-
-
Notifications
You must be signed in to change notification settings - Fork 121
/
listsort.c
231 lines (200 loc) · 5.52 KB
/
listsort.c
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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
#include <stdlib.h>
#include <stdio.h>
#include "listsort.h"
/* from http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.c */
/*
* This file is copyright 2001 Simon Tatham.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
static double cmp(JsonNode * a, JsonNode * b)
{
JsonNode *ta = json_find_member(a, "tst");
JsonNode *tb = json_find_member(b, "tst");
//printf("a=%lf, b=%lf\n", ta->number_, tb->number_);
/* user may have chosen fields without tst */
if (!ta || !tb)
return (0.0);
return ta->number_ - tb->number_;
}
/*
* This is the actual sort function. Notice that it returns the new head of
* the list. (It has to, because the head will not generally be the same
* element after the sort.) So unlike sorting an array, where you can do
*
* sort(myarray);
*
* you now have to do
*
* list = listsort(mylist);
*/
JsonNode *listsort(JsonNode * list, int is_circular, int is_double)
{
JsonNode *p, *q, *e, *tail, *oldhead;
int insize, nmerges, psize, qsize, i;
/*
* Silly special case: if `list' was passed in as NULL, return NULL
* immediately.
*/
if (!list)
return NULL;
insize = 1;
while (1) {
p = list;
oldhead = list; /* only used for circular linkage */
list = NULL;
tail = NULL;
nmerges = 0; /* count number of merges we do in this pass */
while (p) {
nmerges++; /* there exists a merge to be done */
/* step `insize' places along from p */
q = p;
psize = 0;
for (i = 0; i < insize; i++) {
psize++;
if (is_circular)
q = (q->next == oldhead ? NULL : q->next);
else
q = q->next;
if (!q)
break;
}
/*
* if q hasn't fallen off end, we have two lists to
* merge
*/
qsize = insize;
/* now we have two lists; merge them */
while (psize > 0 || (qsize > 0 && q)) {
/*
* decide whether next element of merge comes
* from p or q
*/
if (psize == 0) {
/* p is empty; e must come from q. */
e = q;
q = q->next;
qsize--;
if (is_circular && q == oldhead)
q = NULL;
} else if (qsize == 0 || !q) {
/* q is empty; e must come from p. */
e = p;
p = p->next;
psize--;
if (is_circular && p == oldhead)
p = NULL;
} else if (cmp(p, q) <= 0) {
/*
* First element of p is lower (or
* same); e must come from p.
*/
e = p;
p = p->next;
psize--;
if (is_circular && p == oldhead)
p = NULL;
} else {
/*
* First element of q is lower; e
* must come from q.
*/
e = q;
q = q->next;
qsize--;
if (is_circular && q == oldhead)
q = NULL;
}
/* add the next element to the merged list */
if (tail) {
tail->next = e;
} else {
list = e;
}
if (is_double) {
/*
* Maintain reverse pointers in a
* doubly linked list.
*/
e->prev = tail;
}
tail = e;
}
/*
* now p has stepped `insize' places along, and q has
* too
*/
p = q;
}
if (is_circular) {
tail->next = list;
if (is_double)
list->prev = tail;
} else
tail->next = NULL;
/* If we have done only one merge, we're finished. */
if (nmerges <= 1) /* allow for nmerges==0, the empty
* list case */
return list;
/* Otherwise repeat, merging lists twice the size */
insize *= 2;
}
}
#ifdef TESTING
int main()
{
JsonNode *n, *sorted, *arr = json_mkarray();
JsonNode *o;
o = json_mkobject();
json_append_member(o, "tst", json_mknumber(2));
json_append_member(o, "desc", json_mkstring("dos"));
json_append_element(arr, o);
o = json_mkobject();
json_append_member(o, "tst", json_mknumber(69));
json_append_member(o, "desc", json_mkstring("sixtynine"));
json_append_element(arr, o);
o = json_mkobject();
json_append_member(o, "tst", json_mknumber(14));
json_append_member(o, "desc", json_mkstring("fourteen"));
json_append_element(arr, o);
o = json_mkobject();
json_append_member(o, "tst", json_mknumber(7));
json_append_member(o, "desc", json_mkstring("seven"));
json_append_element(arr, o);
json_foreach(n, arr) {
JsonNode *e = json_find_member(n, "tst");
JsonNode *d = json_find_member(n, "desc");
printf("%lf - %s\n", e->number_, d->string_);
}
listsort(NULL, 0, 0);
sorted = listsort(json_first_child(arr), 0, 0);
sorted = sorted->parent;
printf("------- %s\n", (sorted == arr) ? "SAME" : "different");
json_foreach(n, sorted) {
JsonNode *e = json_find_member(n, "tst");
JsonNode *d = json_find_member(n, "desc");
printf("%lf - %s\n", e->number_, d->string_);
}
json_delete(arr);
return 0;
}
#endif