mng/test_mng.cpp

This is an example of use of completion handlers, stxxl::block_manager, and stxxl::typed_block

/***************************************************************************
 * mng/test_mng.cpp
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/


#include <iostream>
#include <stxxl/request>
#include <stxxl/mng>

#define BLOCK_SIZE (1024 * 512)

struct MyType
{
 int integer;
 //char chars[4];
 ~MyType() { }
};

struct my_handler
{
 void operator () (stxxl::request * req)
 {
 STXXL_MSG(req << " done, type=" << req->io_type());
 }
};

typedef stxxl::typed_block<BLOCK_SIZE, MyType> block_type;

int main()
{
 STXXL_MSG(sizeof(MyType) << " " << (BLOCK_SIZE % sizeof(MyType)));
 STXXL_MSG(sizeof(block_type) << " " << BLOCK_SIZE);
 const unsigned nblocks = 2;
 stxxl::BIDArray<BLOCK_SIZE> bids(nblocks);
 std::vector<int> disks(nblocks, 2);
 stxxl::request_ptr * reqs = new stxxl::request_ptr[nblocks];
 stxxl::block_manager * bm = stxxl::block_manager::get_instance();
 bm->new_blocks(stxxl::striping(), bids.begin(), bids.end());

 block_type * block = new block_type[2];
 STXXL_MSG(std::hex);
 STXXL_MSG("Allocated block address : " << long(block));
 STXXL_MSG("Allocated block address + 1: " << long(block + 1));
 STXXL_MSG(std::dec);
 unsigned i = 0;
 for (i = 0; i < block_type::size; ++i)
 {
 block->elem[i].integer = i;
 //memcpy (block->elem[i].chars, "STXXL", 4);
 }
 for (i = 0; i < nblocks; ++i)
 reqs[i] = block->write(bids[i], my_handler());


 std::cout << "Waiting " << std::endl;
 stxxl::wait_all(reqs, nblocks);

 for (i = 0; i < nblocks; ++i)
 {
 reqs[i] = block->read(bids[i], my_handler());
 reqs[i]->wait();
 for (int j = 0; j < block_type::size; ++j)
 {
 if (j != block->elem[j].integer)
 {
 STXXL_MSG("Error in block " << std::hex << i << " pos: " << j
 << " value read: " << block->elem[j].integer);
 }
 }
 }


 bm->delete_blocks(bids.begin(), bids.end());

 delete[] reqs;
 delete[] block;

#if 0
 // variable-size blocks, not supported currently

 BIDArray<0> vbids(nblocks);
 for (i = 0; i < nblocks; i++)
 vbids[i].size = 1024 + i;

 bm->new_blocks(striping(), vbids.begin(), vbids.end());

 for (i = 0; i < nblocks; i++)
 STXXL_MSG("Allocated block: offset=" << vbids[i].offset << ", size=" << vbids[i].size);

 bm->delete_blocks(vbids.begin(), vbids.end());
#endif
}