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- // This example shows how to sort structs using complex multiple part keys using
- // string_sort.
- //
- // Copyright Steven Ross 2009-2014.
- //
- // 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)
- // See http://www.boost.org/libs/sort for library home page.
- #include <boost/sort/spreadsort/string_sort.hpp>
- #include <boost/sort/spreadsort/float_sort.hpp>
- #include <time.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <algorithm>
- #include <vector>
- #include <iostream>
- #include <fstream>
- #include <string>
- using std::string;
- using namespace boost::sort::spreadsort;
- //[generalized_functors
- struct DATA_TYPE {
- time_t birth;
- float net_worth;
- string first_name;
- string last_name;
- };
- static const int birth_size = sizeof(time_t);
- static const int first_name_offset = birth_size + sizeof(float);
- static const boost::uint64_t base_mask = 0xff;
- struct lessthan {
- inline bool operator()(const DATA_TYPE &x, const DATA_TYPE &y) const {
- if (x.birth != y.birth) {
- return x.birth < y.birth;
- }
- if (x.net_worth != y.net_worth) {
- return x.net_worth < y.net_worth;
- }
- if (x.first_name != y.first_name) {
- return x.first_name < y.first_name;
- }
- return x.last_name < y.last_name;
- }
- };
- struct bracket {
- inline unsigned char operator()(const DATA_TYPE &x, size_t offset) const {
- // Sort date as a signed int, returning the appropriate byte.
- if (offset < birth_size) {
- const int bit_shift = 8 * (birth_size - offset - 1);
- unsigned char result = (x.birth & (base_mask << bit_shift)) >> bit_shift;
- // Handling the sign bit. Unnecessary if the data is always positive.
- if (offset == 0) {
- return result ^ 128;
- }
- return result;
- }
- // Sort a signed float. This requires reversing the order of negatives
- // because of the way floats are represented in bits.
- if (offset < first_name_offset) {
- const int bit_shift = 8 * (first_name_offset - offset - 1);
- unsigned key = float_mem_cast<float, unsigned>(x.net_worth);
- unsigned char result = (key & (base_mask << bit_shift)) >> bit_shift;
- // Handling the sign.
- if (x.net_worth < 0) {
- return 255 - result;
- }
- // Increasing positives so they are higher than negatives.
- if (offset == birth_size) {
- return 128 + result;
- }
- return result;
- }
- // Sort a string that is before the end. This approach supports embedded
- // nulls. If embedded nulls are not required, then just delete the "* 2"
- // and the inside of the following if just becomes:
- // return x.first_name[offset - first_name_offset];
- const unsigned first_name_end_offset =
- first_name_offset + x.first_name.size() * 2;
- if (offset < first_name_end_offset) {
- int char_offset = offset - first_name_offset;
- // This signals that the string continues.
- if (!(char_offset & 1)) {
- return 1;
- }
- return x.first_name[char_offset >> 1];
- }
- // This signals that the string has ended, so that shorter strings come
- // before longer ones.
- if (offset == first_name_end_offset) {
- return 0;
- }
- // The final string needs no special consideration.
- return x.last_name[offset - first_name_end_offset - 1];
- }
- };
- struct getsize {
- inline size_t operator()(const DATA_TYPE &x) const {
- return first_name_offset + x.first_name.size() * 2 + 1 +
- x.last_name.size();
- }
- };
- //] [/generalized_functors]
- //Pass in an argument to test std::sort
- int main(int argc, const char ** argv) {
- std::ifstream indata;
- std::ofstream outfile;
- bool stdSort = false;
- unsigned loopCount = 1;
- for (int u = 1; u < argc; ++u) {
- if (std::string(argv[u]) == "-std")
- stdSort = true;
- else
- loopCount = atoi(argv[u]);
- }
- double total = 0.0;
- //Run multiple loops, if requested
- std::vector<DATA_TYPE> array;
- for (unsigned u = 0; u < loopCount; ++u) {
- indata.open("input.txt", std::ios_base::in | std::ios_base::binary);
- if (indata.bad()) {
- printf("input.txt could not be opened\n");
- return 1;
- }
- // Read in the data.
- DATA_TYPE inval;
- while (!indata.eof() ) {
- indata >> inval.first_name;
- indata >> inval.last_name;
- indata.read(reinterpret_cast<char *>(&(inval.birth)), birth_size);
- indata.read(reinterpret_cast<char *>(&(inval.net_worth)), sizeof(float));
- // Handling nan.
- if (inval.net_worth != inval.net_worth) {
- inval.net_worth = 0;
- }
- if (indata.eof())
- break;
- array.push_back(inval);
- }
- indata.close();
- // Sort the data.
- clock_t start, end;
- double elapsed;
- start = clock();
- if (stdSort) {
- std::sort(array.begin(), array.end(), lessthan());
- } else {
- //[generalized_functors_call
- string_sort(array.begin(), array.end(), bracket(), getsize(), lessthan());
- //] [/generalized_functors_call]
- }
- end = clock();
- elapsed = static_cast<double>(end - start);
- if (stdSort) {
- outfile.open("standard_sort_out.txt", std::ios_base::out |
- std::ios_base::binary | std::ios_base::trunc);
- } else {
- outfile.open("boost_sort_out.txt", std::ios_base::out |
- std::ios_base::binary | std::ios_base::trunc);
- }
- if (outfile.good()) {
- for (unsigned u = 0; u < array.size(); ++u)
- outfile << array[u].birth << " " << array[u].net_worth << " "
- << array[u].first_name << " " << array[u].last_name << "\n";
- outfile.close();
- }
- total += elapsed;
- array.clear();
- }
- if (stdSort) {
- printf("std::sort elapsed time %f\n", total / CLOCKS_PER_SEC);
- } else {
- printf("spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC);
- }
- return 0;
- }
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