gobench-1

package bench

import (
	"bufio"
	"errors"
	"fmt"
	"os"
	"strings"
	"unicode/utf8"
)

const (
	bufferSize = 100
)

func Find(path, s string) (string, error) {
	if len(s) == 0 {
		return "", errors.New("")
	}

	f, err := os.Open(path)
	if err != nil {
		return "", err
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)

	row := 1
	matches := make([]string, 0)
	for scanner.Scan() {
		line := scanner.Text()
		colOffset := 0
		first, _ := utf8.DecodeRuneInString(s)
		for col := strings.IndexRune(line, first); col > -1 && line[colOffset+col:len(s)] == s; col = strings.IndexRune(line[colOffset:], first) {
			matches = append(matches, fmt.Sprintf("%d:%d", row, col+colOffset))
			colOffset += col + 1
		}
		row++
	}
	return strings.Join(matches, ","), nil
}