Imported from /home/lorry/working-area/delta_boost-tarball/boost_1_58_0.tar.bz2.HEADboost_1_58_0master

1 files changed, 192 insertions, 0 deletions

diff --git a/libs/sort/example/generalizedstruct.cpp b/libs/sort/example/generalizedstruct.cpp
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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;

+}