shell

#!/bin/bash
# Utilities for HID++ accesses.
#
# Author: Peter Wu <lekensteyn@gmail.com>

hidw() {
	local hiddev arg bytes fillchar length oIFS actualArgs
	hiddev=$1; shift
	bytes=()

	case $hiddev in
	''|-h|--help|-?)
		cat <<HELP
Usage: hidw /dev/hidrawX [data]

data are hexadecimal numbers in the range 0x0-0xff ('0x' prefix is
optional). Missing bytes for HID++ reports (0x10 and 0x11) and DJ
reports (0x20 and 0x21) will be padded by zeroes unless you end with ..
as in the following (non-meaningful) example:

    hidw /dev/hidraw0 10 ff 81  ff..

In this case, the message is padded with '0xff'.

The data can also be interleaved with chars by starting an argument
with a underscore (_). For example, "_foo" is equivalent to "66 6f 6f".
A colon can also be used as separator, the previous hidw example is
equivalent to:

    hidw /dev/hidraw0 10:ff 81:ff..

This function does not show replies, use the 'read-dev-usbmon' program
instead.
HELP
		return 1 ;;
	esac

	if [ ! -c "$hiddev" ]; then
		echo "$hiddev: not a block special"
		return 1
	fi

	# Support ":" as separator, but ignore string arguments (_...).
	actualArgs=()
	for arg; do
		if [[ $arg != _* ]] && [[ $arg == *:* ]]; then
			# Strip leading+trailing such that "11:02: 83 01" is still valid.
			arg="${arg##:}"
			arg="${arg%%:}"
			oIFS="$IFS"; IFS=:; actualArgs+=( $arg ); IFS="$oIFS"
		else
			actualArgs+=( "$arg" )
		fi
	done
	set -- "${actualArgs[@]}"

	for arg; do
		# clear the fill char, makes only sense as last argument
		fillchar=
		if [[ $arg =~ ^(0[xX])?[0-9a-fA-F]{1,2}(\.\.)?$ ]]; then
			byte=${arg#0[Xx]}
			byte=${byte%..}
			[ ${#byte} = 2 ] || byte=0$byte
			bytes+=($byte)

			# extend with last byte
			[[ $arg != *.. ]] || fillchar=$byte
		elif [[ $arg =~ ^_ ]]; then
			# Literal string
			bytes+=( $(echo -n "${arg#_}" | xxd -ps | fold -w2) )
		else
			echo "Invalid argument: $arg"
			return 1
		fi
	done

	case ${bytes[0]} in
	10) length=7 ;;
	11) length=20 ;;
	20) length=15 ;;
	21) length=32 ;;
	*) echo "Unknown report type ${bytes[0]}, not padding " ;;
	esac

	if [ $length ]; then
		[ -n "$fillchar" ] || fillchar=00
		while [ ${#bytes[@]} -lt $length ]; do
			bytes+=($fillchar)
		done

		if [ ${#bytes[@]} -gt $length ]; then
			echo "Too many arguments: ${#bytes[@]} > $length"
			return 1
		fi
	fi

	echo "${bytes[@]}" | xxd -ps -r > "$hiddev"
}

_hidpp_main() {
	local cmd
	local cmds=(hidw)
	cmd=$1; shift

	for c in "${cmds[@]}"; do
		if [[ $cmd == $c ]]; then
			$cmd "$@"
			return
		fi
	done

	case $cmd in
	''|-h|--help|-?)
		cat <<HELP
Usage: $0 command [command args]

Available commands:
  ${cmds[*]}

You can also source this file to export those functions.
HELP
		;;
	*)
		echo "Unknown command, invoke with no arguments for help."
		;;
	esac

}

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
	_hidpp_main "$@"
fi

# vim: set syntax=sh: