1 /* drmsl.c -- Skip list test
2 * Created: Mon May 10 09:28:13 1999 by faith@precisioninsight.com
3 *
4 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the next
15 * paragraph) shall be included in all copies or substantial portions of the
16 * Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
22 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
24 * DEALINGS IN THE SOFTWARE.
25 *
26 * Authors: Rickard E. (Rik) Faith <faith@valinux.com>
27 *
28 * DESCRIPTION
29 *
30 * This file contains a straightforward skip list implementation.n
31 *
32 * FUTURE ENHANCEMENTS
33 *
34 * REFERENCES
35 *
36 * [Pugh90] William Pugh. Skip Lists: A Probabilistic Alternative to
37 * Balanced Trees. CACM 33(6), June 1990, pp. 668-676.
38 *
39 */
40
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <sys/time.h>
44
45 #include "xf86drm.h"
46
print(void * list)47 static void print(void* list)
48 {
49 unsigned long key;
50 void *value;
51
52 if (drmSLFirst(list, &key, &value)) {
53 do {
54 printf("key = %5lu, value = %p\n", key, value);
55 } while (drmSLNext(list, &key, &value));
56 }
57 }
58
do_time(int size,int iter)59 static double do_time(int size, int iter)
60 {
61 void *list;
62 int i, j;
63 unsigned long keys[1000000];
64 unsigned long previous;
65 unsigned long key;
66 void *value;
67 struct timeval start, stop;
68 double usec;
69 void *ranstate;
70
71 list = drmSLCreate();
72 ranstate = drmRandomCreate(12345);
73
74 for (i = 0; i < size; i++) {
75 keys[i] = drmRandom(ranstate);
76 drmSLInsert(list, keys[i], NULL);
77 }
78
79 previous = 0;
80 if (drmSLFirst(list, &key, &value)) {
81 do {
82 if (key <= previous) {
83 printf( "%lu !< %lu\n", previous, key);
84 }
85 previous = key;
86 } while (drmSLNext(list, &key, &value));
87 }
88
89 gettimeofday(&start, NULL);
90 for (j = 0; j < iter; j++) {
91 for (i = 0; i < size; i++) {
92 if (drmSLLookup(list, keys[i], &value))
93 printf("Error %lu %d\n", keys[i], i);
94 }
95 }
96 gettimeofday(&stop, NULL);
97
98 usec = (double)(stop.tv_sec * 1000000 + stop.tv_usec
99 - start.tv_sec * 1000000 - start.tv_usec) / (size * iter);
100
101 printf("%0.2f microseconds for list length %d\n", usec, size);
102
103 drmRandomDouble(ranstate);
104 drmSLDestroy(list);
105
106 return usec;
107 }
108
print_neighbors(void * list,unsigned long key,unsigned long expected_prev,unsigned long expected_next)109 static void print_neighbors(void *list, unsigned long key,
110 unsigned long expected_prev,
111 unsigned long expected_next)
112 {
113 unsigned long prev_key = 0;
114 unsigned long next_key = 0;
115 void *prev_value;
116 void *next_value;
117 int retval;
118
119 retval = drmSLLookupNeighbors(list, key,
120 &prev_key, &prev_value,
121 &next_key, &next_value);
122 printf("Neighbors of %5lu: %d %5lu %5lu\n",
123 key, retval, prev_key, next_key);
124 if (prev_key != expected_prev) {
125 fprintf(stderr, "Unexpected neighbor: %5lu. Expected: %5lu\n",
126 prev_key, expected_prev);
127 exit(1);
128 }
129 if (next_key != expected_next) {
130 fprintf(stderr, "Unexpected neighbor: %5lu. Expected: %5lu\n",
131 next_key, expected_next);
132 exit(1);
133 }
134 }
135
main(void)136 int main(void)
137 {
138 void* list;
139 double usec, usec2, usec3, usec4;
140
141 list = drmSLCreate();
142 printf( "list at %p\n", list);
143
144 print(list);
145 printf("\n==============================\n\n");
146
147 drmSLInsert(list, 123, NULL);
148 drmSLInsert(list, 213, NULL);
149 drmSLInsert(list, 50, NULL);
150 print(list);
151 printf("\n==============================\n\n");
152
153 print_neighbors(list, 0, 0, 50);
154 print_neighbors(list, 50, 0, 50);
155 print_neighbors(list, 51, 50, 123);
156 print_neighbors(list, 123, 50, 123);
157 print_neighbors(list, 200, 123, 213);
158 print_neighbors(list, 213, 123, 213);
159 print_neighbors(list, 256, 213, 256);
160 printf("\n==============================\n\n");
161
162 drmSLDelete(list, 50);
163 print(list);
164 printf("\n==============================\n\n");
165
166 drmSLDump(list);
167 drmSLDestroy(list);
168 printf("\n==============================\n\n");
169
170 usec = do_time(100, 10000);
171 usec2 = do_time(1000, 500);
172 printf("Table size increased by %0.2f, search time increased by %0.2f\n",
173 1000.0/100.0, usec2 / usec);
174
175 usec3 = do_time(10000, 50);
176 printf("Table size increased by %0.2f, search time increased by %0.2f\n",
177 10000.0/100.0, usec3 / usec);
178
179 usec4 = do_time(100000, 4);
180 printf("Table size increased by %0.2f, search time increased by %0.2f\n",
181 100000.0/100.0, usec4 / usec);
182
183 return 0;
184 }
185