Add performance tests from Karma.

tests/int_generator.cpp

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+//  Copyright (c) 2001-2010 Hartmut Kaiser
+// 
+//  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)
+
+#include <climits>
+#include <cstdlib>
+
+#include <iostream> 
+#include <sstream>
+#include <boost/format.hpp>
+
+#include "../high_resolution_timer.hpp"
+
+//  This value specifies, how to unroll the integer string generation loop in 
+//  Karma.
+//      Set this to some integer in between 0 (no unrolling) and max expected 
+//      integer string len (complete unrolling). If not specified, this value
+//      defaults to 6.
+#define BOOST_KARMA_NUMERICS_LOOP_UNROLL 6
+
+#include <boost/spirit/include/karma.hpp>
+
+using namespace std;
+using namespace boost::spirit;
+
+#define MAX_ITERATION 10000000
+
+///////////////////////////////////////////////////////////////////////////////
+struct random_fill
+{
+    int operator()() const
+    {
+        int scale = std::rand() / 100 + 1;
+        return (std::rand() * std::rand()) / scale;
+    }
+};
+
+///////////////////////////////////////////////////////////////////////////////
+int main()
+{
+    namespace karma = boost::spirit::karma;
+
+    cout << "Converting " << MAX_ITERATION 
+         << " randomly generated int values to strings." << flush << endl;
+
+    std::srand(0);
+    std::vector<int> v (MAX_ITERATION);
+    std::generate(v.begin(), v.end(), random_fill()); // randomly fill the vector
+
+    // test the C libraries ltoa function (the most low level function for
+    // string conversion available)
+    {
+        //[karma_int_performance_ltoa
+        char buffer[65]; // we don't expect more than 64 bytes to be generated here
+        //<-
+        std::string str;
+        util::high_resolution_timer t;
+        //->
+        for (int i = 0; i < MAX_ITERATION; ++i)
+        {
+            ltoa(v[i], buffer, 10);
+            //<-
+            str = buffer;      // compensate for string ops in other benchmarks
+            //->
+        }
+        //]
+
+        cout << "ltoa:\t\t" << t.elapsed() << " [s]" << flush << endl;
+    }
+
+    // test the iostreams library
+    {
+        //[karma_int_performance_iostreams
+        std::stringstream str;
+        //<-
+        util::high_resolution_timer t;
+        //->
+        for (int i = 0; i < MAX_ITERATION; ++i)
+        {
+            str.str("");
+            str << v[i];
+        }
+        //]
+
+        cout << "iostreams:\t" << t.elapsed() << " [s]" << flush << endl;
+    }
+
+    // test the Boost.Format library
+    {
+        //[karma_int_performance_format
+        std::string str;
+        boost::format int_format("%d");
+        //<-
+        util::high_resolution_timer t;
+        //->
+        for (int i = 0; i < MAX_ITERATION; ++i)
+        {
+            str = boost::str(int_format % v[i]);
+        }
+        //]
+
+        cout << "Boost.Format:\t" << t.elapsed() << " [s]" << flush << endl;
+    }
+
+    // test the Karma int_ generation routines 
+    {
+        std::string str;
+        util::high_resolution_timer t;
+
+        //[karma_int_performance_plain
+        char buffer[65]; // we don't expect more than 64 bytes to be generated here
+        for (int i = 0; i < MAX_ITERATION; ++i)
+        {
+            char *ptr = buffer;
+            karma::generate(ptr, int_, v[i]);
+            *ptr = '\0';
+            //<-
+            str = buffer;      // compensate for string ops in other benchmarks
+            //->
+        }
+        //]
+
+        cout << "int_:\t\t" << t.elapsed() << " [s]" << flush << endl;
+    }
+
+    return 0;
+}
+