102 lines
2.9 KiB
C++
102 lines
2.9 KiB
C++
//! \file
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//! \brief integer sort with a rightshift functor reverse sorting example.
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//
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// Copyright Steven Ross 2009-2014.
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/libs/sort for library home page.
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// Caution: this file contains Quickbook markup as well as code
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// and comments, don't change any of the special comment markups!
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#include <boost/sort/spreadsort/spreadsort.hpp>
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#include <time.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <algorithm>
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#include <vector>
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#include <string>
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#include <fstream>
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#include <iostream>
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#include <functional>
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using namespace boost::sort::spreadsort;
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#define DATA_TYPE int
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struct negrightshift {
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inline int operator()(const int &x, const unsigned offset) {
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return -(x >> offset);
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}
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};
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//Pass in an argument to test std::sort
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int main(int argc, const char ** argv) {
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size_t uCount,uSize=sizeof(DATA_TYPE);
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bool stdSort = false;
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unsigned loopCount = 1;
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for (int u = 1; u < argc; ++u) {
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if (std::string(argv[u]) == "-std")
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stdSort = true;
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else
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loopCount = atoi(argv[u]);
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}
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std::ifstream input("input.txt", std::ios_base::in | std::ios_base::binary);
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if (input.fail()) {
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printf("input.txt could not be opened\n");
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return 1;
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}
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double total = 0.0;
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std::vector<DATA_TYPE> array;
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input.seekg (0, std::ios_base::end);
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size_t length = input.tellg();
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uCount = length/uSize;
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//Run multiple loops, if requested
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for (unsigned u = 0; u < loopCount; ++u) {
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input.seekg (0, std::ios_base::beg);
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//Conversion to a vector
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array.resize(uCount);
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unsigned v = 0;
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while (input.good() && v < uCount)
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input.read(reinterpret_cast<char *>(&(array[v++])), uSize );
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if (v < uCount)
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array.resize(v);
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clock_t start, end;
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double elapsed;
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start = clock();
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if (stdSort)
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//[reverse_int_1
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std::sort(array.begin(), array.end(), std::greater<DATA_TYPE>());
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//] [/reverse_int_1]
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else
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//[reverse_int_2
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integer_sort(array.begin(), array.end(), negrightshift(), std::greater<DATA_TYPE>());
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//] [/reverse_int_2]
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end = clock();
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elapsed = static_cast<double>(end - start) ;
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std::ofstream ofile;
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if (stdSort)
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ofile.open("standard_sort_out.txt", std::ios_base::out |
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std::ios_base::binary | std::ios_base::trunc);
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else
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ofile.open("boost_sort_out.txt", std::ios_base::out |
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std::ios_base::binary | std::ios_base::trunc);
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if (ofile.good()) {
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for (unsigned v = 0; v < array.size(); ++v) {
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ofile.write(reinterpret_cast<char *>(&(array[v])), sizeof(array[v]));
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}
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ofile.close();
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}
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total += elapsed;
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array.clear();
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}
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if (stdSort)
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printf("std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
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else
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printf("spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
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return 0;
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}
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