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
|
package ch.obermuhlner.math.big.stream;
import java.util.Comparator;
import java.util.Spliterator;
import java.util.Spliterators.AbstractSpliterator;
import java.util.function.Consumer;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import ch.obermuhlner.math.big.BigFloat;
import ch.obermuhlner.math.big.BigFloat.Context;
/**
* Provides constructor methods for streams of {@link BigFloat} elements.
*/
public class BigFloatStream {
/**
* Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
* (inclusive) to {@code endExclusive} (exclusive) by an incremental {@code step}.
*
* <p>An equivalent sequence of increasing values can be produced
* sequentially using a {@code for} loop as follows:
* <pre>for (BigFloat i = startInclusive; i.isLessThan(endExclusive); i = i.add(step)) {
// ...
}</pre>
*
* @param startInclusive the (inclusive) initial value
* @param endExclusive the exclusive upper bound
* @param step the step between elements
* @return a sequential {@code Stream<BigFloat>}
*/
public static Stream<BigFloat> range(BigFloat startInclusive, BigFloat endExclusive, BigFloat step) {
if (step.isZero()) {
throw new IllegalArgumentException("invalid step: 0");
}
if (endExclusive.subtract(startInclusive).signum() != step.signum()) {
return Stream.empty();
}
return StreamSupport.stream(new BigFloatSpliterator(startInclusive, endExclusive, false, step), false);
}
/**
* Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
* (inclusive) to {@code endExclusive} (exclusive) by an incremental {@code step}.
*
* <p>{@link Context#valueOf(long)} is used to convert the {@code long} values.</p>
*
* @param startInclusive the (inclusive) initial value
* @param endExclusive the exclusive upper bound
* @param step the step between elements
* @param context the {@link Context} used to convert the {@code long} values
* @return a sequential {@code Stream<BigFloat>}
* @see #range(BigFloat, BigFloat, BigFloat)
*/
public static Stream<BigFloat> range(long startInclusive, long endExclusive, long step, Context context) {
return range(context.valueOf(startInclusive), context.valueOf(endExclusive), context.valueOf(step));
}
/**
* Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
* (inclusive) to {@code endExclusive} (exclusive) by an incremental {@code step}.
*
* <p>{@link Context#valueOf(double)} is used to convert the {@code double} values.</p>
*
* @param startInclusive the (inclusive) initial value
* @param endExclusive the exclusive upper bound
* @param step the step between elements
* @param context the {@link Context} used to convert the {@code double} values
* @return a sequential {@code Stream<BigFloat>}
* @see #range(BigFloat, BigFloat, BigFloat)
*/
public static Stream<BigFloat> range(double startInclusive, double endExclusive, double step, Context context) {
return range(context.valueOf(startInclusive), context.valueOf(endExclusive), context.valueOf(step));
}
/**
* Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
* (inclusive) to {@code endInclusive} (inclusive) by an incremental {@code step}.
*
* <p>An equivalent sequence of increasing values can be produced
* sequentially using a {@code for} loop as follows:
* <pre>for (BigFloat i = startInclusive; i.isLessThanOrEqual(endInclusive); i = i.add(step)) {
//...
}
</pre>
*
* @param startInclusive the (inclusive) initial value
* @param endInclusive the inclusive upper bound
* @param step the step between elements
* @return a sequential {@code Stream<BigFloat>}
*/
public static Stream<BigFloat> rangeClosed(BigFloat startInclusive, BigFloat endInclusive, BigFloat step) {
if (step.isZero()) {
throw new IllegalArgumentException("invalid step: 0");
}
if (endInclusive.subtract(startInclusive).signum() == -step.signum()) {
return Stream.empty();
}
return StreamSupport.stream(new BigFloatSpliterator(startInclusive, endInclusive, true, step), false);
}
/**
* Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
* (inclusive) to {@code endInclusive} (inclusive) by an incremental {@code step}.
*
* <p>{@link Context#valueOf(long)} is used to convert the {@code long} values.</p>
*
* @param startInclusive the (inclusive) initial value
* @param endInclusive the inclusive upper bound
* @param step the step between elements
* @param context the {@link Context} used to convert the {@code long} values
* @return a sequential {@code Stream<BigFloat>}
* @see #rangeClosed(BigFloat, BigFloat, BigFloat)
*/
public static Stream<BigFloat> rangeClosed(long startInclusive, long endInclusive, long step, Context context) {
return rangeClosed(context.valueOf(startInclusive), context.valueOf(endInclusive), context.valueOf(step));
}
/**
* Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
* (inclusive) to {@code endInclusive} (inclusive) by an incremental {@code step}.
*
* <p>{@link Context#valueOf(double)} is used to convert the {@code double} values.</p>
*
* @param startInclusive the (inclusive) initial value
* @param endInclusive the inclusive upper bound
* @param step the step between elements
* @param context the {@link Context} used to convert the {@code double} values
* @return a sequential {@code Stream<BigFloat>}
* @see #rangeClosed(BigFloat, BigFloat, BigFloat)
*/
public static Stream<BigFloat> rangeClosed(double startInclusive, double endInclusive, double step, Context context) {
return rangeClosed(context.valueOf(startInclusive), context.valueOf(endInclusive), context.valueOf(step));
}
private static class BigFloatSpliterator extends AbstractSpliterator<BigFloat> {
private BigFloat value;
private BigFloat step;
private long count;
public BigFloatSpliterator(BigFloat startInclusive, BigFloat step, long count) {
super(count,
Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED | Spliterator.SORTED);
this.value = startInclusive;
this.step = step;
this.count = count;
}
public BigFloatSpliterator(BigFloat startInclusive, BigFloat end, boolean inclusive, BigFloat step) {
this(startInclusive, step, estimatedCount(startInclusive, end, inclusive, step));
}
private static long estimatedCount(BigFloat startInclusive, BigFloat end, boolean inclusive, BigFloat step) {
BigFloat count = end.subtract(startInclusive).divide(step);
long result = count.toLong();
if (count.getFractionalPart().signum() != 0) {
result++;
} else {
if (inclusive) {
result++;
}
}
return result;
}
@Override
public Comparator<? super BigFloat> getComparator() {
if (step.signum() < 0) {
return Comparator.reverseOrder();
}
return null;
}
@Override
public boolean tryAdvance(Consumer<? super BigFloat> action) {
if (count == 0) {
return false;
}
action.accept(value);
value = value.add(step);
count--;
return true;
}
@Override
public void forEachRemaining(Consumer<? super BigFloat> action) {
while (count > 0) {
action.accept(value);
value = value.add(step);
count--;
}
}
@Override
public Spliterator<BigFloat> trySplit() {
long firstHalfCount = count / 2;
if (firstHalfCount == 0) {
return null;
}
long secondHalfCount = count - firstHalfCount;
count = firstHalfCount;
BigFloat startSecondHalf = value.add(step.multiply(firstHalfCount));
return new BigFloatSpliterator(startSecondHalf, step, secondHalfCount);
}
}
}
|
