Merge pull request #10 from achilleasa/improve-tty-and-fix-fmt-bugs

Improve tty and fix fmt bugs

kernel/driver/tty/tty.go

@@ -5,6 +5,7 @@ import "io"
 // Tty is implemented by objects that can register themselves as ttys.
 type Tty interface {
 	io.Writer
+	io.ByteWriter
 
 	// Position returns the current cursor position (x, y).
 	Position() (uint16, uint16)

kernel/driver/tty/vt.go

@@ -5,6 +5,7 @@ import "github.com/achilleasa/gopher-os/kernel/driver/video/console"
 const (
 	defaultFg = console.LightGrey
 	defaultBg = console.Black
+	tabWidth  = 4
 )
 
 // Vt implements a simple terminal that can process LF and CR characters. The
@@ -59,24 +60,45 @@ func (t *Vt) SetPosition(x, y uint16) {
 
 // Write implements io.Writer.
 func (t *Vt) Write(data []byte) (int, error) {
-	attr := t.curAttr
 	for _, b := range data {
+		t.WriteByte(b)
+	}
+
+	return len(data), nil
+}
+
+// Write implements io.ByteWriter.
+func (t *Vt) WriteByte(b byte) error {
 	switch b {
 	case '\r':
 		t.cr()
 	case '\n':
 		t.cr()
 		t.lf()
-		default:
-			t.cons.Write(b, attr, t.curX, t.curY)
+	case '\b':
+		if t.curX > 0 {
+			t.cons.Write(' ', t.curAttr, t.curX, t.curY)
+			t.curX--
+		}
+	case '\t':
+		for i := 0; i < tabWidth; i++ {
+			t.cons.Write(' ', t.curAttr, t.curX, t.curY)
 			t.curX++
 			if t.curX == t.width {
+				t.cr()
 				t.lf()
 			}
 		}
+	default:
+		t.cons.Write(b, t.curAttr, t.curX, t.curY)
+		t.curX++
+		if t.curX == t.width {
+			t.cr()
+			t.lf()
+		}
 	}
 
-	return len(data), nil
+	return nil
 }
 
 // cls clears the terminal.

kernel/driver/tty/vt_test.go

@@ -44,7 +44,12 @@ func TestWrite(t *testing.T) {
 
 	vt.Clear()
 	vt.SetPosition(0, 1)
-	vt.Write([]byte("12\n3\n4\r56"))
+	vt.Write([]byte("12\n\t3\n4\r567\b8"))
+
+	// Tab spanning rows
+	vt.SetPosition(78, 4)
+	vt.WriteByte('\t')
+	vt.WriteByte('9')
 
 	// Trigger scroll
 	vt.SetPosition(79, 24)
@@ -56,9 +61,22 @@ func TestWrite(t *testing.T) {
 	}{
 		{0, 0, '1'},
 		{1, 0, '2'},
-		{0, 1, '3'},
+		// tabs
+		{0, 1, ' '},
+		{1, 1, ' '},
+		{2, 1, ' '},
+		{3, 1, ' '},
+		{4, 1, '3'},
+		// tab spanning 2 rows
+		{78, 3, ' '},
+		{79, 3, ' '},
+		{0, 4, ' '},
+		{1, 4, ' '},
+		{2, 4, '9'},
+		//
 		{0, 2, '5'},
 		{1, 2, '6'},
+		{2, 2, '8'}, // overwritten by BS
 		{79, 23, '!'},
 	}
 

kernel/kfmt/early/early_fmt.go

@@ -7,7 +7,7 @@ var (
 	errWrongArgType = []byte("%!(WRONGTYPE)")
 	errNoVerb       = []byte("%!(NOVERB)")
 	errExtraArg     = []byte("%!(EXTRA)")
-	padding         = []byte{' '}
+	padding         = byte(' ')
 	trueValue       = []byte("true")
 	falseValue      = []byte("false")
 )
@@ -62,7 +62,9 @@ func Printf(format string, args ...interface{}) {
 		}
 
 		if blockStart < blockEnd {
-			hal.ActiveTerminal.Write([]byte(format[blockStart:blockEnd]))
+			for i := blockStart; i < blockEnd; i++ {
+				hal.ActiveTerminal.WriteByte(format[i])
+			}
 		}
 
 		// Scan til we hit the format character
@@ -109,7 +111,9 @@ func Printf(format string, args ...interface{}) {
 	}
 
 	if blockStart != blockEnd {
-		hal.ActiveTerminal.Write([]byte(format[blockStart:blockEnd]))
+		for i := blockStart; i < blockEnd; i++ {
+			hal.ActiveTerminal.WriteByte(format[i])
+		}
 	}
 
 	// Check for unused args
@@ -139,23 +143,25 @@ func fmtBool(v interface{}) {
 // padding specified by padLen. This function uses hal.ActiveTerminal for its
 // output.
 func fmtString(v interface{}, padLen int) {
-	var sval []byte
-
 	switch castedVal := v.(type) {
 	case string:
-		sval = []byte(castedVal)
+		fmtRepeat(padding, padLen-len(castedVal))
+		for i := 0; i < len(castedVal); i++ {
+			hal.ActiveTerminal.WriteByte(castedVal[i])
+		}
 	case []byte:
-		sval = castedVal
+		fmtRepeat(padding, padLen-len(castedVal))
+		hal.ActiveTerminal.Write(castedVal)
 	default:
 		hal.ActiveTerminal.Write(errWrongArgType)
-		return
 	}
+}
 
-	for pad := padLen - len(sval); pad > 0; pad-- {
-		hal.ActiveTerminal.Write(padding)
+// fmtRepeat writes count bytes with value ch to the hal.ActiveTerminal.
+func fmtRepeat(ch byte, count int) {
+	for i := 0; i < count; i++ {
+		hal.ActiveTerminal.WriteByte(ch)
 	}
-
-	hal.ActiveTerminal.Write(sval)
 }
 
 // fmtInt prints out a formatted version of v in the requested base, applying the