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1
25
26 package org.jrobin.core;
27
28 import java.util.StringTokenizer  ;
29
30 class RpnCalculator {
31 static final String VAR_PLACEHOLDER = "value";
32
33 private static final byte TOK_VAR = 0;
34 private static final byte TOK_NUM = 1;
35 private static final byte TOK_PLUS = 2;
36 private static final byte TOK_MINUS = 3;
37 private static final byte TOK_MULT = 4;
38 private static final byte TOK_DIV = 5;
39 private static final byte TOK_MOD = 6;
40 private static final byte TOK_SIN = 7;
41 private static final byte TOK_COS = 8;
42 private static final byte TOK_LOG = 9;
43 private static final byte TOK_EXP = 10;
44 private static final byte TOK_FLOOR = 11;
45 private static final byte TOK_CEIL = 12;
46 private static final byte TOK_ROUND = 13;
47 private static final byte TOK_POW = 14;
48 private static final byte TOK_ABS = 15;
49 private static final byte TOK_SQRT = 16;
50 private static final byte TOK_RANDOM = 17;
51 private static final byte TOK_LT = 18;
52 private static final byte TOK_LE = 19;
53 private static final byte TOK_GT = 20;
54 private static final byte TOK_GE = 21;
55 private static final byte TOK_EQ = 22;
56 private static final byte TOK_IF = 23;
57 private static final byte TOK_MIN = 24;
58 private static final byte TOK_MAX = 25;
59 private static final byte TOK_LIMIT = 26;
60 private static final byte TOK_DUP = 27;
61 private static final byte TOK_EXC = 28;
62 private static final byte TOK_POP = 29;
63 private static final byte TOK_UN = 30;
64 private static final byte TOK_UNKN = 31;
65 private static final byte TOK_PI = 34;
68 private static final byte TOK_E = 35;
69 private static final byte TOK_AND = 36;
70 private static final byte TOK_OR = 37;
71 private static final byte TOK_XOR = 38;
72
73 private String [] tokens;
74 private byte[] tokenCodes;
75 private double[] parsedDoubles;
76 private RpnStack stack = new RpnStack();
77
78 private String rpnExpression;
79 private double value;
80
82 RpnCalculator(String rpnExpression) throws RrdException {
83 this.rpnExpression = rpnExpression;
84 createTokens();
85 }
86
87 void setValue(double value) {
88 this.value = value;
89 }
90
91
96
97 private void createTokens() throws RrdException {
98 StringTokenizer st = new StringTokenizer (rpnExpression, ",");
99 int count = st.countTokens();
100 tokens = new String [count];
101 tokenCodes = new byte[count];
102 parsedDoubles = new double[count];
103 for(int i = 0; st.hasMoreTokens(); i++) {
104 String token = st.nextToken();
105 tokens[i] = token;
106 byte tokenCode = findTokenCode(token);
107 tokenCodes[i] = tokenCode;
108 if(tokenCode == TOK_NUM) {
109 parsedDoubles[i] = Double.parseDouble(token);
110 }
111 }
112 }
113
114 private byte findTokenCode(String token) throws RrdException {
115 if(isVariable(token)) {
116 return TOK_VAR;
117 }
118 else if(isNumber(token)) {
119 return TOK_NUM;
120 }
121 else if(token.equals("+")) {
122 return TOK_PLUS;
123 }
124 else if(token.equals("-")) {
125 return TOK_MINUS;
126 }
127 else if(token.equals("*")) {
128 return TOK_MULT;
129 }
130 else if(token.equals("/")) {
131 return TOK_DIV;
132 }
133 else if(token.equals("%")) {
134 return TOK_MOD;
135 }
136 else if(token.equals("SIN")) {
137 return TOK_SIN;
138 }
139 else if(token.equals("COS")) {
140 return TOK_COS;
141 }
142 else if(token.equals("LOG")) {
143 return TOK_LOG;
144 }
145 else if(token.equals("EXP")) {
146 return TOK_EXP;
147 }
148 else if(token.equals("FLOOR")) {
149 return TOK_FLOOR;
150 }
151 else if(token.equals("CEIL")) {
152 return TOK_CEIL;
153 }
154 else if(token.equals("ROUND")) {
155 return TOK_ROUND;
156 }
157 else if(token.equals("POW")) {
158 return TOK_POW;
159 }
160 else if(token.equals("ABS")) {
161 return TOK_ABS;
162 }
163 else if(token.equals("SQRT")) {
164 return TOK_SQRT;
165 }
166 else if(token.equals("RANDOM")) {
167 return TOK_RANDOM;
168 }
169 else if(token.equals("LT")) {
170 return TOK_LT;
171 }
172 else if(token.equals("LE")) {
173 return TOK_LE;
174 }
175 else if(token.equals("GT")) {
176 return TOK_GT;
177 }
178 else if(token.equals("GE")) {
179 return TOK_GE;
180 }
181 else if(token.equals("EQ")) {
182 return TOK_EQ;
183 }
184 else if(token.equals("IF")) {
185 return TOK_IF;
186 }
187 else if(token.equals("MIN")) {
188 return TOK_MIN;
189 }
190 else if(token.equals("MAX")) {
191 return TOK_MAX;
192 }
193 else if(token.equals("LIMIT")) {
194 return TOK_LIMIT;
195 }
196 else if(token.equals("DUP")) {
197 return TOK_DUP;
198 }
199 else if(token.equals("EXC")) {
200 return TOK_EXC;
201 }
202 else if(token.equals("POP")) {
203 return TOK_POP;
204 }
205 else if(token.equals("UN")) {
206 return TOK_UN;
207 }
208 else if(token.equals("UNKN")) {
209 return TOK_UNKN;
210 }
211
212
220 else if(token.equals("PI")) {
221 return TOK_PI;
222 }
223 else if(token.equals("E")) {
224 return TOK_E;
225 }
226 else if(token.equals("AND")) {
227 return TOK_AND;
228 }
229 else if(token.equals("OR")) {
230 return TOK_OR;
231 }
232 else if(token.equals("XOR")) {
233 return TOK_XOR;
234 }
235 else {
236 throw new RrdException("Unknown RPN token encountered: " + token);
237 }
238 }
239
240 private static boolean isNumber(String token) {
241 try {
242 Double.parseDouble(token);
243 return true;
244 }
245 catch(NumberFormatException nfe) {
246 return false;
247 }
248 }
249
250 private static boolean isVariable(String token) {
251 return token.equals(VAR_PLACEHOLDER);
252 }
253
254 double calculate() throws RrdException {
255 resetCalculator();
256 for(int i = 0; i < tokenCodes.length; i++) {
257 byte tokenCode = tokenCodes[i];
258 double x1, x2, x3;
259 switch(tokenCode) {
260 case TOK_NUM:
261 push(parsedDoubles[i]); break;
262 case TOK_VAR:
263 push(value); break;
264 case TOK_PLUS:
265 push(pop() + pop()); break;
266 case TOK_MINUS:
267 x2 = pop(); x1 = pop(); push(x1 - x2); break;
268 case TOK_MULT:
269 push(pop() * pop()); break;
270 case TOK_DIV:
271 x2 = pop(); x1 = pop(); push(x1 / x2); break;
272 case TOK_MOD:
273 x2 = pop(); x1 = pop(); push(x1 % x2); break;
274 case TOK_SIN:
275 push(Math.sin(pop())); break;
276 case TOK_COS:
277 push(Math.cos(pop())); break;
278 case TOK_LOG:
279 push(Math.log(pop())); break;
280 case TOK_EXP:
281 push(Math.exp(pop())); break;
282 case TOK_FLOOR:
283 push(Math.floor(pop())); break;
284 case TOK_CEIL:
285 push(Math.ceil(pop())); break;
286 case TOK_ROUND:
287 push(Math.round(pop())); break;
288 case TOK_POW:
289 x2 = pop(); x1 = pop(); push(Math.pow(x1, x2)); break;
290 case TOK_ABS:
291 push(Math.abs(pop())); break;
292 case TOK_SQRT:
293 push(Math.sqrt(pop())); break;
294 case TOK_RANDOM:
295 push(Math.random()); break;
296 case TOK_LT:
297 x2 = pop(); x1 = pop(); push(x1 < x2? 1: 0); break;
298 case TOK_LE:
299 x2 = pop(); x1 = pop(); push(x1 <= x2? 1: 0); break;
300 case TOK_GT:
301 x2 = pop(); x1 = pop(); push(x1 > x2? 1: 0); break;
302 case TOK_GE:
303 x2 = pop(); x1 = pop(); push(x1 >= x2? 1: 0); break;
304 case TOK_EQ:
305 x2 = pop(); x1 = pop(); push(x1 == x2? 1: 0); break;
306 case TOK_IF:
307 x3 = pop(); x2 = pop(); x1 = pop(); push(x1 != 0? x2: x3); break;
308 case TOK_MIN:
309 push(Math.min(pop(), pop())); break;
310 case TOK_MAX:
311 push(Math.max(pop(), pop())); break;
312 case TOK_LIMIT:
313 x3 = pop(); x2 = pop(); x1 = pop();
314 push(x1 < x2 || x1 > x3? Double.NaN: x1); break;
315 case TOK_DUP:
316 x1 = pop(); push(x1); push(x1); break;
317 case TOK_EXC:
318 x2 = pop(); x1 = pop(); push(x2); push(x1); break;
319 case TOK_POP:
320 pop(); break;
321 case TOK_UN:
322 push(Double.isNaN(pop())? 1: 0); break;
323 case TOK_UNKN:
324 push(Double.NaN); break;
325
331 case TOK_PI:
332 push(Math.PI); break;
333 case TOK_E:
334 push(Math.E); break;
335 case TOK_AND:
336 x2 = pop(); x1 = pop(); push((x1 != 0 && x2 != 0)? 1: 0); break;
337 case TOK_OR:
338 x2 = pop(); x1 = pop(); push((x1 != 0 || x2 != 0)? 1: 0); break;
339 case TOK_XOR:
340 x2 = pop(); x1 = pop();
341 push(((x1 != 0 && x2 == 0) || (x1 == 0 && x2 != 0))? 1: 0); break;
342 default:
343 throw new RrdException("Unexpected RPN token encountered [" +
344 tokenCode + "]");
345 }
346 }
347 double retVal = pop();
348 if(!isStackEmpty()) {
349 throw new RrdException("Stack not empty at the end of calculation. " +
350 "Probably bad RPN expression");
351 }
352 return retVal;
353 }
354
355 void push(double x) throws RrdException {
356 stack.push(x);
357 }
358
359 double pop() throws RrdException {
360 return stack.pop();
361 }
362
363 void resetCalculator() {
364 stack.reset();
365 }
366
367 boolean isStackEmpty() {
368 return stack.isEmpty();
369 }
370
371 class RpnStack {
372 static final int MAX_STACK_SIZE = 1000;
373 private double[] stack = new double[MAX_STACK_SIZE];
374 private int pos = 0;
375
376 void push(double x) throws RrdException {
377 if(pos >= MAX_STACK_SIZE) {
378 throw new RrdException(
379 "PUSH failed, RPN stack full [" + MAX_STACK_SIZE + "]");
380 }
381 stack[pos++] = x;
382 }
383
384 double pop() throws RrdException {
385 if(pos <= 0) {
386 throw new RrdException("POP failed, RPN stack is empty ");
387 }
388 return stack[--pos];
389 }
390
391 void reset() {
392 pos = 0;
393 }
394
395 boolean isEmpty() {
396 return pos == 0;
397 }
398 }
399
400
407 }
408 |
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