From f4c20290509d7ed3a8fd5304577e7a4cc0b9d974 Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Tue, 3 Apr 2007 03:49:53 +0000
Subject: Ok, no code is left in src, it's all in src/old.  We'll gradually
 move code back into src as it's fixed and re-org'd.  This includes tests,
 which, I may write a unit test system into libbu++ just to make my life
 easier.

---
 src/old/formula.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/old/formula.h

(limited to 'src/old/formula.h')

diff --git a/src/old/formula.h b/src/old/formula.h
new file mode 100644
index 0000000..939eb09
--- /dev/null
+++ b/src/old/formula.h
@@ -0,0 +1,77 @@
+#ifndef FORMULA_H
+#define FORMULA_H
+
+#include <stdint.h>
+
+#include <math.h>
+#include <stack>
+#include "sbuffer.h"
+
+#include "exceptionbase.h"
+#include "hash.h"
+
+subExceptionDecl( ParseException );
+
+/**
+ * Implements a very simple formula parser that allows use of variables and
+ * custom functions.  This is based on a simple calculator-type parser that
+ * executes as it processes, accounting for operator precedence and grouping.
+ */
+class Formula
+{
+public:
+	Formula();
+	virtual ~Formula();
+
+	double run( char *sFormula );
+
+	typedef Hash<std::string, double> varHash;
+	varHash hVars;
+
+	typedef struct Func
+	{
+		double operator()( double x )
+		{
+			return 0.0;
+		}
+	} Func;
+
+	typedef Hash<std::string, Func> funcHash;
+	funcHash hFunc;
+
+	typedef struct FuncSin : Func
+	{
+		double operator()( double x )
+		{
+			return sin( x );
+		}
+	} FuncSin;
+
+private:
+	enum
+	{
+		symEOS,
+		symAdd,
+		symSubtract,
+		symMultiply,
+		symDivide,
+		symOpenParen,
+		symCloseParen,
+		symNumber,
+		symVariable,
+		symExponent,
+		symModulus
+	};
+
+	typedef uint8_t symType;
+
+	std::stack<symType> sOper;
+	std::stack<double> sValue;
+
+private:
+	symType getPrec( symType nOper );
+	symType nextToken( char **sBuf );
+	void reduce( bool bCloseParen = false );
+};
+
+#endif
-- 
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