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/*
* Copyright (C) 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ResultType_h
#define ResultType_h
namespace JSC {
struct ResultType {
friend struct OperandTypes;
typedef char Type;
static const Type TypeInt32 = 1;
static const Type TypeMaybeNumber = 0x04;
static const Type TypeMaybeString = 0x08;
static const Type TypeMaybeNull = 0x10;
static const Type TypeMaybeBool = 0x20;
static const Type TypeMaybeOther = 0x40;
static const Type TypeBits = TypeMaybeNumber | TypeMaybeString | TypeMaybeNull | TypeMaybeBool | TypeMaybeOther;
explicit ResultType(Type type)
: m_type(type)
{
}
bool isInt32()
{
return m_type & TypeInt32;
}
bool definitelyIsNumber()
{
return (m_type & TypeBits) == TypeMaybeNumber;
}
bool definitelyIsString()
{
return (m_type & TypeBits) == TypeMaybeString;
}
bool definitelyIsBoolean()
{
return (m_type & TypeBits) == TypeMaybeBool;
}
bool mightBeNumber()
{
return m_type & TypeMaybeNumber;
}
bool isNotNumber()
{
return !mightBeNumber();
}
static ResultType nullType()
{
return ResultType(TypeMaybeNull);
}
static ResultType booleanType()
{
return ResultType(TypeMaybeBool);
}
static ResultType numberType()
{
return ResultType(TypeMaybeNumber);
}
static ResultType numberTypeIsInt32()
{
return ResultType(TypeInt32 | TypeMaybeNumber);
}
static ResultType stringOrNumberType()
{
return ResultType(TypeMaybeNumber | TypeMaybeString);
}
static ResultType stringType()
{
return ResultType(TypeMaybeString);
}
static ResultType unknownType()
{
return ResultType(TypeBits);
}
static ResultType forAdd(ResultType op1, ResultType op2)
{
if (op1.definitelyIsNumber() && op2.definitelyIsNumber())
return numberType();
if (op1.definitelyIsString() || op2.definitelyIsString())
return stringType();
return stringOrNumberType();
}
// Unlike in C, a logical op produces the value of the
// last expression evaluated (and not true or false).
static ResultType forLogicalOp(ResultType op1, ResultType op2)
{
if (op1.definitelyIsBoolean() && op2.definitelyIsBoolean())
return booleanType();
if (op1.definitelyIsNumber() && op2.definitelyIsNumber())
return numberType();
if (op1.definitelyIsString() && op2.definitelyIsString())
return stringType();
return unknownType();
}
static ResultType forBitOp()
{
return numberTypeIsInt32();
}
private:
Type m_type;
};
struct OperandTypes
{
OperandTypes(ResultType first = ResultType::unknownType(), ResultType second = ResultType::unknownType())
{
// We have to initialize one of the int to ensure that
// the entire struct is initialized.
m_u.i = 0;
m_u.rds.first = first.m_type;
m_u.rds.second = second.m_type;
}
union {
struct {
ResultType::Type first;
ResultType::Type second;
} rds;
int i;
} m_u;
ResultType first()
{
return ResultType(m_u.rds.first);
}
ResultType second()
{
return ResultType(m_u.rds.second);
}
int toInt()
{
return m_u.i;
}
static OperandTypes fromInt(int value)
{
OperandTypes types;
types.m_u.i = value;
return types;
}
};
} // namespace JSC
#endif // ResultType_h