llfio/example/sparse_array.cpp at develop · ned14/llfio · GitHub

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/* Examples of LLFIO use

File Created: Aug 2018

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 in the accompanying file

Licence.txt or 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.

Distributed under the Boost Software License, Version 1.0.

(See accompanying file Licence.txt or copy at

http://www.boost.org/LICENSE_1_0.txt)

#include "../include/llfio.hpp"

#include <future>

#include <iostream>

#include <vector>

// clang-format off

#ifdef _MSC_VER

#pragma warning(disable: 4706) // assignment within conditional

#endif

#if !defined(__SIZE_MAX__) || __SIZE_MAX__ > 999999999999UL

void sparse_array()

{

//! [sparse_array]

namespace llfio = LLFIO_V2_NAMESPACE;

// Make me a 1 trillion element sparsely allocated integer array!

llfio::mapped_file_handle mfh = llfio::mapped_temp_inode().value();

// On an extents based filing system, doesn't actually allocate any physical

// storage but does map approximately 4Tb of all bits zero data into memory

(void) mfh.truncate(1000000000000ULL * sizeof(int));

// Create a typed view of the one trillion integers

llfio::attached<int> one_trillion_int_array(mfh);

// Write and read as you see fit, if you exceed physical RAM it'll be paged out

one_trillion_int_array[0] = 5;

one_trillion_int_array[999999999999ULL] = 6;

//! [sparse_array]

}

#endif

int main()

{

return 0;

}

llfio/example/sparse_array.cpp at develop · ned14/llfio · GitHub

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