#!/bin/bash
# Retrive content size of an lz4 compressed file.
# Compatible only with lz4 files created with --content-size flag
file="$1"
if ! file "$file" | grep LZ4 > /dev/null; then
	printf "%s: Is not recognised as a lz4 file\\n" "$file" >&2
	exit 1
fi
csflag=$(od -An -t x2 -N 1 -j 4 "$file" | xargs)
if [ ! "$csflag" == "006c" ]; then
	printf "%s: No content-size flag\\n" "$file" >&2
	exit 1
fi
printf "%s: " "$file"
od -An -t d -N 8 -j 6 "$file" | awk '{print $1}'