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// Copyright 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#include "base/AlignedBuf.h"
#include <vector>
#include <unordered_set>
#include <inttypes.h>
namespace android {
namespace base {
// Class to make it easier to set up memory regions where it is fast
// to allocate buffers AND we don't care about freeing individual pieces,
// BUT it's necessary to preserve previous pointer values in between the first
// alloc() after a freeAll(), and the freeAll() itself, allowing some sloppy use of
// malloc in the first pass while we find out how much data was needed.
class BumpPool {
public:
BumpPool(size_t startingBytes = 4096) : mStorage(startingBytes / sizeof(uint64_t)) { }
// All memory allocated by this pool
// is automatically deleted when the pool
// is deconstructed.
~BumpPool() { }
void* alloc(size_t wantedSize) {
size_t wantedSizeRoundedUp =
sizeof(uint64_t) * ((wantedSize + sizeof(uint64_t) - 1) / (sizeof(uint64_t)));
mTotalWantedThisGeneration += wantedSizeRoundedUp;
if (mAllocPos + wantedSizeRoundedUp > mStorage.size()) {
mNeedRealloc = true;
void* fallbackPtr = malloc(wantedSizeRoundedUp);
mFallbackPtrs.insert(fallbackPtr);
return fallbackPtr;
}
size_t avail = mStorage.size() - mAllocPos;
void* allocPtr = (void*)(mStorage.data() + mAllocPos);
mAllocPos += wantedSizeRoundedUp;
return allocPtr;
}
void freeAll() {
mAllocPos = 0;
if (mNeedRealloc) {
mStorage.resize((mTotalWantedThisGeneration * 2) / sizeof(uint64_t));
mNeedRealloc = false;
for (auto ptr : mFallbackPtrs) {
free(ptr);
}
mFallbackPtrs.clear();
}
mTotalWantedThisGeneration = 0;
}
// Convenience function to allocate an array
// of objects of type T.
template <class T>
T* allocArray(size_t count) {
size_t bytes = sizeof(T) * count;
void* res = alloc(bytes);
return (T*) res;
}
char* strDup(const char* toCopy) {
size_t bytes = strlen(toCopy) + 1;
void* res = alloc(bytes);
memset(res, 0x0, bytes);
memcpy(res, toCopy, bytes);
return (char*)res;
}
char** strDupArray(const char* const* arrayToCopy, size_t count) {
char** res = allocArray<char*>(count);
for (size_t i = 0; i < count; i++) {
res[i] = strDup(arrayToCopy[i]);
}
return res;
}
void* dupArray(const void* buf, size_t bytes) {
void* res = alloc(bytes);
memcpy(res, buf, bytes);
return res;
}
private:
AlignedBuf<uint64_t, 8> mStorage;
std::unordered_set<void*> mFallbackPtrs;
size_t mAllocPos = 0;
size_t mTotalWantedThisGeneration = 0;
bool mNeedRealloc = false;
};
} // namespace base
} // namespace android
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