solver.java

用JAVA做的一个手机上的计算器

package xcalc;

import java.util.Enumeration;
import java.util.Stack;
import xcalc.Real;

public final class Solver
{
	public static final String[] C_COMMANDS = 
	{
		"0","1","2","3","4","5","6","7","8","9",		
		".","+","-","*","/","%","^","(",")","PI",
		"e","x","y","ANS","sqrt(","log10(","log2(","ln(","sin(","cos(","tan(",
		"asin(","acos(","atan(","sinh(","cosh(","tanh(","asinh","acosh(","atanh(","fac(",
		";","P(","C(","abs("
	};	
	public static final int K_0 = 0;
	public static final int K_1 = 1;
	public static final int K_2 = 2;
	public static final int K_3 = 3;
	public static final int K_4 = 4;
	public static final int K_5 = 5;
	public static final int K_6 = 6;
	public static final int K_7 = 7;
	public static final int K_8 = 8;
	public static final int K_9 = 9;
	public static final int K_POINT = 10;
	public static final int K_ADD = 11;
	public static final int K_SUB = 12;
	public static final int K_MUL = 13;
	public static final int K_DIV = 14;
	public static final int K_MOD = 15;
	public static final int K_POWER = 16;
	public static final int K_BREAKET_OPEN = 17;
	public static final int K_BREAKET_CLOSE = 18;
	public static final int K_PI = 19;
	public static final int K_E = 20;
	public static final int K_X = 21;
	public static final int K_Y = 22;
	public static final int K_ANS = 23;
	public static final int K_SQRT = 24;
	public static final int K_LOG10 = 25;	
	public static final int K_LOG2 = 26;	
	public static final int K_LN = 27;
	public static final int K_SIN = 28;
	public static final int K_COS = 29;
	public static final int K_TAN = 30;
	public static final int K_ASIN = 31;
	public static final int K_ACOS = 32;
	public static final int K_ATAN = 33;
	public static final int K_SINH = 34;
	public static final int K_COSH = 35;
	public static final int K_TANH = 36;
	public static final int K_ASINH = 37;
	public static final int K_ACOSH = 38;
	public static final int K_ATANH = 39;
	public static final int K_FAC = 40;
	public static final int K_SEMI = 41;
	public static final int K_PER = 42;	
	public static final int K_COM = 43;	
	public static final int K_ABS = 44;	
	public static final int K_EOF = 100;	
	
	private static Enumeration e;
	private static String lookaheadValue;
	private static int lookaheadKind;
	private static Symbol eq;
	private static Stack tempStack  = new Stack();;
	
	private static void acceptIt() throws Exception{
		//system.out.println("acceptIt");
		if(!e.hasMoreElements()) {
			lookaheadValue ="";
			lookaheadKind = K_EOF;
			return;
		}
		lookaheadValue = (String)e.nextElement();
		lookaheadKind = tokenType(lookaheadValue);
	}
	
	public static int tokenType(String token) throws Exception{
		for(int i = 0; i<C_COMMANDS.length;++i){
			if(token==C_COMMANDS[i])
				return i;
		}		
		throw new Exception("Unknown command");
	}

	public static Real solve(Real x, Real y)
	{
		Num.setXVar(x);
		Num.setYVar(y);
		return solve();
	}
	
	public static Real solve(Real x)
	{
		Num.setXVar(x);
		return solve();
	}
	
	public static Real solve()
	{
		//long s = System.currentTimeMillis();
		Real result = eq.eval();
		//System.out.println(System.currentTimeMillis()-s);
		return result;
	}
	
	public static void initialize(Enumeration e) throws Exception
	{
		Solver.e = e;
		Solver.tempStack.removeAllElements();
		acceptIt();
		parse1();
		Solver.eq = (Symbol)tempStack.pop();		
	}
		
//	<1> ::= <2> <1_>
	private static  void parse1() throws Exception{
		//system.out.println("parse1");
	    parse2();
		parse1_();
	}
//	<1_> ::= K_ADD <1>
//	<1_> ::= K_SUB <2> <1_>
//	<1_> ::= e
	private static  void parse1_() throws Exception{
		//system.out.println("parse1_");
		Symbol links, rechts;
		switch(lookaheadKind) {
		case K_ADD:
			acceptIt();
			parse1();

			rechts = (Symbol)tempStack.pop();
			links = (Symbol)tempStack.pop();
			tempStack.push(new Exp2(K_ADD,links,rechts));
			break;
		case K_SUB:
			acceptIt();
			parse2();
			
			//sub
			rechts = (Symbol)tempStack.pop();
			links = (Symbol)tempStack.pop();
			tempStack.push(new Exp2(K_SUB,links,rechts));			
			parse1_();
			break;
		}
	}
//	<2> ::= <3> <2_>
	private static  void parse2() throws Exception{
		//system.out.println("parse2");
		parse3();
		parse2_();
	}
//	<2_> ::= K_MUL <2>
//	<2_> ::= K_DIV <3> <2_>
//	<2_> ::= e
	private static  void parse2_() throws Exception{
		//system.out.println("parse2_");
		Symbol links, rechts;
		switch(lookaheadKind) {
		case K_MUL:
			acceptIt();
		case K_BREAKET_OPEN:
		case K_0:
		case K_1:
		case K_2:
		case K_3:
		case K_4:
		case K_5:
		case K_6:
		case K_7:
		case K_8:
		case K_9:
		case K_PI:
		case K_E:
		case K_X:
		case K_Y:
		case K_ANS:
		case K_SQRT:
		case K_LOG10:
		case K_LOG2:
		case K_LN :
		case K_SIN:
		case K_COS:
		case K_TAN:
		case K_ASIN:
		case K_ACOS:
		case K_ATAN:
		case K_SINH:
		case K_COSH:
		case K_TANH:
		case K_ASINH:
		case K_ACOSH:
		case K_ATANH:
		case K_FAC:
		case K_PER:
		case K_COM:
		case K_ABS:
			parse2();
			rechts = (Symbol)tempStack.pop();
			links = (Symbol)tempStack.pop();
			tempStack.push(new Exp2(K_MUL,links,rechts));	
			break;
		case K_DIV:
			acceptIt();
			parse3();
			//div
			rechts = (Symbol)tempStack.pop();
			links = (Symbol)tempStack.pop();
			tempStack.push(new Exp2(K_DIV,links,rechts));	
			parse2_();
			break;
		}
	}
//	<3> ::= <4> <3_>
	private static  void parse3() throws Exception{
		//system.out.println("parse3");
		parse4();
		parse3_();
	}
	
//	<3_> ::= K_POWER <3>
//	<3_> ::= e
	private static  void parse3_() throws Exception{
		//system.out.println("parse3_");
		Symbol links, rechts;
		switch(lookaheadKind) {
		case K_POWER:
			acceptIt();
			parse3();
			rechts = (Symbol)tempStack.pop();
			links = (Symbol)tempStack.pop();
			tempStack.push(new Exp2(K_POWER,links,rechts));	
			break;
		}	
	}

//	<4> ::= K_ADD <4>
//	<4> ::= K_SUB <4>
//	<4> ::= <5>
	private static  void parse4() throws Exception{
		//system.out.println("parse4");
		switch(lookaheadKind) {
		case K_ADD:
			acceptIt();
			parse4();
			break;
		case K_SUB:
			acceptIt();				
			parse4();			
			Symbol rechts = (Symbol)tempStack.pop();
			tempStack.push(new Exp1(K_SUB,rechts));
			break;
		default:
			parse5();
			break;
		}		
	}
//	<5> ::= K_ANS
//	<5> ::= K_PI
//	<5> ::= K_E
//	<5> ::= K_X
//	<5> ::= K_BREAKET_OPEN <1> K_BREAKET_CLOSE
//	<5> ::= K_FUNCTION <1> K_BREAKET_CLOSE
//	<5> ::= <6>
	private static  void parse5() throws Exception{
		//system.out.println("parse5");
		switch(lookaheadKind) {
		case K_ANS:
			acceptIt();
			tempStack.push(new Num(XCalc.history.ANS()));
			break;
		case K_PI:
			acceptIt();				
			tempStack.push(new Num(Real.PI));
			break;
		case K_E:
			acceptIt();	
			tempStack.push(new Num(Real.E));
			break;
		case K_X:
			acceptIt();
			tempStack.push(Num.getXVar());
			break;
		case K_Y:
			acceptIt();
			tempStack.push(Num.getYVar());
			break;
		case K_BREAKET_OPEN:
			acceptIt();	
			parse1();
			if(lookaheadKind==K_BREAKET_CLOSE) 
				acceptIt();
			break;		
		case K_SQRT:
		case K_LOG10:
		case K_LOG2:
		case K_LN :
		case K_SIN:
		case K_COS:
		case K_TAN:
		case K_ASIN:
		case K_ACOS:
		case K_ATAN:
		case K_SINH:
		case K_COSH:
		case K_TANH:
		case K_ASINH:
		case K_ACOSH:
		case K_ATANH:
		case K_FAC:		
		case K_ABS:
			final int funcType = lookaheadKind;
			acceptIt();	
			parse1();
			if(lookaheadKind==K_BREAKET_CLOSE) 
				acceptIt();
			//calculate function
			Symbol rechts = (Symbol)tempStack.pop();
			tempStack.push(new Exp1(funcType,rechts));		
			break;
		case K_PER:
		case K_COM:
			final int f = lookaheadKind;
			acceptIt();	
			parse1();
			if(lookaheadKind==K_SEMI) 
				acceptIt();
			parse1();
			if(lookaheadKind==K_BREAKET_CLOSE) 
				acceptIt();
			
			//calculate function
			final Symbol b = (Symbol)tempStack.pop();
			final Symbol a = (Symbol)tempStack.pop();
			tempStack.push(new Exp2(f,a,b));
		break;
		default:
			parse6();
			break;
		}	
	}
//	<6> ::= K_NUMBER <6>
//	<6> ::= K_POINT <6_>
//	<6_> ::= K_NUMBER <6_>
//  <6_> ::= e
	private static  void parse6() throws Exception{
		//system.out.println("parse6");
		StringBuffer sb = new StringBuffer();
		boolean g = lookaheadKind<10;
		while(lookaheadKind<10){
			sb.append(lookaheadValue);
			acceptIt();
		}
	
		if(lookaheadKind==K_POINT){			
			sb.append(lookaheadValue);
			acceptIt();
			g = g || (lookaheadKind<10);
			while(lookaheadKind<10){				
				sb.append(lookaheadValue);
				acceptIt();
			}
		}		
		if(!g){
			throw new Exception("Expect a number");
		}	
		tempStack.push(new Num(new Real(sb.toString())));		
	}
}