1 files changed, 430 insertions, 0 deletions

diff --git a/src/stable/formula.h b/src/stable/formula.h
new file mode 100644
index 0000000..687e6c3
--- /dev/null
+++ b/src/stable/formula.h
@@ -0,0 +1,430 @@
+/*
+ * Copyright (C) 2007-2011 Xagasoft, All rights reserved.
+ *
+ * This file is part of the libbu++ library and is released under the
+ * terms of the license contained in the file LICENSE.
+ */
+
+#ifndef FORMULA_H
+#define FORMULA_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <math.h>
+//#include "sbuffer.h"
+
+#include "bu/stack.h"
+#include "bu/exceptionbase.h"
+#include "bu/hash.h"
+#include "bu/string.h"
+
+namespace Bu
+{
+        subExceptionDecl( FormulaException );
+        /**
+         * 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.
+         *
+         * prec = precision, a type to use for all math (except binary ops)
+         * bin = binary type, a type to hard cast all data to for binary ops
+         */
+        template<typename prec, typename bin=uint32_t>
+        class Formula
+        {
+        public:
+                class Func
+                {
+                public:
+                        virtual prec operator()( prec )=0;
+                };
+
+                typedef Hash<Bu::String, prec> varHash;
+                typedef Hash<Bu::String, Func *> funcHash;
+
+                Formula()
+                {
+                }
+
+                virtual ~Formula()
+                {
+                        for( typename funcHash::iterator i = hFunc.begin();
+                                 i != hFunc.end(); i++ )
+                        {
+                                delete (*i);
+                        }
+                }
+
+                prec run( const Bu::String &sFormulaSrc )
+                {
+                        if( sFormulaSrc.isEmpty() )
+                                throw FormulaException("Empty formula, nothing to do.");
+                        try
+                        {
+                                const char *sFormula = sFormulaSrc.getStr();
+                                for(;;)
+                                {
+                                        uint8_t tNum = nextToken( &sFormula );
+                                        if( tNum == symSubtract )
+                                        {
+                                                sOper.push( symNegate );
+                                                continue;
+                                        }
+                                        else if( tNum == symNot )
+                                        {
+                                                sOper.push( symNot );
+                                                continue;
+                                        }
+                                        else if( tNum == symOpenParen )
+                                        {
+                                                sOper.push( tNum );
+                                                continue;
+                                        }
+                                        else if( tNum == symFunction )
+                                        {
+                                                sOper.push( symFunction );
+                                                continue;
+                                        }
+                                        else if( tNum == symEOS )
+                                        {
+                                                throw Bu::FormulaException(
+                                                        "Cannot end with an operator.");
+                                        }
+
+                        oppart: uint8_t tOpr = nextToken( &sFormula );
+                                        if( tOpr == symEOS )
+                                        {
+                                                reduce();
+                                                prec ret = sValue.top();
+                                                sValue.clear();
+                                                sFunc.clear();
+                                                sOper.clear();
+                                                return ret;
+                                        }
+                                        if( !sOper.isEmpty() && getPrec( sOper.top() ) >
+                                                getPrec( tOpr ) )
+                                        {
+                                                reduce();
+                                        }
+                                        if( tOpr != symCloseParen )
+                                        {
+                                                sOper.push( tOpr );
+                                        }
+                                        else
+                                        {
+                                                reduce( true );
+                                                goto oppart;
+                                        }
+                                }
+                        }
+                        catch( ... )
+                        {
+                                sValue.clear();
+                                sFunc.clear();
+                                sOper.clear();
+                                throw;
+                        }
+                }
+
+                varHash hVars;
+                funcHash hFunc;
+
+        private:
+                enum
+                {
+                        symEOS,
+                        symAdd,
+                        symSubtract,
+                        symMultiply,
+                        symDivide,
+                        symOpenParen,
+                        symCloseParen,
+                        symNumber,
+                        symVariable,
+                        symFunction,
+                        symExponent,
+                        symNegate,
+                        symModulus,
+
+                        symAnd,
+                        symOr,
+                        symXor,
+                        symNot
+                };
+
+                typedef uint8_t symType;
+
+                Bu::Stack<symType> sOper;
+                Bu::Stack<prec> sValue;
+                Bu::Stack<Bu::String> sFunc;
+
+        private:
+                symType getPrec( symType nOper )
+                {
+                        switch( nOper )
+                        {
+                                case symNumber:
+                                case symVariable:
+                                case symOpenParen:
+                                case symCloseParen:
+                                        return 0;
+
+                                case symAdd:
+                                case symSubtract:
+                                        return 1;
+
+                                case symMultiply:
+                                case symDivide:
+                                case symModulus:
+                                        return 2;
+
+                                case symAnd:
+                                case symOr:
+                                case symXor:
+                                        return 2;
+
+                                case symExponent:
+                                case symNot:
+                                case symNegate:
+                                case symFunction:
+                                        return 3;
+
+                                default:
+                                        return 0;
+                        }
+                }
+
+                symType nextToken( const char **sBuf )
+                {
+                        for(;;)
+                        {
+                                char cbuf = **sBuf;
+                                ++(*sBuf);
+                                switch( cbuf )
+                                {
+                                        case '+':
+                                                return symAdd;
+
+                                        case '-':
+                                                return symSubtract;
+
+                                        case '*':
+                                                return symMultiply;
+
+                                        case '/':
+                                                return symDivide;
+
+                                        case '^':
+                                                return symExponent;
+
+                                        case '%':
+                                                return symModulus;
+
+                                        case '(':
+                                                return symOpenParen;
+
+                                        case ')':
+                                                return symCloseParen;
+
+                                        case '|':
+                                                return symOr;
+
+                                        case '&':
+                                                return symAnd;
+
+                                        case '#':
+                                                return symXor;
+
+                                        case '~':
+                                                return symNot;
+
+                                        case ' ':
+                                        case '\t':
+                                        case '\n':
+                                        case '\r':
+                                                break;
+
+                                        case '\0':
+                                                return symEOS;
+
+                                        default:
+                                                if( cbuf == '.' || (cbuf >= '0' && cbuf <= '9') )
+                                                {
+                                                        char num[50]={cbuf};
+                                                        int nPos = 1;
+                                                        bool bDot = false;
+
+                                                        for(;;)
+                                                        {
+                                                                cbuf = **sBuf;
+                                                                if( cbuf == '.' )
+                                                                {
+                                                                        if( bDot == false )
+                                                                                bDot = true;
+                                                                        else
+                                                                                throw FormulaException(
+                                                                                        "Numbers cannot have more than one "
+                                                                                        ". in them."
+                                                                                        );
+                                                                }
+                                                                if( cbuf == '.' ||
+                                                                        (cbuf >= '0' && cbuf <= '9') )
+                                                                {
+                                                                        num[nPos++] = cbuf;
+                                                                }
+                                                                else
+                                                                {
+                                                                        num[nPos] = '\0';
+                                                                        sValue.push(
+                                                                                static_cast<prec>(
+                                                                                        strtod( num, NULL )
+                                                                                        )
+                                                                                );
+                                                                        return symNumber;
+                                                                }
+                                                                ++(*sBuf);
+                                                        }
+                                                }
+                                                else if( (cbuf >= 'a' && cbuf <= 'z') || 
+                                                                 (cbuf >= 'A' && cbuf <= 'Z') ||
+                                                                 (cbuf == '_') )
+                                                {
+                                                        char tok[50]={cbuf};
+                                                        int nPos = 1;
+
+                                                        for(;;)
+                                                        {
+                                                                cbuf = **sBuf;
+                                                                if( (cbuf >= 'a' && cbuf <= 'z') || 
+                                                                        (cbuf >= 'A' && cbuf <= 'Z') ||
+                                                                        (cbuf >= '0' && cbuf <= '9') ||
+                                                                        cbuf == '_' || cbuf == '.' || cbuf == ':' )
+                                                                {
+                                                                        tok[nPos++] = cbuf;
+                                                                }
+                                                                else
+                                                                {
+                                                                        tok[nPos] = '\0';
+                                                                        if( hVars.has( tok ) )
+                                                                        {
+                                                                                sValue.push( hVars[tok] );
+                                                                                return symNumber;
+                                                                        }
+                                                                        else if( hFunc.has( tok ) )
+                                                                        {
+                                                                                sFunc.push( tok );
+                                                                                return symFunction;
+                                                                        }
+                                                                        else
+                                                                        {
+                                                                                throw FormulaException(
+                                                                                        "No variable or function named "
+                                                                                        "\"%s\" exists.",
+                                                                                        tok
+                                                                                        );
+                                                                        }
+                                                                }
+                                                                ++(*sBuf);
+                                                        }
+                                                }
+                                                break;
+                                }
+                        }
+                }
+
+                void reduce( bool bCloseParen = false )
+                {
+                        while( !sOper.isEmpty() )
+                        {
+                                uint8_t nOpr = sOper.top();
+                                if( nOpr == symOpenParen )
+                                {
+                                        if( bCloseParen == true )
+                                                sOper.pop();
+                                        return;
+                                }
+                                sOper.pop();
+
+                                prec dTop = sValue.top();
+                                sValue.pop();
+
+                                switch( nOpr )
+                                {
+                                        case symAdd:
+                                                sValue.top() += dTop;
+                                                break;
+
+                                        case symSubtract:
+                                                sValue.top() -= dTop;
+                                                break;
+
+                                        case symMultiply:
+                                                sValue.top() *= dTop;
+                                                break;
+
+                                        case symDivide:
+                                                sValue.top() /= dTop;
+                                                break;
+
+                                        case symExponent:
+                                                sValue.top() = static_cast<prec>(
+                                                                pow( sValue.top(), dTop )
+                                                        );
+                                                break;
+
+                                        case symModulus:
+                                                sValue.top() = static_cast<prec>(
+                                                                fmod( sValue.top(), dTop )
+                                                        );
+                                                break;
+
+                                        case symOr:
+                                                sValue.top() = static_cast<prec>(
+                                                                static_cast<bin>(sValue.top()) |
+                                                                static_cast<bin>(dTop)
+                                                        );
+                                                break;
+                                        
+                                        case symAnd:
+                                                sValue.top() = static_cast<prec>(
+                                                                static_cast<bin>(sValue.top()) &
+                                                                static_cast<bin>(dTop)
+                                                        );
+                                                break;
+                                        
+                                        case symXor:
+                                                sValue.top() = static_cast<prec>(
+                                                                static_cast<bin>(sValue.top()) ^
+                                                                static_cast<bin>(dTop)
+                                                        );
+                                                break;
+
+                                        case symFunction:
+                                                sValue.push( (*hFunc.get( sFunc.pop() ))( dTop ) );
+                                                break;
+
+                                        case symNegate:
+                                                sValue.push( -dTop );
+                                                break;
+
+                                        case symNot:
+                                                sValue.push( static_cast<prec>(
+                                                                ~static_cast<bin>(dTop)
+                                                        ) );
+                                                break;
+                                }
+                        }
+
+                        if( bCloseParen == true )
+                        {
+                                throw FormulaException(
+                                        "Close-paren found without matching open-paren."
+                                        );
+                        }
+                }
+        };
+}
+
+#endif