#!/bin/bash

size=$(stat --format="%s" $1)

test $size -gt 0 || exit 0

printf "0: 1173 %.6x" $size | xxd -r -g0

if [[ "$OSTYPE" == "linux-gnu"* ]]; then
  # use supplied gzip 1.2.4 for Linux
  gzipbin="tools/gzip"
else
  # use system gzip on other systems
  # NOTE: this might result in a non-matching file, but we don't really care
  gzipbin="gzip -f"
fi

$gzipbin -c --no-name --best $1 | head --bytes=-8 | tail --bytes=+11