Extract .iraw files that some Flash videoconferencing systems use

extractiraw.go

package main

import (
	"log"
	"os"
	"io/ioutil"
	"encoding/binary"
	"net/http"
	"mime"
	"fmt"
)

func main() {
	fn := "/path/to/file.ppt.iraw"
	outdir := fn + ".parts"
	
	err := os.MkdirAll(outdir, 0777)
	if err != nil {
		log.Fatal(err)
	}
	
	data, err := ioutil.ReadFile(fn)
	if err != nil {
		log.Fatal(err)
	}
	
	o := 0

	n := int(binary.BigEndian.Uint32(data[o:o+4]))
	o += 4
	log.Printf("n = %d, len(data) = %d", n, len(data))
	
	for i := 0; i < n; i++ {
		size := int(binary.BigEndian.Uint32(data[o:o+4]))
		o += 4
		
		item := data[o:o+size]
		o += size

		ctype := http.DetectContentType(item)
		var ext string
		if ctype != "" {
			exts, err := mime.ExtensionsByType(ctype)
			if err != nil {
				log.Fatal(err)
			}
			if len(exts) > 0 {
				ext = exts[0]
			}
		}
		if ext == "" {
			ext = ".bin"
		}
		log.Printf("#%03d len = %d, ctype = %q, ext = %q", i+1, size, ctype, ext)
		
		ofn := outdir + "/" + fmt.Sprintf("part%04d%s", i+1, ext)
		err := ioutil.WriteFile(ofn, item, 0666)
		if err != nil {
			log.Fatal(err)
		}		
	}

	log.Printf("offset = %d, len(data) = %d", o, len(data))
}