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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.
*/
#include "config.h"
#include "SmallStrings.h"
#include "JSGlobalObject.h"
#include "JSString.h"
#include <wtf/Noncopyable.h>
namespace JSC {
static const unsigned numCharactersToStore = 0x100;
class SmallStringsStorage : Noncopyable {
public:
SmallStringsStorage();
UString::Rep* rep(unsigned char character) { return &m_reps[character]; }
private:
UChar m_characters[numCharactersToStore];
UString::BaseString m_base;
UString::Rep m_reps[numCharactersToStore];
};
SmallStringsStorage::SmallStringsStorage()
: m_base(m_characters, numCharactersToStore)
{
m_base.rc = numCharactersToStore + 1;
// make sure UString doesn't try to reuse the buffer by pretending we have one more character in it
m_base.usedCapacity = numCharactersToStore + 1;
m_base.capacity = numCharactersToStore + 1;
m_base.checkConsistency();
for (unsigned i = 0; i < numCharactersToStore; ++i)
m_characters[i] = i;
memset(&m_reps, 0, sizeof(m_reps));
for (unsigned i = 0; i < numCharactersToStore; ++i) {
m_reps[i].offset = i;
m_reps[i].len = 1;
m_reps[i].rc = 1;
m_reps[i].setBaseString(&m_base);
m_reps[i].checkConsistency();
}
}
SmallStrings::SmallStrings()
: m_emptyString(0)
, m_storage(0)
{
COMPILE_ASSERT(numCharactersToStore == sizeof(m_singleCharacterStrings) / sizeof(m_singleCharacterStrings[0]), IsNumCharactersConstInSyncWithClassUsage);
for (unsigned i = 0; i < numCharactersToStore; ++i)
m_singleCharacterStrings[i] = 0;
}
SmallStrings::~SmallStrings()
{
}
void SmallStrings::mark()
{
if (m_emptyString && !m_emptyString->marked())
m_emptyString->mark();
for (unsigned i = 0; i < numCharactersToStore; ++i) {
if (m_singleCharacterStrings[i] && !m_singleCharacterStrings[i]->marked())
m_singleCharacterStrings[i]->mark();
}
}
unsigned SmallStrings::count() const
{
unsigned count = 0;
if (m_emptyString)
++count;
for (unsigned i = 0; i < numCharactersToStore; ++i) {
if (m_singleCharacterStrings[i])
++count;
}
return count;
}
void SmallStrings::createEmptyString(JSGlobalData* globalData)
{
ASSERT(!m_emptyString);
m_emptyString = new (globalData) JSString(globalData, "", JSString::HasOtherOwner);
}
void SmallStrings::createSingleCharacterString(JSGlobalData* globalData, unsigned char character)
{
if (!m_storage)
m_storage.set(new SmallStringsStorage);
ASSERT(!m_singleCharacterStrings[character]);
m_singleCharacterStrings[character] = new (globalData) JSString(globalData, m_storage->rep(character), JSString::HasOtherOwner);
}
UString::Rep* SmallStrings::singleCharacterStringRep(unsigned char character)
{
if (!m_storage)
m_storage.set(new SmallStringsStorage);
return m_storage->rep(character);
}
} // namespace JSC
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