($this->rows[$filerow]->chars, $this->coloff, $len);
+			}
 
 			$this->ab .= "\x1b[K"; // Clear the current line
 			if ($y < $this->screenRows - 1)
@@ -181,6 +269,8 @@ class Editor {
 
 	public function refreshScreen(): void
 	{
+		$this->scroll();
+
 		$this->ab = '';
 
 		$this->ab .= "\x1b[?25l"; // Hide the cursor
@@ -189,7 +279,7 @@ class Editor {
 		$this->drawRows();
 
 		// Specify the current cursor position
-		$this->ab .= sprintf("\x1b[%d;%dH", $this->cursory + 1, $this->cursorx + 1);
+		$this->ab .= sprintf("\x1b[%d;%dH", ($this->cursory - $this->rowoff) + 1, $this->cursorx + 1);
 
 		$this->ab .= "\x1b[?25h"; // Show the cursor
 
@@ -226,7 +316,7 @@ class Editor {
 			break;
 
 			case Key::ARROW_DOWN:
-				if ($this->cursory !== $this->screenRows - 1)
+				if ($this->cursory < count($this->rows))
 				{
 					$this->cursory++;
 				}
@@ -255,13 +345,7 @@ class Editor {
 
 			case Key::PAGE_UP:
 			case Key::PAGE_DOWN:
-			{
-				$times = $this->screenRows;
-				while ($times--)
-				{
-					$this->moveCursor($c === Key::PAGE_UP ? Key::ARROW_UP : Key::ARROW_DOWN);
-				}
-			}
+				$this->pageUpOrDown($c);
 			break;
 
 			case Key::ARROW_UP:
@@ -274,4 +358,13 @@ class Editor {
 
 		return $c;
 	}
+
+	private function pageUpOrDown(string $c):void
+	{
+		$times = $this->screenRows;
+		while ($times--)
+		{
+			$this->moveCursor($c === Key::PAGE_UP ? Key::ARROW_UP : Key::ARROW_DOWN);
+		}
+	}
 }