test: add benchmark to compare float array encoding

stream/enc_bench_test.go

@@ -0,0 +1,65 @@
+package stream_test
+
+import (
+	"io"
+	"math/rand"
+	"testing"
+
+	"github.com/go-faster/jx"
+	"github.com/go-faster/jx/stream"
+)
+
+func encodeFloats(e *jx.Encoder, arr []float64) {
+	e.ArrStart()
+	for _, v := range arr {
+		e.Float64(v)
+	}
+	e.ArrEnd()
+}
+
+func encodeFloatsStream[W io.Writer](e *stream.Encoder[W], arr []float64) bool {
+	if e.ArrStart() {
+		return true
+	}
+	for _, v := range arr {
+		if e.Float64(v) {
+			return true
+		}
+	}
+	return e.ArrEnd()
+}
+
+func BenchmarkEncodeFloats(b *testing.B) {
+	const N = 100_000
+	arr := make([]float64, N)
+	for i := 0; i < N; i++ {
+		arr[i] = rand.NormFloat64()
+	}
+	size := func() int64 {
+		var enc jx.Encoder
+		encodeFloats(&enc, arr)
+		return int64(len(enc.Bytes()))
+	}()
+	b.Logf("Size: %d bytes", size)
+
+	b.Run("Buffered", func(b *testing.B) {
+		b.SetBytes(size)
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				// Notice: no buffer reuse.
+				var enc jx.Encoder
+				encodeFloats(&enc, arr)
+			}
+		})
+	})
+	b.Run("Stream", func(b *testing.B) {
+		b.SetBytes(size)
+		b.RunParallel(func(pb *testing.PB) {
+			enc := stream.NewEncoder(io.Discard)
+			for pb.Next() {
+				enc.Reset(io.Discard)
+				encodeFloatsStream(enc, arr)
+			}
+		})
+	})
+}