Mercurial > lasercutter

     1 /**

     2  *   Copyright (c) Rich Hickey. All rights reserved.

     3  *   The use and distribution terms for this software are covered by the

     4  *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

     5  *   which can be found in the file epl-v10.html at the root of this distribution.

     6  *   By using this software in any fashion, you are agreeing to be bound by

     7  * 	 the terms of this license.

     8  *   You must not remove this notice, or any other, from this software.

     9  **/

    10 

    11 /* rich Apr 19, 2008 */

    12 

    13 package clojure.lang;

    14 

    15 import java.math.BigInteger;

    16 import java.util.Map;

    17 import java.util.concurrent.ConcurrentHashMap;

    18 import java.lang.ref.SoftReference;

    19 import java.lang.ref.ReferenceQueue;

    20 import java.lang.ref.Reference;

    21 

    22 public class Util{

    23 static public boolean equiv(Object k1, Object k2){

    24 	if(k1 == k2)

    25 		return true;

    26 	if(k1 != null)

    27 		{

    28 		if(k1 instanceof Number && k2 instanceof Number)

    29 			return Numbers.equiv(k1, k2);

    30 		else if(k1 instanceof IPersistentCollection || k2 instanceof IPersistentCollection)

    31 			return pcequiv(k1,k2);

    32 		return k1.equals(k2);

    33 		}

    34 	return false;

    35 }

    36 

    37 static public boolean pcequiv(Object k1, Object k2){

    38 	if(k1 instanceof IPersistentCollection)

    39 		return ((IPersistentCollection)k1).equiv(k2);

    40 	return ((IPersistentCollection)k2).equiv(k1);

    41 }

    42 

    43 static public boolean equals(Object k1, Object k2){

    44 	if(k1 == k2)

    45 		return true;

    46 	return k1 != null && k1.equals(k2);

    47 }

    48 

    49 static public boolean identical(Object k1, Object k2){

    50 	return k1 == k2;

    51 }

    52 

    53 static public Class classOf(Object x){

    54 	if(x != null)

    55 		return x.getClass();

    56 	return null;

    57 }

    58 

    59 static public int compare(Object k1, Object k2){

    60 	if(k1 == k2)

    61 		return 0;

    62 	if(k1 != null)

    63 		{

    64 		if(k2 == null)

    65 			return 1;

    66 		if(k1 instanceof Number)

    67 			return Numbers.compare((Number) k1, (Number) k2);

    68 		return ((Comparable) k1).compareTo(k2);

    69 		}

    70 	return -1;

    71 }

    72 

    73 static public int hash(Object o){

    74 	if(o == null)

    75 		return 0;

    76 	return o.hashCode();

    77 }

    78 

    79 static public int hashCombine(int seed, int hash){

    80 	//a la boost

    81 	seed ^= hash + 0x9e3779b9 + (seed << 6) + (seed >> 2);

    82 	return seed;

    83 }

    84 

    85 static public boolean isPrimitive(Class c){

    86 	return c != null && c.isPrimitive() && !(c == Void.TYPE);

    87 }

    88 

    89 static public boolean isInteger(Object x){

    90 	return x instanceof Integer

    91 			|| x instanceof Long

    92 			|| x instanceof BigInteger;

    93 }

    94 

    95 static public Object ret1(Object ret, Object nil){

    96 		return ret;

    97 }

    98 

    99 static public ISeq ret1(ISeq ret, Object nil){

   100 		return ret;

   101 }

   102 

   103 static public <K,V> void clearCache(ReferenceQueue rq, ConcurrentHashMap<K, SoftReference<V>> cache){

   104 		//cleanup any dead entries

   105 	if(rq.poll() != null)

   106 		{

   107 		while(rq.poll() != null)

   108 			;

   109 		for(Map.Entry<K, SoftReference<V>> e : cache.entrySet())

   110 			{

   111 			if(e.getValue().get() == null)

   112 				cache.remove(e.getKey(), e.getValue());

   113 			}

   114 		}

   115 }

   116 }
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
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