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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <plset.h>
include <plio.h>
# PL_R2L -- Convert a range list to a line list. The length of the output
# line list is returned as the function value.
int procedure pl_r2ll (rl_src, xs, ll_dst, npix)
long rl_src[3,ARB] #I input range list
int xs #I starting pixel index in range list
short ll_dst[ARB] #O destination line list
int npix #I number of pixels to convert
long hi, pv
int last, xe, x1, x2, iz, op, np, nz, nr, dv, v, i
define done_ 91
begin
# No input pixels?
nr = RL_LEN(rl_src)
if (npix <= 0 || nr <= 0)
return (0)
# Initialize the linelist header.
LL_VERSION(ll_dst) = LL_CURVERSION
LL_HDRLEN(ll_dst) = LL_CURHDRLEN
LL_NREFS(ll_dst) = 0
LL_SETBLEN(ll_dst,0)
xe = xs + npix - 1
op = LL_CURHDRLEN + 1
iz = xs
hi = 1
# Process the array of range lists.
do i = RL_FIRST, nr + 1 {
if (i <= nr) {
# Load next range.
x1 = rl_src[1,i]
np = rl_src[2,i]
pv = rl_src[3,i]
x2 = x1 + np - 1
last = x2
# Get an inbounds range.
if (x1 > xe)
break
else if (xs > x2)
next
else if (x1 < xs)
x1 = xs
else if (x2 > xe)
x2 = xe
# Go again if nothing inbounds.
nz = x1 - iz
np = x2 - x1 + 1
if (np <= 0)
next
} else if (iz < xe) {
# At end of input range list, but need to output a ZN.
nz = xe - iz + 1
np = 0
pv = 0
} else
break
# Encode an instruction to regenerate the current range I0-IP
# of N data values of nonzero level PV. In the most complex case
# we must update the high value and output a range of zeros,
# followed by a range of NP high values. If NP is 1, we can
# probably use a PN or [ID]S instruction to save space.
# Change the high value?
if (pv > 0) {
dv = pv - hi
if (dv != 0) {
# Output IH or DH instruction?
hi = pv
if (abs(dv) > I_DATAMAX) {
ll_dst[op] = M_SH + and (int(pv), I_DATAMAX)
op = op + 1
ll_dst[op] = pv / I_SHIFT
op = op + 1
} else {
if (dv < 0)
ll_dst[op] = M_DH + (-dv)
else
ll_dst[op] = M_IH + dv
op = op + 1
# Convert to IS or DS if range is a single pixel.
if (np == 1 && nz == 0) {
v = ll_dst[op-1]
ll_dst[op-1] = or (v, M_MOVE)
goto done_
}
}
}
}
# Output range of zeros to catch up to current range?
if (nz > 0) {
# Output the ZN instruction.
for (; nz > 0; nz = nz - (I_DATAMAX-1)) {
ll_dst[op] = M_ZN + min(I_DATAMAX-1,nz)
op = op + 1
}
# Convert to PN if range is a single pixel.
if (np == 1 && pv > 0 && x2 == last) {
ll_dst[op-1] = ll_dst[op-1] + M_PN + 1
goto done_
}
}
# The only thing left is the HN instruction if we get here.
for (; np > 0; np = np - I_DATAMAX) {
ll_dst[op] = M_HN + min(I_DATAMAX,np)
op = op + 1
}
done_
iz = x2 + 1
}
LL_SETLEN(ll_dst, op - 1)
return (op - 1)
end
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