fds.inc.sh

#!/usr/bin/env bash
. include arrays

SHOWWRITE=0
SHOWWRITEERROR=1
MIN_FD=12
LAST_FD=$MIN_FD
export FD_LIST
open() {
	local argc=$#
	local filename=$1
	local mode=$2
	# local fd=<( true )		# allocate ourselves a temporary fd 
	local pipe
	# echo "$fd"

	# cat < $fd > /dev/null	# use the fd, so it is open for reuse
	# fd=${fd##/*/}				# trim the non-numeric stuff (/dev/fd/64)
	while [ -a /proc/self/fd/$LAST_FD ]
	do
		(( LAST_FD++ ))
	done
	fd=$LAST_FD
	# echo "open: fd: $fd" >&2

	(( !argc ))     && eval "exec $fd<>/dev/null"		# no arguments, just allocate fd
	(( argc == 1 )) && eval "exec $fd<&\"$filename\""	# no mode, assume read
	(( argc == 2 )) && case mode in
								r ) pipe='<&' 
									;;
								w ) pipe='>&' 
									;;
								* ) pipe='<>'
							 esac && 
							 eval "exec $fd$pipe\"$filename\""

	el=$?
   # exec 11<>/dev/tcp/roomlock.stinkyrabbit.com/45678
	# sleep 1
	# echo >& 11
	# cat <& 11
	FD=$fd					# "export" FD into global scope 
	FD_LIST[$fd]="$1"
	# ls -sal /proc/self/fd
	# lsof -np $$ | grep ${fd}u
	(( el )) && echo "el was $el" >&2
	# lsof -p $$
	return $el				# return errorlevel of exec (hopefully)
}


write() {
	# fd=${1##/*/}				# trim the non-numeric stuff (/dev/fd/64)
	local fd=$1
	shift 

	local writing="$*"
	# writing=${writing%%$'\x0a'}
	writing="$1"
	(( SHOWWRITE )) && echo "Writing '$writing' to $fd ..."
	echo -n "$writing" >&$fd			# must use CR without LF for EOL
	el=$?										# should check for non-zero response indicating non-existant device
	if [ "$el" -ne "0" ]; then
		(( SHOWWRITEERROR )) && echo "ERROR WRITING FD#$fd (${FD_LIST[$fd]})"
		return 1
	fi
	return 0
}

writeline() {
	# Nasty hack
	write "$@" &&
	write "$1" $'\x0a' &&
	return 0
	return 1
}

close() {
	while [ -n "$1" ]; do
		fd=${1##/*/}				# trim the non-numeric stuff (/dev/fd/64)
		eval "exec $fd<&-"
		(( fd == LAST_FD && fd > MIN_FD )) && 
		{
			echo "closed and decremented LAST_FD from $fd" >&2
			(( LAST_FD-- ))
			unset FD_LIST[$fd]
		} ||
		{
			echo "closed fd $fd" >&2
		}
		shift
	done
}

fgets() {
	local fd="$1"
	REPLY=
	# IFS=$'\x0d\x0a' read -t 60 -d $'\x0d' -r < $fd
	pushifs ''
	IFS= read -t 60 -r -u $fd
	el=$?
	REPLY=${REPLY%$'\x0d'}
	popifs
	# echo "$REPLY"
	# printf '%03s,%1s %s\n' ${#REPLY} $el "$REPLY"
	return $el
}


gsm_fgets() {
	local lines=0
	local blanks=0
	local error=0
	local at=0
	local ok=0
	local unknown=0
	local fd=$1
	local line
	# dd if=$fd of=/dev/null bs=1 count=1
	while true 
	do
		setifs ''
		read -t 1 -n 1024 -r -d $'\x0a' -a line < $fd
		el=$?
		setifs
		declare -p line > /dev/stderr
		[ "${#line}" -eq "0" ] &&
			(( blanks++ )) || 
		case ${line[0]} in
			AT* ) (( at++ )) 			# Must be in ECHO mode, this is the same as a new line basically, and we expect to receive this first
				;;
			OK ) (( ok++ ))
				;;
			ERROR ) (( error++ ))
				;;
			* ) (( unknown++ ))
		esac

		(( lines ++ ))

		# (( ok || error )) && break
		echo lines: $lines  at: $at  blanks: $blanks > /dev/stderr
		(( lines > 1 || at || blanks )) || continue
		declare -p line
		return $el
		
	done
}

gsm_read() {
	local -a lines
	local -a line_pos=0
	while line=$( gsm_fgets $FD ); do
		# echo $line
		eval $line
		echo ${line[@]}
		lines[${#lines[*]}]="${line[@]}"
		# lines+=( ${line[@]} )
		case ${line[0]} in
			OK | ERROR ) break
		esac
	done
	declare -p lines
}

fds__test() {
	open /dev/cu.HU*Modem rw
	# lsof -np $$ | grep Modem
	(( LINUX )) && stty -F $FD -inlcr -icrnl -igncr
	(( DARWIN )) && stty -f /dev/cu.HU*Modem 115200 -inlcr -icrnl igncr
	echo -en "AT E1 \r" > $FD
	gsm_read
	close $FD

	# lsof -n -p $$ | grep '6[0-9]u'
}