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// Copyright 2017 Google Inc. All Rights Reserved.
//
// 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 NB_MULTIPART_ALLOCATOR_H_
#define NB_MULTIPART_ALLOCATOR_H_
#include "starboard/configuration.h"
#include "starboard/types.h"
namespace nb {
// The class can fulfill allocation request by more than one blocks. It also
// provides a nested class to manage such allocations.
class MultipartAllocator {
public:
class Allocations {
public:
Allocations()
: number_of_buffers_(0), buffers_(NULL), buffer_sizes_(NULL) {}
Allocations(void* buffer, int buffer_size);
Allocations(int number_of_buffers, void** buffers, const int* buffer_sizes);
Allocations(const Allocations& that);
~Allocations();
Allocations& operator=(const Allocations& that);
int size() const;
void* const* buffers() { return buffers_; }
const void* const* buffers() const { return buffers_; }
const int* buffer_sizes() const { return buffer_sizes_; }
int number_of_buffers() const { return number_of_buffers_; }
void ShrinkTo(int size);
// Write |size| bytes from |src| to buffers start from |destination_offset|.
void Write(int destination_offset, const void* src, int size);
// Read data from the Allocations into |destination|. |destination| is
// guaranteed to have enough space to hold all data contained.
void Read(void* destination) const;
private:
void Assign(int number_of_buffers, void** buffers, const int* buffer_sizes);
void Destroy();
int number_of_buffers_;
void** buffers_;
int* buffer_sizes_;
// Store data in the class to avoid allocate memory when there is only one
// buffer. In this case |buffers_| and |buffer_sizes_| will point to
// |buffer_| and |buffer_size_| respectively.
void* buffer_;
int buffer_size_;
};
virtual ~MultipartAllocator() {}
// Allocate a memory block that contains at least |size| bytes and its
// address is aligned to |alignment|. It returns an empty Allocations object
// on failure.
virtual Allocations Allocate(size_t size,
size_t alignment,
intptr_t context) = 0;
// Free a memory block previously allocated by calling Allocate().
virtual void Free(Allocations allocations) = 0;
};
} // namespace nb
#endif // NB_MULTIPART_ALLOCATOR_H_