# PLLSEG.H -- Macros for sequentially reading segments of a line list.
#
#	       pll_init (ll, descriptor)
#      npix = pll_nleft (descriptor)
#      val = pll_getseg (ll, descriptor, npix, value)
#
# pll_init	Initialize descriptor for sequential i/o from the linelist LL.
# pll_nleft	Number of pixels left in the current line segment of constant
#		  value.  Zero is returned at the EOL.
# pll_getseg	Read NPIX pixels from the current segment, advancing to the
#		  next segment automatically when the the current segment is
#		  exhausted.
#
# The descriptor is an integer array, the contents of which are hidden from
# the application using these macros.  This package uses the internal
# procedure PLL_NEXTSEG, which is included in PL package library.

# Range list i/o descriptor.
define	LEN_PLLDES	7
define	ld_nleft	$1[1]
define	ld_value	$1[2]
define	ld_x		$1[3]
define	ld_ip		$1[4]
define	ld_hi		$1[5]
define	ld_next_nleft	$1[6]
define	ld_next_value	$1[7]

# PLL_NLEFT -- Number of pixels left in the current segment.
define	pll_nleft	ld_nleft($1)

## PLL_INIT -- Initialize the linelist descriptor.
#define	(pll_init, {			# $1=ll $2=des
#	# ld_x($2) = 1
#	ld_hi($2) = 1
#	if (LL_OLDFORMAT($1))
#	    ld_ip($2) = OLL_FIRST
#	else
#	    ld_ip($2) = LL_FIRST($1)
#	ld_next_nleft($2) = 0
#	ld_nleft($2) = 0
#	call pll_nextseg ($1, $2)
#})

define	(pll_init, {ld_hi($2)=1;if(LL_OLDFORMAT($1)){ld_ip($2)=OLL_FIRST;}else{ld_ip($2)=LL_FIRST($1);}ld_next_nleft($2)=0;ld_nleft($2)=0;call pll_nextseg($1,$2);})

#
## PLL_GETSEG -- Read pixels from the current segment.
#define	(pll_getseg, {			# $1=ll $2=des $3=npix $4=value
#	$4 = ld_value($2)
#	# ld_x($2) = ld_x($2) + $3
#	ld_nleft($2) = ld_nleft($2) - $3
#	if (ld_nleft($2) <= 0)
#	    if (ld_next_nleft($2) > 0) {
#		ld_nleft($2) = ld_next_nleft($2)
#		ld_value($2) = ld_next_value($2)
#		ld_next_nleft($2) = 0
#	    } else
#		call pll_nextseg ($1, $2)
#})

define	(pll_getseg, {$4=ld_value($2);ld_nleft($2)=ld_nleft($2)-$3;if(ld_nleft($2)<=0){if(ld_next_nleft($2)>0){ld_nleft($2)=ld_next_nleft($2);ld_value($2)=ld_next_value($2);ld_next_nleft($2)=0;}else{call pll_nextseg($1,$2);}}})