1//! \brief Integer sort with a rightshift functor sorting example.
2//! \file
3//
4// Copyright Steven Ross 2009-2014.
5//
6// Distributed under the Boost Software License, Version 1.0.
7// (See accompanying file LICENSE_1_0.txt or copy at
8// http://www.boost.org/LICENSE_1_0.txt)
9
10// See http://www.boost.org/libs/sort for library home page.
11
12// Caution: this file contains Quickbook markup as well as code
13// and comments, don't change any of the special comment markups!
14
15#include <boost/sort/spreadsort/spreadsort.hpp>
16#include <time.h>
17#include <stdio.h>
18#include <stdlib.h>
19#include <algorithm>
20#include <vector>
21#include <string>
22#include <fstream>
23#include <iostream>
24using namespace boost::sort::spreadsort;
25
26#define DATA_TYPE int
27
28//[rightshift_int_functor
29struct rightshift {
30 inline int operator()(DATA_TYPE x, unsigned offset) { return x >> offset; }
31};
32//] [/rightshift_int_functor]
33
34//Pass in an argument to test std::sort
35int main(int argc, const char ** argv) {
36 size_t uCount,uSize=sizeof(DATA_TYPE);
37 bool stdSort = false;
38 unsigned loopCount = 1;
39 for (int u = 1; u < argc; ++u) {
40 if (std::string(argv[u]) == "-std")
41 stdSort = true;
42 else
43 loopCount = atoi(nptr: argv[u]);
44 }
45 std::ifstream input("input.txt", std::ios_base::in | std::ios_base::binary);
46 if (input.fail()) {
47 printf(format: "input.txt could not be opened\n");
48 return 1;
49 }
50 double total = 0.0;
51 std::vector<DATA_TYPE> array;
52 input.seekg (0, std::ios_base::end);
53 size_t length = input.tellg();
54 uCount = length/uSize;
55 //Run multiple loops, if requested
56 for (unsigned u = 0; u < loopCount; ++u) {
57 input.seekg (0, std::ios_base::beg);
58 //Conversion to a vector
59 array.resize(new_size: uCount);
60 unsigned v = 0;
61 while (input.good() && v < uCount)
62 input.read(s: reinterpret_cast<char *>(&(array[v++])), n: uSize );
63 if (v < uCount)
64 array.resize(new_size: v);
65 clock_t start, end;
66 double elapsed;
67 start = clock();
68 if (stdSort) {
69 std::sort(first: array.begin(), last: array.end());
70 } else {
71//[rightshift_1
72 integer_sort(first: array.begin(), last: array.end(), shift: rightshift());
73//] [/rightshift_1]
74 }
75 end = clock();
76 elapsed = static_cast<double>(end - start) ;
77 std::ofstream ofile;
78 if (stdSort)
79 ofile.open(s: "standard_sort_out.txt", mode: std::ios_base::out |
80 std::ios_base::binary | std::ios_base::trunc);
81 else
82 ofile.open(s: "boost_sort_out.txt", mode: std::ios_base::out |
83 std::ios_base::binary | std::ios_base::trunc);
84 if (ofile.good()) {
85 for (unsigned v = 0; v < array.size(); ++v) {
86 ofile.write(s: reinterpret_cast<char *>(&(array[v])), n: sizeof(array[v]) );
87 }
88 ofile.close();
89 }
90 total += elapsed;
91 array.clear();
92 }
93 if (stdSort)
94 printf(format: "std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
95 else
96 printf(format: "spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
97 return 0;
98}
99

source code of boost/libs/sort/example/rightshiftsample.cpp