001 /*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the
010 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
011 * express or implied. See the License for the specific language governing permissions and
012 * limitations under the License.
013 */
014
015 package com.google.common.primitives;
016
017 import static com.google.common.base.Preconditions.checkArgument;
018 import static com.google.common.base.Preconditions.checkNotNull;
019
020 import com.google.common.annotations.Beta;
021 import com.google.common.annotations.GwtCompatible;
022
023 import java.io.Serializable;
024 import java.math.BigInteger;
025
026 import javax.annotation.Nullable;
027
028 /**
029 * A wrapper class for unsigned {@code long} values, supporting arithmetic operations.
030 *
031 * <p>In some cases, when speed is more important than code readability, it may be faster simply to
032 * treat primitive {@code long} values as unsigned, using the methods from {@link UnsignedLongs}.
033 *
034 * <p>See the Guava User Guide article on <a href=
035 * "http://code.google.com/p/guava-libraries/wiki/PrimitivesExplained#Unsigned_support">
036 * unsigned primitive utilities</a>.
037 *
038 * @author Louis Wasserman
039 * @author Colin Evans
040 * @since 11.0
041 */
042 @Beta
043 @GwtCompatible(serializable = true)
044 public final class UnsignedLong extends Number implements Comparable<UnsignedLong>, Serializable {
045
046 private static final long UNSIGNED_MASK = 0x7fffffffffffffffL;
047
048 public static final UnsignedLong ZERO = new UnsignedLong(0);
049 public static final UnsignedLong ONE = new UnsignedLong(1);
050 public static final UnsignedLong MAX_VALUE = new UnsignedLong(-1L);
051
052 private final long value;
053
054 private UnsignedLong(long value) {
055 this.value = value;
056 }
057
058 /**
059 * Returns an {@code UnsignedLong} that, when treated as signed, is equal to {@code value}. The
060 * inverse operation is {@link #longValue()}.
061 *
062 * <p>Put another way, if {@code value} is negative, the returned result will be equal to
063 * {@code 2^64 + value}; otherwise, the returned result will be equal to {@code value}.
064 */
065 public static UnsignedLong asUnsigned(long value) {
066 return new UnsignedLong(value);
067 }
068
069 /**
070 * Returns a {@code UnsignedLong} representing the same value as the specified {@code BigInteger}
071 * . This is the inverse operation of {@link #bigIntegerValue()}.
072 *
073 * @throws IllegalArgumentException if {@code value} is negative or {@code value >= 2^64}
074 */
075 public static UnsignedLong valueOf(BigInteger value) {
076 checkNotNull(value);
077 checkArgument(value.signum() >= 0 && value.bitLength() <= Long.SIZE,
078 "value (%s) is outside the range for an unsigned long value", value);
079 return asUnsigned(value.longValue());
080 }
081
082 /**
083 * Returns an {@code UnsignedLong} holding the value of the specified {@code String}, parsed as
084 * an unsigned {@code long} value.
085 *
086 * @throws NumberFormatException if the string does not contain a parsable unsigned {@code long}
087 * value
088 */
089 public static UnsignedLong valueOf(String string) {
090 return valueOf(string, 10);
091 }
092
093 /**
094 * Returns an {@code UnsignedLong} holding the value of the specified {@code String}, parsed as
095 * an unsigned {@code long} value in the specified radix.
096 *
097 * @throws NumberFormatException if the string does not contain a parsable unsigned {@code long}
098 * value, or {@code radix} is not between {@link Character#MIN_RADIX} and
099 * {@link Character#MAX_RADIX}
100 */
101 public static UnsignedLong valueOf(String string, int radix) {
102 return asUnsigned(UnsignedLongs.parseUnsignedLong(string, radix));
103 }
104
105 /**
106 * Returns the result of adding this and {@code val}. If the result would have more than 64 bits,
107 * returns the low 64 bits of the result.
108 */
109 public UnsignedLong add(UnsignedLong val) {
110 checkNotNull(val);
111 return asUnsigned(this.value + val.value);
112 }
113
114 /**
115 * Returns the result of subtracting this and {@code val}. If the result would be negative,
116 * returns the low 64 bits of the result.
117 */
118 public UnsignedLong subtract(UnsignedLong val) {
119 checkNotNull(val);
120 return asUnsigned(this.value - val.value);
121 }
122
123 /**
124 * Returns the result of multiplying this and {@code val}. If the result would have more than 64
125 * bits, returns the low 64 bits of the result.
126 */
127 public UnsignedLong multiply(UnsignedLong val) {
128 checkNotNull(val);
129 return asUnsigned(value * val.value);
130 }
131
132 /**
133 * Returns the result of dividing this by {@code val}.
134 */
135 public UnsignedLong divide(UnsignedLong val) {
136 checkNotNull(val);
137 return asUnsigned(UnsignedLongs.divide(value, val.value));
138 }
139
140 /**
141 * Returns the remainder of dividing this by {@code val}.
142 */
143 public UnsignedLong remainder(UnsignedLong val) {
144 checkNotNull(val);
145 return asUnsigned(UnsignedLongs.remainder(value, val.value));
146 }
147
148 /**
149 * Returns the value of this {@code UnsignedLong} as an {@code int}.
150 */
151 @Override
152 public int intValue() {
153 return (int) value;
154 }
155
156 /**
157 * Returns the value of this {@code UnsignedLong} as a {@code long}. This is an inverse operation
158 * to {@link #asUnsigned}.
159 *
160 * <p>Note that if this {@code UnsignedLong} holds a value {@code >= 2^63}, the returned value
161 * will be equal to {@code this - 2^64}.
162 */
163 @Override
164 public long longValue() {
165 return value;
166 }
167
168 /**
169 * Returns the value of this {@code UnsignedLong} as a {@code float}, analogous to a widening
170 * primitive conversion from {@code long} to {@code float}, and correctly rounded.
171 */
172 @Override
173 public float floatValue() {
174 @SuppressWarnings("cast")
175 float fValue = (float) (value & UNSIGNED_MASK);
176 if (value < 0) {
177 fValue += 0x1.0p63f;
178 }
179 return fValue;
180 }
181
182 /**
183 * Returns the value of this {@code UnsignedLong} as a {@code double}, analogous to a widening
184 * primitive conversion from {@code long} to {@code double}, and correctly rounded.
185 */
186 @Override
187 public double doubleValue() {
188 @SuppressWarnings("cast")
189 double dValue = (double) (value & UNSIGNED_MASK);
190 if (value < 0) {
191 dValue += 0x1.0p63;
192 }
193 return dValue;
194 }
195
196 /**
197 * Returns the value of this {@code UnsignedLong} as a {@link BigInteger}.
198 */
199 public BigInteger bigIntegerValue() {
200 BigInteger bigInt = BigInteger.valueOf(value & UNSIGNED_MASK);
201 if (value < 0) {
202 bigInt = bigInt.setBit(Long.SIZE - 1);
203 }
204 return bigInt;
205 }
206
207 @Override
208 public int compareTo(UnsignedLong o) {
209 checkNotNull(o);
210 return UnsignedLongs.compare(value, o.value);
211 }
212
213 @Override
214 public int hashCode() {
215 return Longs.hashCode(value);
216 }
217
218 @Override
219 public boolean equals(@Nullable Object obj) {
220 if (obj instanceof UnsignedLong) {
221 UnsignedLong other = (UnsignedLong) obj;
222 return value == other.value;
223 }
224 return false;
225 }
226
227 /**
228 * Returns a string representation of the {@code UnsignedLong} value, in base 10.
229 */
230 @Override
231 public String toString() {
232 return UnsignedLongs.toString(value);
233 }
234
235 /**
236 * Returns a string representation of the {@code UnsignedLong} value, in base {@code radix}. If
237 * {@code radix < Character.MIN_RADIX} or {@code radix > Character.MAX_RADIX}, the radix
238 * {@code 10} is used.
239 */
240 public String toString(int radix) {
241 return UnsignedLongs.toString(value, radix);
242 }
243 }