package main
import (
iou "0dev.org/ioutil"
predictor "0dev.org/predictor"
"fmt"
"io"
"os"
)
func main() {
var code int
switch {
case len(os.Args) == 1:
code = compress(os.Stdout, os.Stdin)
case len(os.Args) == 2 && os.Args[1] == "-d":
code = decompress(os.Stdout, os.Stdin)
default:
fmt.Fprintln(os.Stdout, "Usage: pdc [-d]")
}
os.Exit(code)
}
// Compress the data from the given io.Reader and write it to the given io.Writer
// I/O is buffered for better performance
func compress(output io.Writer, input io.Reader) int {
var (
err error
buffer io.Writer = iou.SizedWriter(output, 4096)
compressor io.Writer = predictor.Compressor(buffer)
)
_, err = io.Copy(compressor, input)
if err != nil {
fmt.Fprintln(os.Stderr, "Error while compressing.\n", err)
return 1
}
// Flush the compressor
_, err = compressor.Write(nil)
if err != nil {
fmt.Fprintln(os.Stderr, "Error while flushing compresssor buffer.\n", err)
return 1
}
// Flush the buffer
_, err = buffer.Write(nil)
if err != nil {
fmt.Fprintln(os.Stderr, "Error while flushing output buffer.\n", err)
return 1
}
return 0
}
// Decompress the data from the given io.Reader and write it to the given io.Writer
// I/O is buffered for better performance
func decompress(output io.Writer, input io.Reader) int {
var (
err error
buffer io.Writer = iou.SizedWriter(output, 4096)
decompressor io.Reader = predictor.Decompressor(iou.SizedReader(input, 4096))
)
_, err = io.Copy(buffer, decompressor)
if err != nil {
fmt.Fprintln(os.Stderr, "Error while decompressing.\n", err)
return 1
}
// Flush the buffer
_, err = buffer.Write(nil)
if err != nil {
fmt.Fprintln(os.Stderr, "Error while flushing output buffer.\n", err)
return 1
}
return 0
}