list.cpp
/*
* This file is part of the KDE libraries
* 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 "list.h"
#include "internal.h"
#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
#define DUMP_STATISTICS 0
namespace KJS {
// tunable parameters
const int poolSize = 32; // must be a power of 2
const int inlineValuesSize = 4;
// derived constants
const int poolSizeMask = poolSize - 1;
enum ListImpState { unusedInPool = 0, usedInPool, usedOnHeap, immortal };
struct ListImp : ListImpBase
{
ListImpState state;
ValueImp *values[inlineValuesSize];
int capacity;
ValueImp **overflow;
#if DUMP_STATISTICS
int sizeHighWaterMark;
#endif
};
static ListImp pool[poolSize];
static int poolCursor;
#if DUMP_STATISTICS
static int numLists;
static int numListsHighWaterMark;
static int listSizeHighWaterMark;
static int numListsDestroyed;
static int numListsBiggerThan[17];
struct ListStatisticsExitLogger { ~ListStatisticsExitLogger(); };
static ListStatisticsExitLogger logger;
ListStatisticsExitLogger::~ListStatisticsExitLogger()
{
printf("\nKJS::List statistics:\n\n");
printf("%d lists were allocated\n", numLists);
printf("%d lists was the high water mark\n", numListsHighWaterMark);
printf("largest list had %d elements\n", listSizeHighWaterMark);
if (numListsDestroyed) {
putc('\n', stdout);
for (int i = 0; i < 17; i++) {
printf("%.1f%% of the lists (%d) had more than %d element%s\n",
100.0 * numListsBiggerThan[i] / numListsDestroyed,
numListsBiggerThan[i],
i, i == 1 ? "" : "s");
}
putc('\n', stdout);
}
}
#endif
static inline ListImp *allocateListImp()
{
// Find a free one in the pool.
int c = poolCursor;
int i = c;
do {
ListImp *imp = &pool[i];
ListImpState s = imp->state;
i = (i + 1) & poolSizeMask;
if (s == unusedInPool) {
poolCursor = i;
imp->state = usedInPool;
return imp;
}
} while (i != c);
ListImp *imp = new ListImp;
imp->state = usedOnHeap;
return imp;
}
static inline void deallocateListImp(ListImp *imp)
{
if (imp->state == usedInPool)
imp->state = unusedInPool;
else
delete imp;
}
List::List() : _impBase(allocateListImp()), _needsMarking(false)
{
ListImp *imp = static_cast<ListImp *>(_impBase);
imp->size = 0;
imp->refCount = 1;
imp->capacity = 0;
imp->overflow = 0;
if (!_needsMarking) {
imp->valueRefCount = 1;
}
#if DUMP_STATISTICS
if (++numLists > numListsHighWaterMark)
numListsHighWaterMark = numLists;
imp->sizeHighWaterMark = 0;
#endif
}
List::List(bool needsMarking) : _impBase(allocateListImp()), _needsMarking(needsMarking)
{
ListImp *imp = static_cast<ListImp *>(_impBase);
imp->size = 0;
imp->refCount = 1;
imp->capacity = 0;
imp->overflow = 0;
if (!_needsMarking) {
imp->valueRefCount = 1;
}
#if DUMP_STATISTICS
if (++numLists > numListsHighWaterMark)
numListsHighWaterMark = numLists;
imp->sizeHighWaterMark = 0;
#endif
}
void List::derefValues()
{
ListImp *imp = static_cast<ListImp *>(_impBase);
int size = imp->size;
int inlineSize = MIN(size, inlineValuesSize);
for (int i = 0; i != inlineSize; ++i)
imp->values[i]->deref();
int overflowSize = size - inlineSize;
ValueImp **overflow = imp->overflow;
for (int i = 0; i != overflowSize; ++i)
overflow[i]->deref();
}
void List::refValues()
{
ListImp *imp = static_cast<ListImp *>(_impBase);
int size = imp->size;
int inlineSize = MIN(size, inlineValuesSize);
for (int i = 0; i != inlineSize; ++i)
imp->values[i]->ref();
int overflowSize = size - inlineSize;
ValueImp **overflow = imp->overflow;
for (int i = 0; i != overflowSize; ++i)
overflow[i]->ref();
}
void List::markValues()
{
ListImp *imp = static_cast<ListImp *>(_impBase);
int size = imp->size;
int inlineSize = MIN(size, inlineValuesSize);
for (int i = 0; i != inlineSize; ++i) {
if (!imp->values[i]->marked()) {
imp->values[i]->mark();
}
}
int overflowSize = size - inlineSize;
ValueImp **overflow = imp->overflow;
for (int i = 0; i != overflowSize; ++i) {
if (!overflow[i]->marked()) {
overflow[i]->mark();
}
}
}
void List::release()
{
ListImp *imp = static_cast<ListImp *>(_impBase);
#if DUMP_STATISTICS
--numLists;
++numListsDestroyed;
for (int i = 0; i < 17; i++)
if (imp->sizeHighWaterMark > i)
++numListsBiggerThan[i];
#endif
delete [] imp->overflow;
deallocateListImp(imp);
}
ValueImp *List::impAt(int i) const
{
ListImp *imp = static_cast<ListImp *>(_impBase);
if ((unsigned)i >= (unsigned)imp->size)
return UndefinedImp::staticUndefined;
if (i < inlineValuesSize)
return imp->values[i];
return imp->overflow[i - inlineValuesSize];
}
void List::clear()
{
if (_impBase->valueRefCount > 0) {
derefValues();
}
_impBase->size = 0;
}
void List::append(ValueImp *v)
{
ListImp *imp = static_cast<ListImp *>(_impBase);
int i = imp->size++;
#if DUMP_STATISTICS
if (imp->size > listSizeHighWaterMark)
listSizeHighWaterMark = imp->size;
#endif
if (imp->valueRefCount > 0) {
v->ref();
}
if (i < inlineValuesSize) {
imp->values[i] = v;
return;
}
if (i >= imp->capacity) {
int newCapacity = i * 2;
ValueImp **newOverflow = new ValueImp * [newCapacity - inlineValuesSize];
ValueImp **oldOverflow = imp->overflow;
int oldOverflowSize = i - inlineValuesSize;
for (int j = 0; j != oldOverflowSize; j++)
newOverflow[j] = oldOverflow[j];
delete [] oldOverflow;
imp->overflow = newOverflow;
imp->capacity = newCapacity;
}
imp->overflow[i - inlineValuesSize] = v;
}
List List::copy() const
{
List copy;
ListImp *imp = static_cast<ListImp *>(_impBase);
int size = imp->size;
int inlineSize = MIN(size, inlineValuesSize);
for (int i = 0; i != inlineSize; ++i)
copy.append(imp->values[i]);
ValueImp **overflow = imp->overflow;
int overflowSize = size - inlineSize;
for (int i = 0; i != overflowSize; ++i)
copy.append(overflow[i]);
return copy;
}
List List::copyTail() const
{
List copy;
ListImp *imp = static_cast<ListImp *>(_impBase);
int size = imp->size;
int inlineSize = MIN(size, inlineValuesSize);
for (int i = 1; i < inlineSize; ++i)
copy.append(imp->values[i]);
ValueImp **overflow = imp->overflow;
int overflowSize = size - inlineSize;
for (int i = 0; i < overflowSize; ++i)
copy.append(overflow[i]);
return copy;
}
const List &List::empty()
{
static List emptyList;
return emptyList;
}
} // namespace KJS
KJS::List::append
void append(const Value &val)
Append an object to the end of the list.
Definition: list.h:66
KJS::List::copyTail
List copyTail() const
Make a copy of the list, omitting the first element.
Definition: list.cpp:302
KJS::ValueImp
ValueImp is the base type for all primitives (Undefined, Null, Boolean, String, Number) and objects i...
Definition: value.h:79
KJS::List::size
int size() const
Definition: list.h:90
KJS::List::empty
static const List & empty()
Returns a pointer to a static instance of an empty list.
Definition: list.cpp:322
KJS::List::clear
void clear()
Remove all elements from the list.
Definition: list.cpp:238
KJS::List
Native list type.
Definition: list.h:48
KJS::List::copy
List copy() const
Make a copy of the list.
Definition: list.cpp:281

KDE Home | KDE Accessibility Home | Description of Access Keys