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package main
import (
fib "0dev.org/encoding/fibonacci"
mtf "0dev.org/encoding/mtf"
iou "0dev.org/ioutil"
"flag"
"fmt"
"io"
"os"
)
func main() {
d := flag.Bool("d", false, "Use to toggle decode mode")
d := flag.Bool("d", false, "Toggle decode mode.")
flag.Parse()
var code int
if *d {
code = decode(os.Stdout, os.Stdin)
} else {
var (
input io.Reader = iou.SizedReader(os.Stdin, 4096)
output io.Writer = iou.SizedWriter(os.Stdout, 4096)
code int
code = encode(os.Stdout, os.Stdin)
}
os.Exit(code)
}
)
// Exit handler
defer func() {
os.Exit(code)
}()
// Transforms the data according to the move-to-front algorithm
// I/O is buffered for better performance
func encode(output io.Writer, input io.Reader) int {
var (
err error
encoder io.Reader = mtf.Encoder(iou.SizedReader(input, 4096))
)
_, err = io.Copy(output, encoder)
// Flush the output buffer
defer output.Write(nil)
if err != nil {
fmt.Fprintln(os.Stderr, "Error while encoding.\n", err)
return 1
}
return 0
}
if *d {
input = mtf.Decoder(fib.Decoder(input))
} else {
input = mtf.Encoder(input)
// Encode output as fibonacci integers
output = fib.Encoder(output)
defer output.Write(nil)
}
// Reverses MTF`ed data and writes back the original bytes
// I/O is buffered for better performance
func decode(output io.Writer, input io.Reader) int {
var (
err error
decoder io.Reader = mtf.Decoder(iou.SizedReader(input, 4096))
)
_, err = io.Copy(output, decoder)
if _, err := io.Copy(output, input); err != nil {
if err != nil {
fmt.Fprintln(os.Stderr, "Error while decoding.\n", err)
return 1
os.Stderr.WriteString("Error while transforming data.\n" + err.Error())
code = 1
}
return 0
}
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