Compress a folder into a hopefully working character pack for SRB2kart

compress.go

package main

import (
	"archive/zip"
	"flag"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
)

func main() {
	inpath := flag.String("d", "", "Input folder")
	outpath := flag.String("f", "", "Output file")
	flag.Parse()

	file, err := os.Create(*outpath)
	checkErr(err)
	w := zip.NewWriter(file)

	allfiles := []string{}
	skins := make(map[string]bool)
	filepath.Walk(*inpath, func(path string, info os.FileInfo, err error) error {
		checkErr(err)
		relpath, err := filepath.Rel(*inpath, path)
		checkErr(err)
		zippath := strings.Replace(relpath, string(os.PathSeparator), "/", -1)
		if strings.HasSuffix(zippath, "/S_SKIN") {
			skins[zippath] = true
			return nil
		}
		if zippath == "." || info.IsDir() {
			return nil
		}
		allfiles = append(allfiles, zippath)
		return nil
	})

	roots := make(map[string]bool)
	for _, file := range allfiles {
		dir := strings.Replace(filepath.Dir(file), string(os.PathSeparator), "/", -1) + "/"
		// Did we ever get to this dir?
		_, ok := roots[dir]
		if !ok {
			// Create dir
			fmt.Printf(" - %s [DIR]\n", dir)
			w.Create(dir)
			roots[dir] = true
			// Check for S_SKIN
			sskin := dir + "S_SKIN"
			if _, ok := skins[sskin]; ok {
				fmt.Printf("[ SKIN \"%s\" ]\n", filepath.Base(dir))
				fmt.Printf(" - %s\n", sskin)
				checkErr(copyFile(w, filepath.Join(*inpath, sskin), sskin))
			}
		}
		fmt.Printf(" - %s\n", file)
		checkErr(copyFile(w, filepath.Join(*inpath, file), file))
	}

	checkErr(w.Close())
}

func copyFile(w *zip.Writer, path string, target string) error {
	rc, err := os.Open(path)
	if err != nil {
		return err
	}
	fw, err := w.Create(target)
	if err != nil {
		return err
	}
	_, err = io.Copy(fw, rc)
	if err != nil {
		return err
	}
	return rc.Close()
}

func checkErr(err error) {
	if err != nil {
		panic(err)
	}
}