quotes_count.go

package quamina

import (
	"fmt"
	"io"
	"os"
	"testing"
)

var (
	topCount int
	event    []byte
)

type quotesCounter struct {
	event      []byte // event being processed, treated as immutable
	eventIndex int    // current byte index into the event
	length     int
}

func (qc *quotesCounter) countQuotesWithStepping(event []byte) int {
	qc.eventIndex = 0
	qc.event = event
	qc.length = len(qc.event)

	count := 0

	for {
		ch := qc.ch()

		if ch == '"' {
			count++
		}

		if qc.step() != nil {
			return count
		}
	}
}

func (qc *quotesCounter) countQuotesWithFor(event []byte) int {
	qc.eventIndex = 0
	qc.event = event

	count := 0
	index := 0

	for index < len(qc.event) {
		ch := qc.event[index]

		if ch == '"' {
			count++
		}

		index++
	}

	return count
}

// ch fetches the next byte from the event. It doesn't check array bounds,
// so it's the caller's responsibility to ensure we haven't run off the end of the event.
func (qc *quotesCounter) ch() byte {
	return qc.event[qc.eventIndex]
}

// step advances the event pointer and returns an error if you've run off the end of the event
func (qc *quotesCounter) step() error {
	qc.eventIndex++

	if qc.eventIndex >= qc.length {
		// In real qumina we return good error, since we are reading till end of input
		// we can return EOF, which is more efficient than doing `fmt.Errorf`
		return io.EOF
	}

	return nil
}

func init() {
	var err error
	event, err = os.ReadFile("./testdata/status.json")
	if err != nil {
		panic(fmt.Sprintf("Failed to read file: %s", err))
	}
}

func Benchmark_QuotesCount_Stepping(b *testing.B) {
	var localCount int

	counter := &quotesCounter{}
	count := counter.countQuotesWithStepping(event)
	b.Logf("Quotes count: %d", count)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		count := counter.countQuotesWithStepping(event)
		localCount = count
	}

	topCount = localCount
}

func Benchmark_QuotesCount_For(b *testing.B) {
	var localCount int

	counter := &quotesCounter{}
	count := counter.countQuotesWithFor(event)
	b.Logf("Quotes count: %d", count)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		count := counter.countQuotesWithFor(event)
		localCount = count
	}

	topCount = localCount
}

results.md

 ❯ go test  -benchmem -run="^$" -bench "^Benchmark_Quotes" 
goos: darwin
goarch: arm64
pkg: github.com/timbray/quamina
Benchmark_QuotesCount_Stepping-10    	   57076	     19373 ns/op	       0 B/op	       0 allocs/op
--- BENCH: Benchmark_QuotesCount_Stepping-10
    counting_quotes_bench_test.go:93: Quotes count: 642
    counting_quotes_bench_test.go:93: Quotes count: 642
    counting_quotes_bench_test.go:93: Quotes count: 642
    counting_quotes_bench_test.go:93: Quotes count: 642
Benchmark_QuotesCount_For-10         	  393404	      2998 ns/op	       0 B/op	       0 allocs/op
--- BENCH: Benchmark_QuotesCount_For-10
    counting_quotes_bench_test.go:110: Quotes count: 642
    counting_quotes_bench_test.go:110: Quotes count: 642
    counting_quotes_bench_test.go:110: Quotes count: 642
    counting_quotes_bench_test.go:110: Quotes count: 642
PASS
ok  	github.com/timbray/quamina	2.763s