io/test_io.cpp

This is an example of use of <stxxl> files, requests, and completion tracking mechanisms, i.e. stxxl::file , stxxl::request

/***************************************************************************
 * io/test_io.cpp
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 * Copyright (C) 2008, 2009 Andreas Beckmann <[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 <limits>
#include <stxxl/io>
#include <stxxl/aligned_alloc>


using stxxl::file;


struct my_handler
{
 void operator () (stxxl::request * ptr)
 {
 STXXL_MSG("Request completed: " << ptr);
 }
};

int main(int argc, char ** argv)
{
 if (argc < 2)
 {
 std::cout << "Usage: " << argv[0] << " tempdir" << std::endl;
 return -1;
 }

 std::string tempfilename[2];
 tempfilename[0] = std::string(argv[1]) + "/test_io_1.dat";
 tempfilename[1] = std::string(argv[1]) + "/test_io_2.dat";

 std::cout << sizeof(void *) << std::endl;
 const int size = 1024 * 384;
 char * buffer = (char *)stxxl::aligned_alloc<4096>(size);
 memset(buffer, 0, size);

#ifndef BOOST_MSVC
 stxxl::mmap_file file1(tempfilename[0], file::CREAT | file::RDWR /* | file::DIRECT */, 0);
 file1.set_size(size * 1024);
#endif

 stxxl::syscall_file file2(tempfilename[1], file::CREAT | file::RDWR /* | file::DIRECT */, 1);

 stxxl::request_ptr req[16];
 unsigned i;
 for (i = 0; i < 16; i++)
 req[i] = file2.awrite(buffer, i * size, size, my_handler());

 wait_all(req, 16);

 // check behaviour of having requests to the same location at the same time
 for (i = 2; i < 16; i++)
 req[i] = file2.awrite(buffer, 0, size, my_handler());
 req[0] = file2.aread(buffer, 0, size, my_handler());
 req[1] = file2.awrite(buffer, 0, size, my_handler());

 wait_all(req, 16);

 stxxl::aligned_dealloc<4096>(buffer);

 std::cout << *(stxxl::stats::get_instance());

 stxxl::uint64 sz;
 for (sz = 123, i = 0; i < 20; ++i, sz *= 10)
 STXXL_MSG(">>>" << stxxl::add_SI_multiplier(sz) << "<<<");
 for (sz = 123, i = 0; i < 20; ++i, sz *= 10)
 STXXL_MSG(">>>" << stxxl::add_SI_multiplier(sz, "B") << "<<<");
 STXXL_MSG(">>>" << stxxl::add_SI_multiplier((std::numeric_limits<stxxl::uint64>::max)(), "B") << "<<<");
 for (sz = 123, i = 0; i < 20; ++i, sz *= 10)
 STXXL_MSG(">>>" << stxxl::add_IEC_binary_multiplier(sz) << "<<<");
 for (sz = 123, i = 0; i < 20; ++i, sz *= 10)
 STXXL_MSG(">>>" << stxxl::add_IEC_binary_multiplier(sz, "B") << "<<<");
 STXXL_MSG(">>>" << stxxl::add_IEC_binary_multiplier((std::numeric_limits<stxxl::uint64>::max)(), "B") << "<<<");

 unlink(tempfilename[0].c_str());
 unlink(tempfilename[1].c_str());

 return 0;
}