ziphash.go

package main

import (
	"archive/zip"
	"crypto/sha1"
	"fmt"
	"os"
)

func main() {
	for _, fn := range os.Args[1:] {
		zh, err := ziphash(fn)
		if err != nil {
			panic(err)
		}
		fmt.Println(zh, fn)
	}
}

// ziphash is a fast hashing function for zip files based on the stored CRC32s.
func ziphash(filename string) (string, error) {
	z, err := zip.OpenReader(filename)
	if err != nil {
		return "", err
	}
	defer z.Close()

	sh := sha1.New()
	for _, zf := range z.File {
		sh.Write([]byte(fmt.Sprint(zf.CRC32, zf.UncompressedSize64)))
	}
	return fmt.Sprintf("%x", sh.Sum(nil)), nil
}

zipmeta.go

package main

import (
	"archive/zip"
	"fmt"
	"os"
)

func main() {
	zr, err := zip.OpenReader(os.Args[1])
	if err != nil {
		panic(err)
	}
	defer zr.Close()

	for _, zf := range zr.File {
		fmt.Printf("%+v\n", zf)
	}
}