gecko-dev/xpcom/ds/nsArena.cpp

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2.0 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsIArena.h"
#include "nsCRT.h"
#define PL_ARENA_CONST_ALIGN_MASK 7
#include "plarena.h"
static NS_DEFINE_IID(kArenaIID, NS_IARENA_IID);
// Simple arena implementation layered on plarena
class ArenaImpl : public nsIArena {
public:
ArenaImpl(PRInt32 aBlockSize);
NS_DECL_ISUPPORTS
virtual void* Alloc(PRInt32 aSize);
protected:
~ArenaImpl();
PLArenaPool mPool;
PRInt32 mBlockSize;
};
ArenaImpl::ArenaImpl(PRInt32 aBlockSize)
{
NS_INIT_REFCNT();
if (aBlockSize < NS_MIN_ARENA_BLOCK_SIZE) {
aBlockSize = NS_DEFAULT_ARENA_BLOCK_SIZE;
}
PL_INIT_ARENA_POOL(&mPool, "nsIArena", aBlockSize);
mBlockSize = aBlockSize;
}
NS_IMPL_ISUPPORTS(ArenaImpl,kArenaIID)
ArenaImpl::~ArenaImpl()
{
PL_FinishArenaPool(&mPool);
}
void* ArenaImpl::Alloc(PRInt32 size)
{
// Adjust size so that it's a multiple of sizeof(double)
PRInt32 align = size & (sizeof(double) - 1);
if (0 != align) {
size += sizeof(double) - align;
}
void* p;
PL_ARENA_ALLOCATE(p, &mPool, size);
return p;
}
NS_BASE nsresult NS_NewHeapArena(nsIArena** aInstancePtrResult,
PRInt32 aArenaBlockSize)
{
ArenaImpl* it = new ArenaImpl(aArenaBlockSize);
if (nsnull == it) {
return NS_ERROR_OUT_OF_MEMORY;
}
return it->QueryInterface(kArenaIID, (void **) aInstancePtrResult);
}