chromium/third_party/perfetto/src/trace_processor/util/bump_allocator.h

/*
 * Copyright (C) 2023 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.
 */

#ifndef SRC_TRACE_PROCESSOR_UTIL_BUMP_ALLOCATOR_H_
#define SRC_TRACE_PROCESSOR_UTIL_BUMP_ALLOCATOR_H_

#include <cmath>
#include <cstdint>
#include <cstring>
#include <limits>
#include <memory>
#include <optional>
#include <tuple>

#include "perfetto/ext/base/circular_queue.h"
#include "perfetto/ext/base/utils.h"

namespace perfetto {
namespace trace_processor {

// A simple memory allocator which "bumps" a pointer to service allocations.
// See [1] for more details for an overview of bump allocators.
//
// This implementation works by obtaining a large chunk of memory from the
// system allocator (i.e. from malloc). Every allocation uses that chunk as long
// as there is free space inside. Once an allocation is requested which does not
// fit in that chunk, a new chunk is requested from the system.
//
// IMPORTANT: all allocations returned from this allocator are 8-aligned and
// all allocation sizes must be a multiple of 8.
//
// IMPORTANT: this allocator can allocate a total of 4GB of memory (2^32). Once
// this is exhausted, any further allocation will cause a CHECK.
//
// IMPORTANT: all allocations *must* be explicitly freed before destroying this
// object. The destructor will CHECK if it detects any allocation which is
// unfreed.
//
// [1] https://rust-hosted-langs.github.io/book/chapter-simple-bump.html
class BumpAllocator { … };

}  // namespace trace_processor
}  // namespace perfetto

#endif  // SRC_TRACE_PROCESSOR_UTIL_BUMP_ALLOCATOR_H_