001 package aima.util;
002
003 import java.util.List;
004
005 /**
006 * @author Ciaran O'Reilly
007 * see: http://demonstrations.wolfram.com/MixedRadixNumberRepresentations/
008 * for useful example.
009 */
010 public class MixedRadixNumber extends Number {
011 //
012 private static final long serialVersionUID = 1L;
013 //
014 private long value = 0L;
015 private long maxValue = 0L;
016 private int[] radixs = null;
017 private int[] currentNumeralValue = null;
018 private boolean recalculate = true;
019
020 public MixedRadixNumber(long value, int[] radixs) {
021 this.value = value;
022 this.radixs = new int[radixs.length];
023 System.arraycopy(radixs, 0, this.radixs, 0, radixs.length);
024 calculateMaxValue();
025 }
026
027 public MixedRadixNumber(long value, List<Integer> radixs) {
028 this.value = value;
029 this.radixs = new int[radixs.size()];
030 for (int i = 0; i < radixs.size(); i++) {
031 this.radixs[i] = radixs.get(i);
032 }
033 calculateMaxValue();
034 }
035
036 public long getMaxAllowedValue() {
037 return maxValue;
038 }
039
040 public boolean increment() {
041 if (value < maxValue) {
042 value++;
043 recalculate = true;
044 return true;
045 }
046
047 return false;
048 }
049
050 public boolean decrement() {
051 if (value > 0) {
052 value--;
053 recalculate = true;
054 return true;
055 }
056 return false;
057 }
058
059 public int getCurrentNumeralValue(int atPosition) {
060 if (atPosition >= 0 && atPosition < radixs.length) {
061 if (recalculate) {
062 long quotient = value;
063 for (int i = 0; i < radixs.length; i++) {
064 if (0 != quotient) {
065 currentNumeralValue[i] = (int) quotient % radixs[i];
066 quotient = quotient / radixs[i];
067 } else {
068 currentNumeralValue[i] = 0;
069 }
070
071 }
072 recalculate = false;
073 }
074 return currentNumeralValue[atPosition];
075 }
076 throw new IllegalArgumentException("Argument atPosition must be >=0 and < "+radixs.length);
077 }
078
079 //
080 // START-Number
081 public int intValue() {
082 return (int) longValue();
083 }
084
085 public long longValue() {
086 return value;
087 }
088
089 public float floatValue() {
090 return longValue();
091 }
092
093 public double doubleValue() {
094 return longValue();
095 }
096 // END-Number
097 //
098
099 public String toString() {
100 StringBuilder sb = new StringBuilder();
101
102 for (int i = 0; i < radixs.length; i++) {
103 sb.append("[");
104 sb.append(this.getCurrentNumeralValue(i));
105 sb.append("]");
106 }
107
108 return sb.toString();
109 }
110
111 //
112 // PRIVATE
113 //
114 private void calculateMaxValue() {
115 if (0 == radixs.length) {
116 throw new IllegalArgumentException("At least 1 radix must be defined.");
117 }
118 for (int i = 0; i < radixs.length; i++) {
119 if (radixs[i] < 2) {
120 throw new IllegalArgumentException("Invalid radix, must be >= 2");
121 }
122 }
123
124 // Calcualte the maxValue allowed
125 maxValue = radixs[0];
126 for (int i = 1; i < radixs.length; i++) {
127 maxValue *= radixs[i];
128 }
129 maxValue -= 1;
130
131 if (value > maxValue) {
132 throw new IllegalArgumentException("The value ["+value+"] cannot be represented with the radixs provided, max value is " + maxValue);
133 }
134
135 currentNumeralValue = new int[radixs.length];
136 }
137 }