find_strings

strings.go

package main;

import (
	"fmt"
	"flag"
	"bufio"
	"os"
	"errors"
)

var fileName = flag.String("f", "", "filename")
var unicodeOnly = flag.Bool("u", false, "unicode")

var minLength = 4;
var textUtf = "";
var textAscii = "";

var rangeStart = 0x20;
var rangeEnd = 0x7e
var rangeAdditional map[int]bool = make(map[int]bool)

func main(){
	flag.Parse();

	file, err := os.Open(*fileName)
	if err!=nil {
		panic(err)
	}
	defer file.Close()

	r := bufio.NewReader(file)

	var bcount int64 = 0
	
	fileUtf, err := os.Create("out.txt");
	if err != nil{
		fmt.Println(err.Error())
		return;
	}

	futf := bufio.NewWriter(fileUtf);
	defer futf.Flush()
	defer fileUtf.Close()

	var utfBuffer = []byte{}

	rangeAdditional[0xe4] = true;
	rangeAdditional[0xf6] = true;
	rangeAdditional[0xfc] = true;
	rangeAdditional[0xdc] = true;
	rangeAdditional[0xc4] = true;
	rangeAdditional[0xd6] = true;

	for true {
		b1, err := r.ReadByte();

		if err != nil {
			PrintText(futf,textUtf)
			PrintText(futf,textAscii)

			fmt.Println(err.Error())
			break;
		}
		
		utfBuffer = append(utfBuffer, b1)

		if len(utfBuffer) == 2 {
			letterUtf, errUtf:= checkChar(utfBuffer)
			if errUtf == nil {
				textUtf += letterUtf
			} else{
				PrintText(futf,textUtf)
				textUtf=""
			}

			utfBuffer = utfBuffer[:0]
		}

		if(*unicodeOnly != true){
			letterAscii, errAscii:= checkChar([]byte{b1})
		
			if errAscii == nil {
				textAscii += letterAscii
			} else {
				PrintText(futf,textAscii)
				textAscii = ""
			}
		}

		bcount+=1;
	}

	fmt.Printf("done, read %d bytes", bcount)
}




func checkChar(bytes []byte) (letter string, err error) {
	var letterInt = toInt(bytes)

	if letterInt >= rangeStart && letterInt <= rangeEnd {
		return string(letterInt),nil
	}

	_, ok := rangeAdditional[letterInt]
	if ok {
		return string(letterInt),nil
	}

	return "", errors.New("garbage")
}

func PrintText(f *bufio.Writer, text string){
	if len(text) >= minLength{
		//fmt.Println(text)
		f.WriteString(text)
		f.WriteString("\n")
	}
}


func toInt(bytes []byte) int{
	var num int = 0;
	var maxBytes = len(bytes);

	if maxBytes > 4 {
		maxBytes = 4
	}

	for k:=0;k<maxBytes;k++ {
		num += int(bytes[k]) << (uint(maxBytes-k-1)*8);
	}

	return num;
}