1/*
2 * Copyright 2009 Google Inc.  All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24import java.util.Random;
25import java.math.BigInteger;
26
27public enum ArrayBuilder {
28
29    // These seven are from  Tim's paper (listsort.txt)
30
31    RANDOM_INT {
32        public Object[] build(int len) {
33            Integer[] result = new Integer[len];
34            for (int i = 0; i < len; i++)
35                result[i] = rnd.nextInt();
36            return result;
37        }
38    },
39
40    DESCENDING_INT {
41        public Object[] build(int len) {
42            Integer[] result = new Integer[len];
43            for (int i = 0; i < len; i++)
44                result[i] = len - i;
45            return result;
46        }
47    },
48
49    ASCENDING_INT {
50        public Object[] build(int len) {
51            Integer[] result = new Integer[len];
52            for (int i = 0; i < len; i++)
53                result[i] = i;
54            return result;
55        }
56    },
57
58    ASCENDING_3_RND_EXCH_INT {
59        public Object[] build(int len) {
60            Integer[] result = new Integer[len];
61            for (int i = 0; i < len; i++)
62                result[i] = i;
63            for (int i = 0; i < 3; i++)
64                swap(result, rnd.nextInt(result.length),
65                             rnd.nextInt(result.length));
66            return result;
67        }
68    },
69
70    ASCENDING_10_RND_AT_END_INT {
71        public Object[] build(int len) {
72            Integer[] result = new Integer[len];
73            int endStart = len - 10;
74            for (int i = 0; i < endStart; i++)
75                result[i] = i;
76            for (int i = endStart; i < len; i++)
77                result[i] = rnd.nextInt(endStart + 10);
78            return result;
79        }
80    },
81
82    ALL_EQUAL_INT {
83        public Object[] build(int len) {
84            Integer[] result = new Integer[len];
85            for (int i = 0; i < len; i++)
86                result[i] = 666;
87            return result;
88        }
89    },
90
91    DUPS_GALORE_INT {
92        public Object[] build(int len) {
93            Integer[] result = new Integer[len];
94            for (int i = 0; i < len; i++)
95                result[i] = rnd.nextInt(4);
96            return result;
97        }
98    },
99
100    RANDOM_WITH_DUPS_INT {
101        public Object[] build(int len) {
102            Integer[] result = new Integer[len];
103            for (int i = 0; i < len; i++)
104                result[i] = rnd.nextInt(len);
105            return result;
106        }
107    },
108
109    PSEUDO_ASCENDING_STRING {
110        public String[] build(int len) {
111            String[] result = new String[len];
112            for (int i = 0; i < len; i++)
113                result[i] = Integer.toString(i);
114            return result;
115        }
116    },
117
118    RANDOM_BIGINT {
119        public BigInteger[] build(int len) {
120            BigInteger[] result = new BigInteger[len];
121            for (int i = 0; i < len; i++)
122                result[i] = HUGE.add(BigInteger.valueOf(rnd.nextInt(len)));
123            return result;
124        }
125    };
126
127    public abstract Object[] build(int len);
128
129    public void resetRandom() {
130        rnd = new Random(666);
131    }
132
133    private static Random rnd = new Random(666);
134
135    private static void swap(Object[] a, int i, int j) {
136        Object t = a[i];
137        a[i] = a[j];
138        a[j] = t;
139    }
140
141    private static BigInteger HUGE = BigInteger.ONE.shiftLeft(100);
142}
143