#!/bin/bash

src=$1
dest=_$1

mkdir $dest

#determine number of sections from header
count_bytes=`hexdump -n 4 -s $((0x80)) -e '4/1 "%02x"' $src | tac -rs ..`
declare -i count_int="0x$count_bytes"

dd if=$src of=$dest/0-header bs=1 count=$((0x400))

#dump each section header and payload seperately
for i in `seq 1 $count_int`; do
 declare -i h="$((0xc0))+($i-1)*$((0x40))"
 type=`hexdump -n 1 -s $h -e '"%u"' $src`
 offset=`hexdump -n 4 -s $(($h+4)) -e '4/1 "%02x"' $src | tac -rs ..`
 len=`hexdump -n 4 -s $(($h+12)) -e '4/1 "%02x"' $src | tac -rs ..`
 packed=`hexdump -n 1 -s $(($h+1)) -e '"%u"' $src`
 ubi=`hexdump -n 1 -s $(($h+2)) -e '"%u"' $src`

 dd if=$src of=$dest/$i-header bs=1 skip=$((0x$offset)) count=$((0x40))
 dd if=$src of=$dest/$i-body ibs=1 skip=$((0x$offset+0x40)) obs=$((0x1000)) count=$((0x$len-0x40))

 if [[ "$packed" == "1" ]]; then
  payload="$dest/$i-body.unpacked"
  uncompressed_size_bytes=`hexdump -n 4 -e '4/1 "%02x"' $dest/$i-body`
  declare -i uncompressed_size="0x$uncompressed_size_bytes"

  dd if=$dest/$i-body bs=4096 skip=4 iflag=skip_bytes | zlib-flate -uncompress > $dest/$i-body.unpacked

  size=$(stat -c%s $dest/$i-body.unpacked)

  if [[ "$size" == "$uncompressed_size" ]]; then
    echo "uncompressed OK"
  else
    echo "uncompression FAILED"
  fi
 else
  payload="$dest/$i-body"
 fi

 if [[ "$ubi" == "1" ]]; then
   sudo ubireader_extract_files -k $payload -o $dest/ubifs-$i
 fi
done