commit 2b37461b54ceaf4485943941833d4f7e9648e22f
Author: Timon Ringwald <timon.ringwald@m2xpert.com>
Date:   Thu Oct 1 13:14:36 2020 +0200

    initial commit

diff --git a/buffer.go b/buffer.go
new file mode 100644
index 0000000..af46f28
--- /dev/null
+++ b/buffer.go
@@ -0,0 +1,100 @@
+package buf2d
+
+import (
+	"strings"
+)
+
+// Buffer is a 2-dimensional rune buffer
+type Buffer struct {
+	data   [][]rune
+	width  int
+	height int
+	parent *Buffer
+}
+
+// NewBuffer makes a new buffer with the given dimensions
+func NewBuffer(width, height int) *Buffer {
+	b := make([][]rune, width)
+	for x := range b {
+		b[x] = make([]rune, height)
+		for y := range b[x] {
+			b[x][y] = ' '
+		}
+	}
+
+	return &Buffer{
+		data:   b,
+		width:  width,
+		height: height,
+		parent: nil,
+	}
+}
+
+func (b *Buffer) Set(x, y int, c rune) {
+	b.data[x][y] = c
+}
+
+func (b *Buffer) Get(x, y int) rune {
+	return b.data[x][y]
+}
+
+func (b *Buffer) Size() (w, h int) {
+	return b.width, b.height
+}
+
+func (b *Buffer) Width() int {
+	return b.width
+}
+
+func (b *Buffer) Height() int {
+	return b.height
+}
+
+// Draw calls drawFunc for every rune in this buffer
+func (b *Buffer) Draw(drawFunc func(x, y int, c rune)) {
+	for x, row := range b.data {
+		for y, char := range row {
+			drawFunc(x, y, char)
+		}
+	}
+}
+
+func (b *Buffer) String() string {
+	s := new(strings.Builder)
+	for ri, row := range b.data {
+		for _, char := range row {
+			s.WriteRune(char)
+		}
+		if ri != len(b.data)-1 {
+			s.WriteRune('\n')
+		}
+	}
+	return s.String()
+}
+
+// Sub returns a buffer which is completely contained in this buffer
+// 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 {
+	// sanitize inputs
+	x = limit(x, 0, b.width-1)
+	y = limit(y, 0, b.height-1)
+	w = limit(w, 1, b.width-x)
+	h = limit(h, 1, b.height-y)
+
+	// make slice references
+	data := make([][]rune, w)
+	for dx := x; dx < x+w-1; dx++ {
+		row := b.data[dx]
+		data[dx] = row[y : y+w]
+	}
+
+	// make buffer
+	return &Buffer{
+		data:   data,
+		width:  w,
+		height: h,
+		parent: b,
+	}
+}
diff --git a/buffer_sub_test.go b/buffer_sub_test.go
new file mode 100644
index 0000000..c5df613
--- /dev/null
+++ b/buffer_sub_test.go
@@ -0,0 +1,16 @@
+package buf2d
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestSub(t *testing.T) {
+	b := NewBuffer(10, 10)
+	s := b.Sub(1, 1, b.Width()-1, b.Height()-1)
+	b.Set(5, 5, 'a')
+	s.Set(5, 5, 'b')
+
+	fmt.Println(b)
+	fmt.Println(s)
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..42c54d9
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.tordarus.net/tordarus/buf2d
+
+go 1.15
diff --git a/utils.go b/utils.go
new file mode 100644
index 0000000..0c3a776
--- /dev/null
+++ b/utils.go
@@ -0,0 +1,19 @@
+package buf2d
+
+func limit(v, min, max int) int {
+	return getmax(getmin(v, max), min)
+}
+
+func getmax(x, y int) int {
+	if x > y {
+		return x
+	}
+	return y
+}
+
+func getmin(x, y int) int {
+	if x < y {
+		return x
+	}
+	return y
+}