mathexpr.hh revision 11527
1/* 2 * Copyright (c) 2016 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions are 16 * met: redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer; 18 * redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution; 21 * neither the name of the copyright holders nor the names of its 22 * contributors may be used to endorse or promote products derived from 23 * this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * Authors: David Guillen Fandos 38 */ 39 40#ifndef __SIM_MATHEXPR_HH__ 41#define __SIM_MATHEXPR_HH__ 42 43#include <algorithm> 44#include <string> 45 46class MathExpr { 47 public: 48 49 MathExpr(std::string expr); 50 51 typedef std::function<double(std::string)> EvalCallback; 52 53 /** 54 * Prints an ASCII representation of the expression tree 55 * 56 * @return A string containing the ASCII representation of the expression 57 */ 58 std::string toStr() const { return toStr(root, ""); } 59 60 /** 61 * Evaluates the expression 62 * 63 * @param fn A callback funcion to evaluate variables 64 * 65 * @return The value for this expression 66 */ 67 double eval(EvalCallback fn) const { return eval(root, fn); } 68 69 private: 70 enum Operator { 71 bAdd, bSub, bMul, bDiv, bPow, uNeg, sValue, sVariable, nInvalid 72 }; 73 74 // Match operators 75 const int MAX_PRIO = 4; 76 typedef double (*binOp)(double, double); 77 struct OpSearch { 78 bool binary; 79 Operator op; 80 int priority; 81 char c; 82 binOp fn; 83 }; 84 85 /** Operator list */ 86 std::array<OpSearch, uNeg + 1> ops; 87 88 class Node { 89 public: 90 Node() : op(nInvalid), l(0), r(0), value(0) {} 91 std::string toStr() const { 92 const char opStr[] = {'+', '-', '*', '/', '^', '-'}; 93 switch (op) { 94 case nInvalid: 95 return "INVALID"; 96 case sVariable: 97 return variable; 98 case sValue: 99 return std::to_string(value); 100 default: 101 return std::string(1, opStr[op]); 102 }; 103 } 104 105 Operator op; 106 Node *l, *r; 107 double value; 108 std::string variable; 109 }; 110 111 /** Root node */ 112 Node * root; 113 114 /** Parse and create nodes from string */ 115 Node *parse(std::string expr); 116 117 /** Print tree as string */ 118 std::string toStr(Node *n, std::string prefix) const; 119 120 /** Eval a node */ 121 double eval(const Node *n, EvalCallback fn) const; 122}; 123 124#endif 125 126 127