/
main.go
63 lines (54 loc) · 1000 Bytes
/
main.go
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package main
import (
"golang.org/x/xerrors"
"io/ioutil"
"log"
"os"
"rsc.io/qr"
)
func main() {
err := run()
if err != nil {
log.Fatal(err)
}
}
func run() error {
var (
src string
dst string = "qr.png"
argn int = 2 // max number of arguments
)
stat, err := os.Stdin.Stat()
if err != nil {
return err
}
if stat.Mode()&os.ModeCharDevice == 0 {
input, err := ioutil.ReadAll(os.Stdin)
if err != nil {
return err
}
src = string(input)
argn-- // if the input text exists, "src" argument will be not required.
} else {
if len(os.Args) < 2 {
return xerrors.New("The source text must be given!")
}
src = os.Args[1]
}
if len(src) == 0 {
return xerrors.New("The source text must be given!")
}
switch len(os.Args) {
case argn:
break
case argn + 1:
dst = os.Args[2]
default:
return xerrors.New("Invalid arguments!")
}
code, err := qr.Encode(src, qr.M)
if err != nil {
return err
}
return ioutil.WriteFile(dst, code.PNG(), 0644)
}