1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef CONSTANT_EXPRESSION_H_ 18 19 #define CONSTANT_EXPRESSION_H_ 20 21 #include <android-base/macros.h> 22 #include <string> 23 #include "ScalarType.h" 24 25 namespace android { 26 27 /** 28 * A constant expression is represented by a tree. 29 */ 30 struct ConstantExpression { 31 32 enum ConstExprType { 33 kConstExprLiteral, 34 kConstExprUnary, 35 kConstExprBinary, 36 kConstExprTernary 37 }; 38 39 /* Default constructor. */ 40 ConstantExpression(); 41 /* Copy constructor. */ 42 ConstantExpression(const ConstantExpression& other); 43 /* Copy constructor, with the expr overriden. */ 44 ConstantExpression(const ConstantExpression& other, std::string expr); 45 /* Literals */ 46 ConstantExpression(const char *value); 47 /* binary operations */ 48 ConstantExpression(const ConstantExpression *value1, 49 const char *op, const ConstantExpression* value2); 50 /* unary operations */ 51 ConstantExpression(const char *op, const ConstantExpression *value); 52 /* ternary ?: */ 53 ConstantExpression(const ConstantExpression *cond, 54 const ConstantExpression *trueVal, 55 const ConstantExpression *falseVal); 56 57 static ConstantExpression Zero(ScalarType::Kind kind); 58 static ConstantExpression One(ScalarType::Kind kind); 59 static ConstantExpression ValueOf(ScalarType::Kind kind, uint64_t value); 60 61 /* Evaluated result in a string form. */ 62 std::string value() const; 63 /* Evaluated result in a string form. */ 64 std::string cppValue() const; 65 /* Evaluated result in a string form. */ 66 std::string javaValue() const; 67 /* Evaluated result in a string form, with given contextual kind. */ 68 std::string value(ScalarType::Kind castKind) const; 69 /* Evaluated result in a string form, with given contextual kind. */ 70 std::string cppValue(ScalarType::Kind castKind) const; 71 /* Evaluated result in a string form, with given contextual kind. */ 72 std::string javaValue(ScalarType::Kind castKind) const; 73 /* Original expression with type. */ 74 const std::string &description() const; 75 /* See mTrivialDescription */ 76 bool descriptionIsTrivial() const; 77 /* Return a ConstantExpression that is 1 plus the original. */ 78 ConstantExpression addOne() const; 79 /* Assignment operator. */ 80 ConstantExpression& operator=(const ConstantExpression& other); 81 82 size_t castSizeT() const; 83 84 private: 85 /* The formatted expression. */ 86 std::string mExpr; 87 /* The type of the expression. Hints on its original form. */ 88 ConstExprType mType; 89 /* The kind of the result value. */ 90 ScalarType::Kind mValueKind; 91 /* The stored result value. */ 92 uint64_t mValue; 93 /* true if description() does not offer more information than value(). */ 94 bool mTrivialDescription = false; 95 96 /* 97 * Helper function for all cpp/javaValue methods. 98 * Returns a plain string (without any prefixes or suffixes, just the 99 * digits) converted from mValue. 100 */ 101 std::string rawValue(ScalarType::Kind castKind) const; 102 /* Trim unnecessary information. Only mValue and mValueKind is kept. */ 103 ConstantExpression &toLiteral(); 104 105 /* 106 * Return the value casted to the given type. 107 * First cast it according to mValueKind, then cast it to T. 108 * Assumes !containsIdentifiers() 109 */ 110 template <typename T> T cast() const; 111 }; 112 113 } // namespace android 114 115 #endif // CONSTANT_EXPRESSION_H_ 116
