зеркало из https://github.com/mozilla/gecko-dev.git
121 строка
2.9 KiB
C++
121 строка
2.9 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
/*
|
|
|
|
Implementation for nsFixedSizeAllocator
|
|
|
|
*/
|
|
|
|
#include "nsCRT.h"
|
|
#include "nsFixedSizeAllocator.h"
|
|
|
|
nsFixedSizeAllocator::Bucket *
|
|
nsFixedSizeAllocator::AddBucket(size_t aSize)
|
|
{
|
|
void* p;
|
|
PL_ARENA_ALLOCATE(p, &mPool, sizeof(Bucket));
|
|
if (! p)
|
|
return nullptr;
|
|
|
|
Bucket* bucket = static_cast<Bucket*>(p);
|
|
bucket->mSize = aSize;
|
|
bucket->mFirst = nullptr;
|
|
bucket->mNext = mBuckets;
|
|
|
|
mBuckets = bucket;
|
|
return bucket;
|
|
}
|
|
|
|
nsresult
|
|
nsFixedSizeAllocator::Init(const char* aName,
|
|
const size_t* aBucketSizes,
|
|
int32_t aNumBuckets,
|
|
int32_t aInitialSize,
|
|
int32_t aAlign)
|
|
{
|
|
NS_PRECONDITION(aNumBuckets > 0, "no buckets");
|
|
if (aNumBuckets <= 0)
|
|
return NS_ERROR_INVALID_ARG;
|
|
|
|
// Blow away the old pool if we're being re-initialized.
|
|
if (mBuckets)
|
|
PL_FinishArenaPool(&mPool);
|
|
|
|
int32_t bucketspace = aNumBuckets * sizeof(Bucket);
|
|
PL_InitArenaPool(&mPool, aName, bucketspace + aInitialSize, aAlign);
|
|
|
|
mBuckets = nullptr;
|
|
for (int32_t i = 0; i < aNumBuckets; ++i)
|
|
AddBucket(aBucketSizes[i]);
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
nsFixedSizeAllocator::Bucket *
|
|
nsFixedSizeAllocator::FindBucket(size_t aSize)
|
|
{
|
|
Bucket** link = &mBuckets;
|
|
Bucket* bucket;
|
|
|
|
while ((bucket = *link) != nullptr) {
|
|
if (aSize == bucket->mSize) {
|
|
// Promote to the head of the list, under the assumption
|
|
// that we'll allocate same-sized object contemporaneously.
|
|
*link = bucket->mNext;
|
|
bucket->mNext = mBuckets;
|
|
mBuckets = bucket;
|
|
return bucket;
|
|
}
|
|
|
|
link = &bucket->mNext;
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
void*
|
|
nsFixedSizeAllocator::Alloc(size_t aSize)
|
|
{
|
|
Bucket* bucket = FindBucket(aSize);
|
|
if (! bucket) {
|
|
// Oops, we don't carry that size. Let's fix that.
|
|
bucket = AddBucket(aSize);
|
|
if (! bucket)
|
|
return nullptr;
|
|
}
|
|
|
|
void* next;
|
|
if (bucket->mFirst) {
|
|
next = bucket->mFirst;
|
|
bucket->mFirst = bucket->mFirst->mNext;
|
|
}
|
|
else {
|
|
PL_ARENA_ALLOCATE(next, &mPool, aSize);
|
|
if (!next)
|
|
return nullptr;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
memset(next, 0xc8, aSize);
|
|
#endif
|
|
|
|
return next;
|
|
}
|
|
|
|
void
|
|
nsFixedSizeAllocator::Free(void* aPtr, size_t aSize)
|
|
{
|
|
FreeEntry* entry = reinterpret_cast<FreeEntry*>(aPtr);
|
|
Bucket* bucket = FindBucket(aSize);
|
|
|
|
#ifdef DEBUG
|
|
NS_ASSERTION(bucket && bucket->mSize == aSize, "ack! corruption! bucket->mSize != aSize!");
|
|
memset(aPtr, 0xd8, bucket->mSize);
|
|
#endif
|
|
|
|
entry->mNext = bucket->mFirst;
|
|
bucket->mFirst = entry;
|
|
}
|