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1 | // This example shows how to sort structs using complex multiple part keys using |
2 | // string_sort. | |
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 | #include <boost/sort/spreadsort/string_sort.hpp> | |
13 | #include <boost/sort/spreadsort/float_sort.hpp> | |
14 | #include <time.h> | |
15 | #include <stdio.h> | |
16 | #include <stdlib.h> | |
17 | #include <algorithm> | |
18 | #include <vector> | |
19 | #include <iostream> | |
20 | #include <fstream> | |
21 | #include <string> | |
22 | using std::string; | |
23 | using namespace boost::sort::spreadsort; | |
24 | ||
25 | //[generalized_functors | |
26 | struct DATA_TYPE { | |
27 | time_t birth; | |
28 | float net_worth; | |
29 | string first_name; | |
30 | string last_name; | |
31 | }; | |
32 | ||
33 | static const int birth_size = sizeof(time_t); | |
34 | static const int first_name_offset = birth_size + sizeof(float); | |
35 | static const boost::uint64_t base_mask = 0xff; | |
36 | ||
37 | struct lessthan { | |
38 | inline bool operator()(const DATA_TYPE &x, const DATA_TYPE &y) const { | |
39 | if (x.birth != y.birth) { | |
40 | return x.birth < y.birth; | |
41 | } | |
42 | if (x.net_worth != y.net_worth) { | |
43 | return x.net_worth < y.net_worth; | |
44 | } | |
45 | if (x.first_name != y.first_name) { | |
46 | return x.first_name < y.first_name; | |
47 | } | |
48 | return x.last_name < y.last_name; | |
49 | } | |
50 | }; | |
51 | ||
52 | struct bracket { | |
53 | inline unsigned char operator()(const DATA_TYPE &x, size_t offset) const { | |
54 | // Sort date as a signed int, returning the appropriate byte. | |
55 | if (offset < birth_size) { | |
56 | const int bit_shift = 8 * (birth_size - offset - 1); | |
57 | unsigned char result = (x.birth & (base_mask << bit_shift)) >> bit_shift; | |
58 | // Handling the sign bit. Unnecessary if the data is always positive. | |
59 | if (offset == 0) { | |
60 | return result ^ 128; | |
61 | } | |
62 | ||
63 | return result; | |
64 | } | |
65 | ||
66 | // Sort a signed float. This requires reversing the order of negatives | |
67 | // because of the way floats are represented in bits. | |
68 | if (offset < first_name_offset) { | |
69 | const int bit_shift = 8 * (first_name_offset - offset - 1); | |
70 | unsigned key = float_mem_cast<float, unsigned>(x.net_worth); | |
71 | unsigned char result = (key & (base_mask << bit_shift)) >> bit_shift; | |
72 | // Handling the sign. | |
73 | if (x.net_worth < 0) { | |
74 | return 255 - result; | |
75 | } | |
76 | // Increasing positives so they are higher than negatives. | |
77 | if (offset == birth_size) { | |
78 | return 128 + result; | |
79 | } | |
80 | ||
81 | return result; | |
82 | } | |
83 | ||
84 | // Sort a string that is before the end. This approach supports embedded | |
85 | // nulls. If embedded nulls are not required, then just delete the "* 2" | |
86 | // and the inside of the following if just becomes: | |
87 | // return x.first_name[offset - first_name_offset]; | |
88 | const unsigned first_name_end_offset = | |
89 | first_name_offset + x.first_name.size() * 2; | |
90 | if (offset < first_name_end_offset) { | |
91 | int char_offset = offset - first_name_offset; | |
92 | // This signals that the string continues. | |
93 | if (!(char_offset & 1)) { | |
94 | return 1; | |
95 | } | |
96 | return x.first_name[char_offset >> 1]; | |
97 | } | |
98 | ||
99 | // This signals that the string has ended, so that shorter strings come | |
100 | // before longer ones. | |
101 | if (offset == first_name_end_offset) { | |
102 | return 0; | |
103 | } | |
104 | ||
105 | // The final string needs no special consideration. | |
106 | return x.last_name[offset - first_name_end_offset - 1]; | |
107 | } | |
108 | }; | |
109 | ||
110 | struct getsize { | |
111 | inline size_t operator()(const DATA_TYPE &x) const { | |
112 | return first_name_offset + x.first_name.size() * 2 + 1 + | |
113 | x.last_name.size(); | |
114 | } | |
115 | }; | |
116 | //] [/generalized_functors] | |
117 | ||
118 | //Pass in an argument to test std::sort | |
119 | int main(int argc, const char ** argv) { | |
120 | std::ifstream indata; | |
121 | std::ofstream outfile; | |
122 | bool stdSort = false; | |
123 | unsigned loopCount = 1; | |
124 | for (int u = 1; u < argc; ++u) { | |
125 | if (std::string(argv[u]) == "-std") | |
126 | stdSort = true; | |
127 | else | |
128 | loopCount = atoi(argv[u]); | |
129 | } | |
130 | double total = 0.0; | |
131 | //Run multiple loops, if requested | |
132 | std::vector<DATA_TYPE> array; | |
133 | for (unsigned u = 0; u < loopCount; ++u) { | |
134 | indata.open("input.txt", std::ios_base::in | std::ios_base::binary); | |
135 | if (indata.bad()) { | |
136 | printf("input.txt could not be opened\n"); | |
137 | return 1; | |
138 | } | |
139 | ||
140 | // Read in the data. | |
141 | DATA_TYPE inval; | |
142 | while (!indata.eof() ) { | |
143 | indata >> inval.first_name; | |
144 | indata >> inval.last_name; | |
145 | indata.read(reinterpret_cast<char *>(&(inval.birth)), birth_size); | |
146 | indata.read(reinterpret_cast<char *>(&(inval.net_worth)), sizeof(float)); | |
147 | // Handling nan. | |
148 | if (inval.net_worth != inval.net_worth) { | |
149 | inval.net_worth = 0; | |
150 | } | |
151 | if (indata.eof()) | |
152 | break; | |
153 | array.push_back(inval); | |
154 | } | |
155 | indata.close(); | |
156 | ||
157 | // Sort the data. | |
158 | clock_t start, end; | |
159 | double elapsed; | |
160 | start = clock(); | |
161 | if (stdSort) { | |
162 | std::sort(array.begin(), array.end(), lessthan()); | |
163 | } else { | |
164 | //[generalized_functors_call | |
165 | string_sort(array.begin(), array.end(), bracket(), getsize(), lessthan()); | |
166 | //] [/generalized_functors_call] | |
167 | } | |
168 | end = clock(); | |
169 | elapsed = static_cast<double>(end - start); | |
170 | if (stdSort) { | |
171 | outfile.open("standard_sort_out.txt", std::ios_base::out | | |
172 | std::ios_base::binary | std::ios_base::trunc); | |
173 | } else { | |
174 | outfile.open("boost_sort_out.txt", std::ios_base::out | | |
175 | std::ios_base::binary | std::ios_base::trunc); | |
176 | } | |
177 | if (outfile.good()) { | |
178 | for (unsigned u = 0; u < array.size(); ++u) | |
179 | outfile << array[u].birth << " " << array[u].net_worth << " " | |
180 | << array[u].first_name << " " << array[u].last_name << "\n"; | |
181 | outfile.close(); | |
182 | } | |
183 | total += elapsed; | |
184 | array.clear(); | |
185 | } | |
186 | if (stdSort) { | |
187 | printf("std::sort elapsed time %f\n", total / CLOCKS_PER_SEC); | |
188 | } else { | |
189 | printf("spreadsort elapsed time %f\n", total / CLOCKS_PER_SEC); | |
190 | } | |
191 | return 0; | |
192 | } |