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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef CONSTANT_EXPRESSION_H_
#define CONSTANT_EXPRESSION_H_
#include <android-base/macros.h>
#include <string>
#include "ScalarType.h"
namespace android {
/**
* A constant expression is represented by a tree.
*/
struct ConstantExpression {
enum ConstExprType {
kConstExprLiteral,
kConstExprUnary,
kConstExprBinary,
kConstExprTernary
};
/* Default constructor. */
ConstantExpression();
/* Copy constructor. */
ConstantExpression(const ConstantExpression& other);
/* Copy constructor, with the expr overriden. */
ConstantExpression(const ConstantExpression& other, std::string expr);
/* Literals */
ConstantExpression(const char *value);
/* binary operations */
ConstantExpression(const ConstantExpression *value1,
const char *op, const ConstantExpression* value2);
/* unary operations */
ConstantExpression(const char *op, const ConstantExpression *value);
/* ternary ?: */
ConstantExpression(const ConstantExpression *cond,
const ConstantExpression *trueVal,
const ConstantExpression *falseVal);
static ConstantExpression Zero(ScalarType::Kind kind);
static ConstantExpression One(ScalarType::Kind kind);
/* Evaluated result in a string form. */
std::string value() const;
/* Evaluated result in a string form. */
std::string cppValue() const;
/* Evaluated result in a string form. */
std::string javaValue() const;
/* Evaluated result in a string form, with given contextual kind. */
std::string cppValue(ScalarType::Kind castKind) const;
/* Evaluated result in a string form, with given contextual kind. */
std::string javaValue(ScalarType::Kind castKind) const;
/* Original expression with type. */
const std::string &description() const;
/* See mTrivialDescription */
bool descriptionIsTrivial() const;
/* Return a ConstantExpression that is 1 plus the original. */
ConstantExpression addOne() const;
/* Assignment operator. */
ConstantExpression& operator=(const ConstantExpression& other);
size_t castSizeT() const;
private:
/* The formatted expression. */
std::string mExpr;
/* The type of the expression. Hints on its original form. */
ConstExprType mType;
/* The kind of the result value. */
ScalarType::Kind mValueKind;
/* The stored result value. */
uint64_t mValue;
/* true if description() does not offer more information than value(). */
bool mTrivialDescription = false;
/*
* Helper function for all cpp/javaValue methods.
* Returns a plain string (without any prefixes or suffixes, just the
* digits) converted from mValue.
*/
std::string rawValue(ScalarType::Kind castKind) const;
/* Trim unnecessary information. Only mValue and mValueKind is kept. */
ConstantExpression &toLiteral();
/*
* Return the value casted to the given type.
* First cast it according to mValueKind, then cast it to T.
* Assumes !containsIdentifiers()
*/
template <typename T> T cast() const;
};
} // namespace android
#endif // CONSTANT_EXPRESSION_H_