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hashcode, equals and compareTo

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This commit is contained in:
Florian Steurer 2015-10-24 18:53:11 +02:00
parent b0153be1cd
commit 3d38ea2e08
1 changed files with 47 additions and 16 deletions
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57
src/de/dhbwstuttgart/typinference/unify/model/MType.java
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@ -2,16 +2,18 @@ package de.dhbwstuttgart.typinference.unify.model;
import java.util.Arrays; import java.util.Arrays;
import de.dhbwstuttgart.typeinference.exceptions.NotImplementedException;
/** /**
* *
* @author DH10STF * @author DH10STF
* *
* SPEEDUP * TODO SPEEDUP
* - Caching of the results * - Caching of the results
* - Global map from int to mtype und mtype[] array mit int[] austauschen und wenn nötig nachschlagen
* - Vorteil: Jeder Typ wäre globally unique -> Memory effizient
* - Nachteil: Nachschlagen kostet zeit, Dictionary muss gemanaged werden
* - TypeArgs in HashCode berechnung stärker / weniger einbeziehen
*/ */
public class MType { public class MType implements Comparable<MType>{
/** /**
* First three bits indicate the meta type: * First three bits indicate the meta type:
@ -23,11 +25,12 @@ public class MType {
* *
* Advantages of using a unique identifier for mapping: * Advantages of using a unique identifier for mapping:
* - Fast checks (Equality and Membership) * - Fast checks (Equality and Membership)
* - Perfect Hashing * - Easy Hashing
* - Memory efficient
*/ */
private int identifier = 0; private int identifier = 0;
private int[] typeArgs = null; private MType[] typeArgs = null;
/** /**
* Used to mask the first three bits of an integer. * Used to mask the first three bits of an integer.
@ -35,14 +38,11 @@ public class MType {
*/ */
private final int mask = -53870912; private final int mask = -53870912;
public MType(int identifier, int...typeArgs) { public MType(int identifier, MType... typeArgs) {
this.identifier = identifier; this.identifier = identifier;
if(typeArgs.length != 0) {
this.typeArgs = Arrays.copyOf(typeArgs, typeArgs.length); this.typeArgs = Arrays.copyOf(typeArgs, typeArgs.length);
Arrays.sort(typeArgs); Arrays.sort(typeArgs);
} }
}
public boolean isSimpleType() { public boolean isSimpleType() {
return (identifier & mask) == 0; return (identifier & mask) == 0;
@ -68,17 +68,48 @@ public class MType {
return identifier; return identifier;
} }
public MType[] getTypeArgs() {
return typeArgs;
}
@Override @Override
public boolean equals(Object obj) { public boolean equals(Object obj) {
if(!(obj instanceof MType)) if(!(obj instanceof MType))
return false; return false;
if(obj.hashCode() != hashCode())
return false;
throw new NotImplementedException(); MType other = (MType) obj;
if(other.getIdentifier() != identifier)
return false;
MType[] otherTypeArgs = other.getTypeArgs();
if(otherTypeArgs.length != typeArgs.length)
return false;
for(int i = 0; i < typeArgs.length; i++)
if(!typeArgs[i].equals(otherTypeArgs[i]))
return false;
return true;
} }
@Override @Override
public int hashCode() { public int hashCode() {
// TODO Auto-generated method stub return identifier + 31 * typeArgs.length;
return super.hashCode(); }
@Override
public int compareTo(MType o) {
// Comparison is insensitive to type arguments.
if(o.getIdentifier() > identifier)
return -1;
if(o.getIdentifier() < identifier)
return 1;
return 0;
} }
} }