main.go

package main

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

func main() {
	if len(os.Args)!=2 {
		log.Fatal("Which file you want to convert ?")
	}
	fmt.Println("Converting "+os.Args[1])
	convert(os.Args[1])
	fmt.Println("Done.")
}
func encrypt(offset int, buf []byte, len int) int {
	if offset < 0 {
		return -1
	}
	for i := 0; i < len; i++ {
		buf[i] ^= mapL(offset + i)
	}
	return 0
}

func mapL(v int) byte {
	key := []byte{
		0x77, 0x48, 0x32, 0x73, 0xDE, 0xF2, 0xC0, 0xC8, 0x95, 0xEC, 0x30, 0xB2,
		0x51, 0xC3, 0xE1, 0xA0, 0x9E, 0xE6, 0x9D, 0xCF, 0xFA, 0x7F, 0x14, 0xD1,
		0xCE, 0xB8, 0xDC, 0xC3, 0x4A, 0x67, 0x93, 0xD6, 0x28, 0xC2, 0x91, 0x70,
		0xCA, 0x8D, 0xA2, 0xA4, 0xF0, 0x08, 0x61, 0x90, 0x7E, 0x6F, 0xA2, 0xE0,
		0xEB, 0xAE, 0x3E, 0xB6, 0x67, 0xC7, 0x92, 0xF4, 0x91, 0xB5, 0xF6, 0x6C,
		0x5E, 0x84, 0x40, 0xF7, 0xF3, 0x1B, 0x02, 0x7F, 0xD5, 0xAB, 0x41, 0x89,
		0x28, 0xF4, 0x25, 0xCC, 0x52, 0x11, 0xAD, 0x43, 0x68, 0xA6, 0x41, 0x8B,
		0x84, 0xB5, 0xFF, 0x2C, 0x92, 0x4A, 0x26, 0xD8, 0x47, 0x6A, 0x7C, 0x95,
		0x61, 0xCC, 0xE6, 0xCB, 0xBB, 0x3F, 0x47, 0x58, 0x89, 0x75, 0xC3, 0x75,
		0xA1, 0xD9, 0xAF, 0xCC, 0x08, 0x73, 0x17, 0xDC, 0xAA, 0x9A, 0xA2, 0x16,
		0x41, 0xD8, 0xA2, 0x06, 0xC6, 0x8B, 0xFC, 0x66, 0x34, 0x9F, 0xCF, 0x18,
		0x23, 0xA0, 0x0A, 0x74, 0xE7, 0x2B, 0x27, 0x70, 0x92, 0xE9, 0xAF, 0x37,
		0xE6, 0x8C, 0xA7, 0xBC, 0x62, 0x65, 0x9C, 0xC2, 0x08, 0xC9, 0x88, 0xB3,
		0xF3, 0x43, 0xAC, 0x74, 0x2C, 0x0F, 0xD4, 0xAF, 0xA1, 0xC3, 0x01, 0x64,
		0x95, 0x4E, 0x48, 0x9F, 0xF4, 0x35, 0x78, 0x95, 0x7A, 0x39, 0xD6, 0x6A,
		0xA0, 0x6D, 0x40, 0xE8, 0x4F, 0xA8, 0xEF, 0x11, 0x1D, 0xF3, 0x1B, 0x3F,
		0x3F, 0x07, 0xDD, 0x6F, 0x5B, 0x19, 0x30, 0x19, 0xFB, 0xEF, 0x0E, 0x37,
		0xF0, 0x0E, 0xCD, 0x16, 0x49, 0xFE, 0x53, 0x47, 0x13, 0x1A, 0xBD, 0xA4,
		0xF1, 0x40, 0x19, 0x60, 0x0E, 0xED, 0x68, 0x09, 0x06, 0x5F, 0x4D, 0xCF,
		0x3D, 0x1A, 0xFE, 0x20, 0x77, 0xE4, 0xD9, 0xDA, 0xF9, 0xA4, 0x2B, 0x76,
		0x1C, 0x71, 0xDB, 0x00, 0xBC, 0xFD, 0xC, 0x6C, 0xA5, 0x47, 0xF7, 0xF6,
		0x00, 0x79, 0x4A, 0x11}
	if v >= 0 {
		if v > 0x7FFF {
			v %= 0x7FFF
		}
	} else {
		v = 0
	}
	return key[(v*v+80923)%256]
}

func convert(in string) bool {
	rindex:=strings.LastIndex(in,".")
	name:=in[:rindex]
	e:=in[rindex+1:]
	ext:=""
	if e=="qmcflac" || e=="mflac"{
		ext="flac"
	} else if e=="qmc0" || e=="qmc3"{
		ext="mp3"
	}
	fin,err:=os.Open(in)
	if err!=nil{
		log.Fatal("cannot open "+in)
		return false
	}
	fout,err:=os.Create(name+"."+ext)
	if err!=nil{
		log.Fatal("cannot create new file.")
		return false
	}
	defer fin.Close()
	defer fout.Close()

	stat,_:=fin.Stat()
	buf:=make([]byte,stat.Size())
	fin.Read(buf)
	encrypt(0,buf,len(buf))
	fout.Write(buf)

	return true
}