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#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <iterator>
#include "test_helpers.hxx"
// For count_if workaround
#include <pqxx/config-internal-compiler.h>
using namespace PGSTD;
using namespace pqxx;
// Test program for libpqxx. Run a query and try various standard C++
// algorithms on it.
namespace
{
#ifndef PQXX_HAVE_COUNT_IF
template<typename IN, typename P> inline long count_if(IN first, IN last, P p)
{
long cnt;
for (cnt=0; first!=last; ++first) cnt += p(*first);
return cnt;
}
#endif
// Adds first element of each tuple it receives to a container
template<typename CONTAINER> struct Add
{
CONTAINER &Container;
string Key;
Add(string K, CONTAINER &C) : Container(C), Key(K) {}
void operator()(const pqxx::tuple &T)
{
Container.push_back(T[Key].c_str());
}
};
template<typename CONTAINER>
Add<CONTAINER> AdderFor(string K, CONTAINER &C)
{
return Add<CONTAINER>(K, C);
}
struct Cmp : binary_function<pqxx::tuple, pqxx::tuple, bool>
{
string Key;
explicit Cmp(string K) : Key(K) {}
bool operator()(const pqxx::tuple &L, const pqxx::tuple &R) const
{
return string(L[Key].c_str()) < string(R[Key].c_str());
}
};
struct CountGreaterSmaller : unary_function<pqxx::tuple, void>
{
string Key;
const result &R;
CountGreaterSmaller(string K, const result &X) : Key(K), R(X) {}
void operator()(const pqxx::tuple &T) const
{
// Count number of entries with key greater/smaller than first row's key
// using std::count_if<>()
const ptrdiff_t
Greater = count_if(R.begin(), R.end(), bind2nd(Cmp(Key),T)),
Smaller = count_if(R.begin(), R.end(), bind1st(Cmp(Key),T));
cout << "'" << T[Key] << "': "
<< Greater << " greater, "
<< Smaller << " smaller "
<< "(" << (Greater + Smaller) << " total)"
<< endl;
PQXX_CHECK(
Greater + Smaller < ptrdiff_t(R.size()),
"More non-equal rows than rows.");
}
};
void test_049(transaction_base &T)
{
string Table="pg_tables", Key="tablename";
result R( T.exec("SELECT * FROM " + Table + " ORDER BY " + Key) );
cout << "Read " << R.size() << " tuples." << endl;
PQXX_CHECK(!R.empty(), "No rows in " + Table + ".");
// Verify that for each key in R, the number of greater and smaller keys
// are sensible; use std::for_each<>() to iterate over rows in R
for_each(R.begin(), R.end(), CountGreaterSmaller(Key, R));
}
} // namespace
PQXX_REGISTER_TEST(test_049)
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