value.cpp

来自「konqueror3 embedded版本, KDE环境下的当家浏览器的嵌入式版」· C++ 代码 · 共 413 行

// -*- c-basic-offset: 2 -*-
/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 1999-2001 Harri Porten ([e-mail])
 *  Copyright (C) 2001 Peter Kelly ([e-mail])
 *  Copyright (C) 2003 Apple Computer, Inc.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include "value.h"
#include "object.h"
#include "types.h"
#include "interpreter.h"

#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>

#include "internal.h"
#include "collector.h"
#include "operations.h"
#include "error_object.h"
#include "nodes.h"
#include "simple_number.h"

using namespace KJS;

// ----------------------------- ValueImp -------------------------------------

ValueImp::ValueImp() :
  refcount(0),
  // Tell the garbage collector that this memory block corresponds to a real object now
  _flags(VI_CREATED)
{
  //fprintf(stderr,"ValueImp::ValueImp %p\n",(void*)this);
}

ValueImp::~ValueImp()
{
  //fprintf(stderr,"ValueImp::~ValueImp %p\n",(void*)this);
  _flags |= VI_DESTRUCTED;
}

void ValueImp::mark()
{
  //fprintf(stderr,"ValueImp::mark %p\n",(void*)this);
  _flags |= VI_MARKED;
}

bool ValueImp::marked() const
{
  // Simple numbers are always considered marked.
  return SimpleNumber::is(this) || (_flags & VI_MARKED);
}

void ValueImp::setGcAllowed()
{
  //fprintf(stderr,"ValueImp::setGcAllowed %p\n",(void*)this);
  // simple numbers are never seen by the collector so setting this
  // flag is irrelevant
  if (!SimpleNumber::is(this))
    _flags |= VI_GCALLOWED;
}

void* ValueImp::operator new(size_t s)
{
  return Collector::allocate(s);
}

void ValueImp::operator delete(void*)
{
  // Do nothing. So far.
}

bool ValueImp::toUInt32(unsigned&) const
{
  return false;
}

// ECMA 9.4
int ValueImp::toInteger(ExecState *exec) const
{
  unsigned i;
  if (dispatchToUInt32(i))
    return static_cast<int>(i);
  double d = roundValue(exec, Value(const_cast<ValueImp*>(this)));
  if (isInf(d))
    return INT_MAX;
  return static_cast<int>(d);
}

int ValueImp::toInt32(ExecState *exec) const
{
  unsigned i;
  if (dispatchToUInt32(i))
    return (int)i;

  double d = roundValue(exec, Value(const_cast<ValueImp*>(this)));
  if (isNaN(d) || isInf(d) || d == 0.0)
    return 0;
  double d32 = fmod(d, D32);

  //Make sure we use the positive remainder. This matters since this may be
  //less than MIN_INT (but still < 2^32), and we don't want the cast to clamp.
  if (d32 < 0)
    d32 += D32;

  if (d32 >= D32 / 2.0)
    d32 -= D32;

  return static_cast<int>(d32);
}

unsigned int ValueImp::toUInt32(ExecState *exec) const
{
  unsigned i;
  if (dispatchToUInt32(i))
    return i;

  double d = roundValue(exec, Value(const_cast<ValueImp*>(this)));
  if (isNaN(d) || isInf(d) || d == 0.0)
    return 0;
  double d32 = fmod(d, D32);

  if (d32 < 0)
    d32 += D32;

  //6.3.1.4 Real floating and integer
  // 50) The remaindering operation performed when a value of integer type is
  //   converted to unsigned type need not be performed when a value of real
  //   floating type is converted to unsigned type. Thus, the range of
  //   portable real floating values is (-1, Utype_MAX+1).
  return static_cast<unsigned int>(d32);
}

unsigned short ValueImp::toUInt16(ExecState *exec) const
{
  unsigned i;
  if (dispatchToUInt32(i))
    return (unsigned short)i;

  double d = roundValue(exec, Value(const_cast<ValueImp*>(this)));
  double d16 = fmod(d, D16);

  // look at toUInt32 to see why this is necesary
  int t_int = static_cast<int>(d16);
  return static_cast<unsigned short>(t_int);
}

// Dispatchers for virtual functions, to special-case simple numbers which
// won't be real pointers.

Type ValueImp::dispatchType() const
{
  if (SimpleNumber::is(this))
    return NumberType;
  return type();
}

Value ValueImp::dispatchToPrimitive(ExecState *exec, Type preferredType) const
{
  if (SimpleNumber::is(this))
    return Value(const_cast<ValueImp *>(this));
  return toPrimitive(exec, preferredType);
}

bool ValueImp::dispatchToBoolean(ExecState *exec) const
{
  if (SimpleNumber::is(this))
    return SimpleNumber::value(this);
  return toBoolean(exec);
}

double ValueImp::dispatchToNumber(ExecState *exec) const
{
  if (SimpleNumber::is(this))
    return SimpleNumber::value(this);
  return toNumber(exec);
}

UString ValueImp::dispatchToString(ExecState *exec) const
{
  if (SimpleNumber::is(this))
    return UString::from(SimpleNumber::value(this));
  return toString(exec);
}

Object ValueImp::dispatchToObject(ExecState *exec) const
{
  if (SimpleNumber::is(this))
    return static_cast<const NumberImp *>(this)->NumberImp::toObject(exec);
  return toObject(exec);
}

bool ValueImp::dispatchToUInt32(unsigned& result) const
{
  if (SimpleNumber::is(this)) {
    long i = SimpleNumber::value(this);
    if (i < 0)
      return false;
    result = (unsigned)i;
    return true;
  }
  return toUInt32(result);
}

// ------------------------------ Value ----------------------------------------

Value::Value(ValueImp *v)
{
  rep = v;
#ifdef DEBUG_COLLECTOR
  assert (!(rep && !SimpleNumber::is(rep) && *((uint32_t *)rep) == 0 ));
  assert (!(rep && !SimpleNumber::is(rep) && rep->_flags & ValueImp::VI_MARKED));
#endif
  if (v)
  {
    v->ref();
    //fprintf(stderr, "Value::Value(%p) imp=%p ref=%d\n", this, rep, rep->refcount);
    v->setGcAllowed();
  }
}

Value::Value(const Value &v)
{
  rep = v.imp();
#ifdef DEBUG_COLLECTOR
  assert (!(rep && !SimpleNumber::is(rep) && *((uint32_t *)rep) == 0 ));
  assert (!(rep && !SimpleNumber::is(rep) && rep->_flags & ValueImp::VI_MARKED));
#endif
  if (rep)
  {
    rep->ref();
    //fprintf(stderr, "Value::Value(%p)(copying %p) imp=%p ref=%d\n", this, &v, rep, rep->refcount);
  }
}

Value::~Value()
{
  if (rep)
  {
    rep->deref();
    //fprintf(stderr, "Value::~Value(%p) imp=%p ref=%d\n", this, rep, rep->refcount);
  }
}

Value& Value::operator=(const Value &v)
{
  ValueImp *tmpRep = v.imp();

  //Avoid the destruction of the object underneath us by
  //incrementing the reference on it first
  if (tmpRep) {
    tmpRep->ref();
    //fprintf(stderr, "Value::operator=(%p)(copying %p) imp=%p ref=%d\n", this, &v, tmpRep, tmpRep->refcount);
  }

  if (rep) {
    rep->deref();
    //fprintf(stderr, "Value::operator=(%p)(copying %p) old imp=%p ref=%d\n", this, &v, rep, rep->refcount);
  }
  rep = tmpRep;

  return *this;
}

// ------------------------------ Undefined ------------------------------------

Undefined::Undefined() : Value(UndefinedImp::staticUndefined)
{
}

Undefined Undefined::dynamicCast(const Value &v)
{
  if (!v.isValid() || v.type() != UndefinedType)
    return Undefined(0);

  return Undefined();
}

// ------------------------------ Null -----------------------------------------

Null::Null() : Value(NullImp::staticNull)
{
}

Null Null::dynamicCast(const Value &v)
{
  if (!v.isValid() || v.type() != NullType)
    return Null(0);

  return Null();
}

// ------------------------------ Boolean --------------------------------------

Boolean::Boolean(bool b)
  : Value(b ? BooleanImp::staticTrue : BooleanImp::staticFalse)
{
}

bool Boolean::value() const
{
  assert(rep);
  return ((BooleanImp*)rep)->value();
}

Boolean Boolean::dynamicCast(const Value &v)
{
  if (!v.isValid() || v.type() != BooleanType)
    return static_cast<BooleanImp*>(0);

  return static_cast<BooleanImp*>(v.imp());
}

// ------------------------------ String ---------------------------------------

String::String(const UString &s) : Value(new StringImp(s))
{
#ifndef NDEBUG
  if (s.isNull())
    fprintf(stderr, "WARNING: KJS::String constructed from null string\n");
#endif
}

UString String::value() const
{
  assert(rep);
  return ((StringImp*)rep)->value();
}

String String::dynamicCast(const Value &v)
{
  if (!v.isValid() || v.type() != StringType)
    return String(0);

  return String(static_cast<StringImp*>(v.imp()));
}

// ------------------------------ Number ---------------------------------------

Number::Number(int i)
  : Value(SimpleNumber::fits(i) ? SimpleNumber::make(i) : new NumberImp(static_cast<double>(i))) { }

Number::Number(unsigned int u)
  : Value(SimpleNumber::fits(u) ? SimpleNumber::make(u) : new NumberImp(static_cast<double>(u))) { }

Number::Number(double d)
#if defined(__alpha) && !defined(_IEEE_FP)
  // check for NaN first if we werent't compiled with -mieee on Alpha
 : Value(KJS::isNaN(d) ? NumberImp::staticNaN : (SimpleNumber::fits(d) ? SimpleNumber::make((long)d) : new NumberImp(d))) { }
#else
 : Value(SimpleNumber::fits(d) ? SimpleNumber::make((long)d) : (KJS::isNaN(d) ? NumberImp::staticNaN : new NumberImp(d))) { }
#endif

Number::Number(long int l)
  : Value(SimpleNumber::fits(l) ? SimpleNumber::make(l) : new NumberImp(static_cast<double>(l))) { }

Number::Number(long unsigned int l)
  : Value(SimpleNumber::fits(l) ? SimpleNumber::make(l) : new NumberImp(static_cast<double>(l))) { }

Number Number::dynamicCast(const Value &v)
{
  if (!v.isValid() || v.type() != NumberType)
    return Number((NumberImp*)0);

  return Number(static_cast<NumberImp*>(v.imp()));
}

double Number::value() const
{
  if (SimpleNumber::is(rep))
    return (double)SimpleNumber::value(rep);
  assert(rep);
  return ((NumberImp*)rep)->value();
}

int Number::intValue() const
{
  if (SimpleNumber::is(rep))
    return SimpleNumber::value(rep);
  return (int)((NumberImp*)rep)->value();
}

bool Number::isNaN() const
{
  return rep == NumberImp::staticNaN;
}

bool Number::isInf() const
{
  if (SimpleNumber::is(rep))
    return false;
  return KJS::isInf(((NumberImp*)rep)->value());
}