Binary type switch is slow

fastbinary_test.go

package fastbinary

import (
	"bytes"
	"encoding/binary"
	"io"
	"testing"
)

func BenchmarkInternalBinary_Read(b *testing.B) {
	inbuf := []byte("  \n  \nAccording to all known laws\nof aviation,\n\n  \nthere is no way a bee\nshould be able to fly.\n\n  \nIts wings are too small to get\nits fat little body off the ground.\n\n  \nThe bee, of course, flies anyway\n\n  \nbecause bees don't care\nwhat humans think is impossible.\n\n  \nYellow, black. Yellow, black.\nYellow, black. Yellow, black.\n\n  \nOoh, black and yellow!\nLet's shake it up a little.\n\n  \nBarry! Breakfast is ready!\n\n  \nOoming!\n\n  \nHang on a second.")
	outbuf := int16(0)
	for i := 0; i < b.N; i++ {
		for rds := 0; rds < 10000; rds++ {
			if err := binary.Read(bytes.NewReader(inbuf), binary.LittleEndian, &outbuf); err != nil {
				b.Fatalf("Error reading into buffer: %v\n", err)
			}
		}
	}
}

func BenchmarkFastBinary_Read(b *testing.B) {
	inbuf := []byte("  \n  \nAccording to all known laws\nof aviation,\n\n  \nthere is no way a bee\nshould be able to fly.\n\n  \nIts wings are too small to get\nits fat little body off the ground.\n\n  \nThe bee, of course, flies anyway\n\n  \nbecause bees don't care\nwhat humans think is impossible.\n\n  \nYellow, black. Yellow, black.\nYellow, black. Yellow, black.\n\n  \nOoh, black and yellow!\nLet's shake it up a little.\n\n  \nBarry! Breakfast is ready!\n\n  \nOoming!\n\n  \nHang on a second.")
	outbuf := int16(0)
	for i := 0; i < b.N; i++ {
		for rds := 0; rds < 10000; rds++ {
			if err := BinaryReadNoTypeSwitch(bytes.NewReader(inbuf), &outbuf); err != nil {
				b.Fatalf("Error reading into buffer: %v\n", err)
			}
		}
	}
}

func BinaryReadNoTypeSwitch(r io.Reader, data *int16) error {
	bs := make([]byte, Int16DataSize)
	if _, err := io.ReadFull(r, bs); err != nil {
		return err
	}
	*data = int16(binary.LittleEndian.Uint16(bs))
	return nil
}

Benchmark results:

goos: darwin
goarch: amd64
pkg: ledfx/integrations/airplay2/codec/fastbinary
cpu: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
BenchmarkInternalBinary_Read
BenchmarkInternalBinary_Read-16    	    1615	    643031 ns/op
BenchmarkFastBinary_Read
BenchmarkFastBinary_Read-16        	    2172	    548797 ns/op
PASS