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package org.checkerframework.dataflow.util;
/**
* Utility class to implement the {@code hashCode} method.
*
* @author Stefan Heule
*/
public class HashCodeUtils {
/** Odd prime number. */
private static int prime = 31;
/** Seed. */
private static int seed = 17;
/** Add a boolean value to a given hash. */
public static int hash(int hash, boolean item) {
return hash * prime + (item ? 1 : 0);
}
/** Add a char value to a given hash. */
public static int hash(int hash, char item) {
return hash * prime + item;
}
/** Add an int value to a given hash. */
public static int hash(int hash, int item) {
return hash * prime + item;
}
/** Add a long value to a given hash. */
public static int hash(int hash, long item) {
return hash * prime + (int) (item ^ (item >>> 32));
}
/** Add a float value to a given hash. */
public static int hash(int hash, float item) {
return hash * prime + Float.floatToIntBits(item);
}
/** Add a double value to a given hash. */
public static int hash(int hash, double item) {
long l = Double.doubleToLongBits(item);
return seed * prime + (int) (l ^ (l >>> 32));
}
/** Add an object to a given hash. */
public static int hash(int hash, Object item) {
if (item == null) {
return hash * prime;
}
return hash * prime + item.hashCode();
}
/** Hash a boolean value. */
public static int hash(boolean item) {
return (item ? 1 : 0);
}
/** Hash a char value. */
public static int hash(char item) {
return item;
}
/** Hash an int value. */
public static int hash(int item) {
return item;
}
/** Hash a long value. */
public static int hash(long item) {
return (int) (item ^ (item >>> 32));
}
/** Hash a float value. */
public static int hash(float item) {
return Float.floatToIntBits(item);
}
/** Hash a double value. */
public static int hash(double item) {
long l = Double.doubleToLongBits(item);
return (int) (l ^ (l >>> 32));
}
/** Hash an object. */
public static int hash(Object item) {
if (item == null) {
return 0;
}
return item.hashCode();
}
/** Hash multiple objects. */
public static int hash(Object... items) {
int result = seed;
for (Object item : items) {
result = result * prime + (item == null ? 0 : item.hashCode());
}
return result;
}
}
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