implemented generic buffer

buffer.go

@@ -1,76 +1,72 @@
 package buf2d
 
 import (
-	"fmt"
 	"strings"
 )
 
-// Buffer is a 2-dimensional rune buffer
+// Buffer is a 2-dimensional buffer
-type Buffer struct {
+type Buffer[T any] struct {
-	data   [][]fmt.Stringer
+	data       [][]T
-	width  int
+	width      int
-	height int
+	height     int
-	parent *Buffer
+	parent     *Buffer[T]
+	StringFunc func(T) string
 }
 
 // NewBuffer makes a new buffer with the given dimensions
-func NewBuffer(width, height int) *Buffer {
+func NewBuffer[T any](width, height int, defaultValue T) *Buffer[T] {
-	b := make([][]fmt.Stringer, height)
+	b := make([][]T, height)
 	for y := range b {
-		b[y] = make([]fmt.Stringer, width)
+		b[y] = make([]T, width)
 		for x := range b[y] {
-			b[y][x] = spaceStringer
+			b[y][x] = defaultValue
 		}
 	}
 
-	return &Buffer{
+	return &Buffer[T]{
-		data:   b,
+		data:       b,
-		width:  width,
+		width:      width,
-		height: height,
+		height:     height,
-		parent: nil,
+		parent:     nil,
+		StringFunc: MakeDefaultStringFunc[T](),
 	}
 }
 
-func (b *Buffer) x(x int) int {
+func (b *Buffer[T]) x(x int) int {
 	return limit(x, 0, b.width-1)
 }
 
-func (b *Buffer) y(y int) int {
+func (b *Buffer[T]) y(y int) int {
 	return limit(y, 0, b.height-1)
 }
 
-// Set sets the fmt.Stringer at position (x,y) to c
+// Set sets the value at position (x,y) to c
-func (b *Buffer) Set(x, y int, c fmt.Stringer) {
+func (b *Buffer[T]) Set(x, y int, v T) {
-	b.data[b.y(y)][b.x(x)] = c
+	b.data[b.y(y)][b.x(x)] = v
 }
 
-// SetRune sets the fmt.Stringer at position (x,y) to rn
+// Get returns the value at position (x,y)
-func (b *Buffer) SetRune(x, y int, rn rune) {
+func (b *Buffer[T]) Get(x, y int) T {
-	b.data[b.y(y)][b.x(x)] = newStringerFromRune(rn)
-}
-
-// Get returns the fmt.Stringer at position (x,y)
-func (b *Buffer) Get(x, y int) fmt.Stringer {
 	return b.data[y][x]
 }
 
 // Size returns width and height of b
-func (b *Buffer) Size() (w, h int) {
+func (b *Buffer[T]) Size() (w, h int) {
 	return b.width, b.height
 }
 
 // Width returns the width of b
-func (b *Buffer) Width() int {
+func (b *Buffer[T]) Width() int {
 	return b.width
 }
 
 // Height returns the height of b
-func (b *Buffer) Height() int {
+func (b *Buffer[T]) Height() int {
 	return b.height
 }
 
-// ForEach calls f for every rune in this buffer
+// ForEach calls f for every value in this buffer
-func (b *Buffer) ForEach(f func(x, y int, c fmt.Stringer)) {
+func (b *Buffer[T]) ForEach(f func(x, y int, v T)) {
 	for y, col := range b.data {
 		for x, v := range col {
 			f(x, y, v)
@@ -78,11 +74,11 @@ func (b *Buffer) ForEach(f func(x, y int, c fmt.Stringer)) {
 	}
 }
 
-func (b *Buffer) String() string {
+func (b *Buffer[T]) String() string {
 	s := new(strings.Builder)
 	for ci, col := range b.data {
 		for _, v := range col {
-			s.WriteString(fmt.Sprintf("%v", v))
+			s.WriteString(b.StringFunc(v))
 		}
 		if ci != len(b.data)-1 {
 			s.WriteRune('\n')
@@ -95,7 +91,7 @@ func (b *Buffer) String() string {
 // Modifying the main buffer or the sub buffer will modify the other one as well
 // This method can be used recursively
 // If the given dimensions don't fit in the parent buffer, it will be truncated
-func (b *Buffer) Sub(x, y, w, h int) *Buffer {
+func (b *Buffer[T]) Sub(x, y, w, h int) *Buffer[T] {
 	// sanitize inputs
 	x = limit(x, 0, b.width-1)
 	y = limit(y, 0, b.height-1)
@@ -103,17 +99,18 @@ func (b *Buffer) Sub(x, y, w, h int) *Buffer {
 	h = limit(h, 1, b.height-y)
 
 	// make slice references
-	data := make([][]fmt.Stringer, h)
+	data := make([][]T, h)
 	for dy := 0; dy < h; dy++ {
 		col := b.data[y+dy]
 		data[dy] = col[x : x+w]
 	}
 
 	// make buffer
-	return &Buffer{
+	return &Buffer[T]{
-		data:   data,
+		data:       data,
-		width:  w,
+		width:      w,
-		height: h,
+		height:     h,
-		parent: b,
+		parent:     b,
+		StringFunc: b.StringFunc,
 	}
 }

buffer_test.go

@@ -7,13 +7,13 @@ import (
 )
 
 func TestSub(t *testing.T) {
-	b := NewBuffer(10, 10)
+	b := NewBuffer(10, 10, ' ')
 	s := b.Sub(1, 1, b.Width()-1, b.Height()-1)
-	b.SetRune(5, 1, 'a')
+	b.Set(5, 1, 'a')
-	s.SetRune(5, 5, 'b')
+	s.Set(5, 5, 'b')
-	b.WriteString("Hello world", 1, 2)
+	WriteString(b, "Hello world", 1, 2)
 
 	fmt.Println(b)
-	fmt.Println(strings.Repeat("-", 20))
+	fmt.Println(strings.Repeat("-", 10))
 	fmt.Println(s)
 }

go.mod

@@ -1,3 +1,3 @@
 module git.tordarus.net/Tordarus/buf2d
 
-go 1.15
+go 1.18

utils.go

@@ -1,6 +1,9 @@
 package buf2d
 
-import "fmt"
+import (
+	"fmt"
+	"reflect"
+)
 
 func limit(v, min, max int) int {
 	return getmax(getmin(v, max), min)
@@ -20,21 +23,18 @@ func getmin(x, y int) int {
 	return y
 }
 
-type stringerImpl string
+func MakeDefaultStringFunc[T any]() func(T) string {
+	if reflect.TypeOf(new(T)).Elem() == reflect.TypeOf(new(rune)).Elem() {
+		return func(value T) string {
+			return string((interface{}(value)).(rune))
+		}
+	} else if reflect.TypeOf(new(T)).Elem() == reflect.TypeOf(new(string)).Elem() {
+		return func(value T) string {
+			return (interface{}(value)).(string)
+		}
+	}
 
-func (s *stringerImpl) String() string {
+	return func(value T) string {
-	return string(*s)
+		return fmt.Sprintf("%v", value)
+	}
 }
-
-func newStringer(str string) fmt.Stringer {
-	var impl stringerImpl = stringerImpl(str)
-	return &impl
-}
-
-func newStringerFromRune(rn rune) fmt.Stringer {
-	return newStringer(string(rn))
-}
-
-var (
-	spaceStringer = newStringer(" ")
-)

write_string.go

@@ -1,19 +1,18 @@
 package buf2d
 
 import (
-	"fmt"
 	"strings"
 )
 
 // WriteString writes a whole string to the buffer at position (x,y)
 // no word wrap is applied at all. If the string does not fit, it will be truncated
-func (b *Buffer) WriteString(str string, x, y int) {
+func WriteString(b *Buffer[rune], str string, x, y int) {
 	dx := x
 	for _, r := range str {
 		if dx >= b.width {
 			return
 		}
-		b.Set(dx, y, newStringerFromRune(r))
+		b.Set(dx, y, r)
 		dx++
 	}
 }
@@ -21,22 +20,21 @@ func (b *Buffer) WriteString(str string, x, y int) {
 // WriteMultiLineString writes a multi-line string to the buffer at position (x,y)
 // no word wrap is applied at all. If a line does not fit horizontally, it will be truncated
 // All lines which do not fit vertically will be truncated as well
-func (b *Buffer) WriteMultiLineString(str string, x, y int) {
+func WriteMultiLineString(b *Buffer[rune], str string, x, y int) {
 	lines := strings.Split(str, "\n")
 	for dy, line := range lines {
 		if dy >= b.height {
 			return
 		}
-
+		WriteString(b, line, x, y+dy)
-		b.WriteString(line, x, y+dy)
 	}
 }
 
 // Fill fills the whole buffer with c
-func (b *Buffer) Fill(c fmt.Stringer) {
+func (b *Buffer[T]) Fill(value T) {
 	for _, col := range b.data {
 		for ri := range col {
-			col[ri] = c
+			col[ri] = value
 		}
 	}
 }