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1
31
32 package org.antlr.works.visualization.graphics.primitive;
33
34 import java.util.Map  ;
35
36
41
42 public class GLiteral {
43
44 public static final String OP_SUB = "-";
45 public static final String OP_MAX = "#";
46 public static final String OP_LPAREN = "(";
47 public static final String OP_RPAREN = ")";
48 public static final String OP_COMA = ",";
49
50 public static String substract(String a, String b) {
51 return a+OP_SUB+OP_LPAREN+b+OP_RPAREN;
52 }
53
54 public static String add(String a, String b) {
55 return a+b;
56 }
57
58 public static String max(String a, String b) {
59 boolean anull = a == null || a.length() == 0;
60 boolean bnull = b == null || b.length() == 0;
61 if(anull && bnull)
62 return "";
63 else if(anull)
64 return b;
65 else if(bnull)
66 return a;
67 else
68 return OP_MAX+OP_LPAREN+a+OP_COMA+b+OP_RPAREN;
69 }
70
71 public static float evaluate(String s, Map <String ,Float > values) {
72 if(s == null)
73 return 0;
74
75 return new Evaluator(s, values).evaluate();
76 }
77
78 private static class Evaluator {
79
80 public String s;
81 public Map <String ,Float > values;
82 public int position;
83
84 public Evaluator(String s, Map <String ,Float > values) {
85 this.s = s;
86 this.values = values;
87 }
88
89 public float evaluate() {
90 position = 0;
91 return eval();
92 }
93
94 private float eval() {
95 float _value = 0;
96
97 do {
98 Float v = values.get(c());
99 if(v != null) {
100 _value += v.floatValue();
101 } else {
102 if(c().equals(OP_SUB))
103 _value -= evaluate_sub();
104 else if(c().equals(OP_MAX))
105 _value += evaluate_max();
106 else if(c().equals(OP_RPAREN))
107 break;
108 else if(c().equals(OP_COMA))
109 break;
110 else
111 System.err.println("** Evaluator: unexpected token \""+c()+"\"");
112 }
113 } while(nextChar());
114
115 return _value;
116 }
117
118 private float evaluate_sub() {
119 match(OP_SUB);
120 match(OP_LPAREN);
121 return eval();
122 }
123
124 private float evaluate_max() {
125 match(OP_MAX);
126 match(OP_LPAREN);
127 float a = eval();
128 match(OP_COMA);
129 float b = eval();
130 return Math.max(a,b);
131 }
132
133 private boolean nextChar() {
134 position++;
135 return position<s.length();
136 }
137
138 private void match(String token) {
139 if(c().equals(token))
140 nextChar();
141 else
142 System.err.println("** Evaluator: unexpected token \""+c()+"\"");
143 }
144
145 private String c() {
146 return s.substring(position, position+1);
147 }
148 }
149 }
150 |
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