CD-type chd extractor (V5 only, supports clones)

chdextract

#!/usr/bin/env bash

declare -A parents
function getparents {
	for i in *.chd; do
		if [[ "$(xxd -ps -s 104 -l 20 "$i")" = "0000000000000000000000000000000000000000" ]]; then 
			parents["$(xxd -ps -s 84 -l 20 "$i")"]="$i"
		fi
	done
}

for chdFile in *.chd; do
	[[ $chdFile = '*.chd' ]] && echo "No chd files exist in the current directory" && break
	# If first track is CHGD, extraction type should be gdi
	parenthash=$(xxd -ps -s 104 -l 20 "$chdFile")
	[[ $(xxd -ps -s 124 -l 4 "$chdFile") = "43484744" ]] && ext=".gdi" || ext=".cue"
	game="${chdFile%.chd}"
	echo "Extracting $game..."
	if [[ $parenthash = "0000000000000000000000000000000000000000" ]]; then
		# No parent, thus can be extracted directly
		chdman extractcd -i "$chdFile" -o "$game$ext"
	else
		# Has parent, run getparents if the parents array is empty
		[[ ${#x[@]} -eq 0 ]] && getparents
		chdver=$(xxd -ps -s 12 -l 4 "$chdFile")
		[[ chdver -ne 5 ]] && echo "Currently only CHD v5 is supported" && continue
		# Bail if parent wasn't located
		if [[ ${parents[$parenthash]} ]]; then
			chdman extractcd -i "$chdFile" -ip "${parents[$parenthash]}" -o "$game$ext"
		else
			echo "**Cannot extract, parent was not found**"
		fi
	fi
	echo
done

echo "All done."