1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <mach.h>
include "../qpex.h"
# QP_RLMERGE -- Merge (AND) two range lists. Only ranges which are
# common to both range lists are output. The number of ranges in the
# output range list is returned as the function value.
int procedure qp_rlmerge$t (os,oe,olen, xs,xe,nx, ys,ye,ny)
pointer os, oe #U output range list
int olen #U allocated length of OS, OE arrays
PIXEL xs[ARB], xe[ARB] #I range list to be merged with
int nx #I number of ranges in X list
PIXEL ys[ARB], ye[ARB] #I range list to be merged with X
int ny #I number of ranges in Y list
PIXEL o1, o2
int nx_out, xi, yi, i
PIXEL qp_minval$t(), qp_maxval$t()
bool qp_lessthan$t()
errchk realloc
begin
nx_out = 0
if (nx <= 0 || ny <= 0)
return (0)
xi = 1
yi = 1
do i = 1, ARB {
# Find a pair of ranges which intersect.
repeat {
if (qp_lessthan$t (xe[xi], ys[yi])) {
if (xi >= nx)
return (nx_out)
else
xi = xi + 1
} else if (qp_lessthan$t (ye[yi], xs[xi])) {
if (yi >= ny)
return (nx_out)
else
yi = yi + 1
} else
break
}
# Compute the intersection.
o1 = qp_maxval$t (xs[xi], ys[yi])
o2 = qp_minval$t (xe[xi], ye[yi])
# Output the range.
if (nx_out + 1 > olen) {
olen = max (DEF_XLEN, olen * 2)
call realloc (os, olen, TY_PIXEL)
call realloc (oe, olen, TY_PIXEL)
}
Mem$t[os+nx_out] = o1
Mem$t[oe+nx_out] = o2
nx_out = nx_out + 1
# Advance to the next range.
if (xi < nx && qp_lessthan$t (xe[xi], ye[yi]))
xi = xi + 1
else if (yi < ny)
yi = yi + 1
else
break
}
return (nx_out)
end
# QP_MINVAL -- Return the lesser of two values, where either value can
# be an open range.
PIXEL procedure qp_minval$t (x, y)
PIXEL x #I first value
PIXEL y #I second value
bool qp_lessthan$t()
begin
if (qp_lessthan$t (x, y))
return (x)
else
return (y)
end
# QP_MAXVAL -- Return the greater of two values, where either value can
# be an open range.
PIXEL procedure qp_maxval$t (x, y)
PIXEL x #I first value
PIXEL y #I second value
bool qp_lessthan$t()
begin
if (qp_lessthan$t (x, y))
return (y)
else
return (x)
end
# QP_LESSTHAN -- Test if X is less than Y, where X and Y can be open
# range values.
bool procedure qp_lessthan$t (x, y)
PIXEL x #I first value
PIXEL y #I second value
begin
if (IS_LEFT$T(x))
return (!IS_LEFT$T(y))
else if (IS_RIGHT$T(x))
return (false)
else if (IS_LEFT$T(y))
return (false)
else if (IS_RIGHT$T(y))
return (true)
else
return (x < y)
end
|
