Исходники и презентации

lessons/strings/string_builder_implementation/main.go

@@ -0,0 +1,53 @@
+package main
+
+import "fmt"
+
+type Builder struct {
+	buffer []byte
+}
+
+func NewBuilder() Builder {
+	return Builder{}
+}
+
+func (b *Builder) Grow(capacity int) {
+	if capacity < 0 {
+		return
+	}
+
+	if capacity < len(b.buffer) {
+		b.buffer = b.buffer[:capacity]
+		return
+	}
+
+	buffer := make([]byte, len(b.buffer), capacity)
+	copy(buffer, b.buffer)
+	b.buffer = buffer
+}
+
+func (b *Builder) Write(symbol byte) {
+	b.buffer = append(b.buffer, symbol)
+}
+
+func (b *Builder) At(index int) *byte {
+	if index < 0 || index >= len(b.buffer) {
+		return nil
+	}
+
+	return &b.buffer[index]
+}
+
+func (b *Builder) String() string {
+	return string(b.buffer)
+}
+
+func main() {
+	builder := NewBuilder()
+	builder.Grow(3)
+
+	builder.Write('a')
+	builder.Write('b')
+	builder.Write('c')
+
+	fmt.Println(builder.String())
+}