lib/magma/src/magma_util/retry_allocator.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef RETRY_ALLOCATOR_H
#define RETRY_ALLOCATOR_H

#include <map>

#include <lib/fit/function.h>

#include "macros.h"

namespace magma {

// This is an allocator that calls a user-specified allocation function on the proposed address
// range, and if that fails it tries new address ranges until it succeeds or it runs out of address
// space.
class RetryAllocator final {
public:
    using AllocationFunction = fit::function<bool(uint64_t)>;

    static std::unique_ptr<RetryAllocator> Create(uint64_t base, uint64_t size);

    bool Alloc(size_t size, uint8_t align_pow2, AllocationFunction map_function,
               uint64_t* addr_out);
    bool Free(uint64_t addr, uint64_t size);

    uint64_t base() const { return base_; }
    uint64_t size() const { return size_; }

private:
    RetryAllocator(uint64_t base, size_t size);

    // Retrys from the address to the length of the region.
    std::map<uint64_t, uint64_t> free_regions_;

    uint64_t base_;
    uint64_t size_;

    DISALLOW_COPY_AND_ASSIGN(RetryAllocator);
};

} // namespace magma

#endif // RETRY_ALLOCATOR_H