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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
Copyright (C) 1991-2002, The Numerical ALgorithms Group Ltd.
All rights reserved.
Copyright (C) 2007-2008, Gabriel Dos Reis.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
- Neither the name of The Numerical ALgorithms Group Ltd. nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#define _MSORT3D_C
#include "axiom-c-macros.h"
/*****************************************************
* Mergesort routine *
* *
* This file depends on the file msort.h. There, a *
* data type called linkElement is defined. It is *
* used here and is the main structure being sorted *
* here. You can sort any linked structure, under *
* any name - so long as it has a next field (see *
* below). The define statement, below, renames *
* linkElement to linkThing. All you need to do *
* is change the define statement to rename *
* your structure to linkThing. The first argument *
* you pass to the sort routine is a pointer to *
* the unsorted list. The function returns with *
* that same pointer pointing to a sorted list. *
* *
* Usage: *
* linkElement *msort(p,min,max,compare) *
* linkElement *L; *
* int min,max; *
* int (*compare)(); *
* *
* e.g. *
* msort(L,0,N,compare); *
* *
* where *
* L is the list of things to be sorted, *
* it is expected to be a linked list *
* where the following element is pointed *
* to by a field called "next" *
* 0 is the index of the first element *
* (since this routine is called recursively, *
* this field is kept for clarity; it will *
* always be zero at top level) *
* N the number of elements in the list *
* minus one *
* compare(X,Y) is a comparison function that *
* returns a -1 if X is less than Y *
* 0 if X is the same as Y *
* and 1 if X is greater than Y *
* *
*****************************************************/
#include "header.h"
#include "all_3d.H1"
#define linkThing poly
/**********************
* merge(p,q,compare) *
**********************/
linkThing *
#ifdef _NO_PROTO
merge(p,q,compare)
linkThing *p,*q;
int (*compare)();
#else
merge(linkThing *p, linkThing *q,int (*compare)(linkThing *, linkThing *))
#endif
{
linkThing *returnVal,*current,*pN,*qN;
/* return if only one item - take out when insert sort implemented */
if (!p) return(q); else if (!q) return(p);
/* set up the head of the list (first element) */
if (compare(p,q) <= 0) {
returnVal = current = p;
pN = p->next;
qN = q;
} else {
returnVal = current = q;
pN = p;
qN = q->next;
}
/* merge the two lists */
while ((pN != NULL) && (qN != NULL)) {
if (compare(pN,qN) <= 0) { /* pN <= qN */
current->next = pN;
current = pN;
pN = pN->next;
} else {
current->next = qN;
current = qN;
qN = qN->next;
}
}
/* tag on the tail end */
if (pN == NULL) current->next = qN;
else current->next = pN;
return(returnVal);
} /* merge() */
/*********************************
* msort: the top level function *
*********************************/
linkThing *
#ifdef _NO_PROTO
msort(p,min,max,compare)
linkThing *p;
int min,max;
int (*compare)();
#else
msort(linkThing *p,int min,int max,int (*compare)(linkThing *, linkThing *))
#endif
{
int mid;
int i;
linkThing *q,*temp,*xxx;
if (min == max) return p;
else {
mid = (min + max - 1)/2;
/* e.g. [min,max] = [1,6] => mid=3 => q points to 4th */
for (i=min,q=p; i<mid; i++,q=q->next);
temp = q->next;
q->next = 0;
xxx = merge(msort(p,min,mid,compare),
msort(temp,mid+1,max,compare), compare);
return(xxx);
}
} /* msort() */
|
