open/read vs open/mmap vs open/bufio.read on golang.

open_read.go

package main

import (
	"fmt"
	"log"
	"os"
)

func main() {
	if len(os.Args) < 2 {
		return
	}
	path := os.Args[1]

	f, err := os.Open(path)
	if err != nil {
		log.Fatal(err)
	}
	fi, err := f.Stat()
	if err != nil {
		log.Fatal(err)
	}

	buf := make([]byte, fi.Size())
	_, err = f.Read(buf)
	if err != nil {
		log.Fatal(err)
	}

	cnt := 0
	for _, b := range buf {
		if b == 0x00 {
			cnt++
		}
	}

	f.Close()

	fmt.Printf("%s: size=%d cnt=%d\n", path, fi.Size(), cnt);
}