26.adjacent.diff.cpp

Go to the documentation of this file.

 
#include <numeric>      // for adjacent_difference 
#include <cstddef>      // for size_t
 
#include <rw_alg_test.h>
#include <rw_value.h>   // for UserClass
#include <rw_driver.h>  // for rw_test()
 
 
// minus
template <class T>
struct minus: T
{
private:
    // unused member prevents bogus HP aCC warnings (see Onyx #23561)
    int unused;
};
 
 
template <class T>
const minus<T>& operator- (const minus<T>& lhs, const minus<T>& rhs) {
    _RWSTD_UNUSED(rhs);
    return lhs;
}
 
_RWSTD_NAMESPACE (std) { 
 
// disable explicit instantiation for compilers (like MSVC)
// that can't handle it
#ifndef _RWSTD_NO_EXPLICIT_INSTANTIATION
 
template 
OutputIter<minus<assign<base<cpy_ctor> > > >
adjacent_difference (InputIter<minus<assign<base<cpy_ctor> > > >,
                     InputIter<minus<assign<base<cpy_ctor> > > >,
                     OutputIter<minus<assign<base<cpy_ctor> > > >);
 
template 
OutputIter<assign<base<cpy_ctor> > > 
adjacent_difference (InputIter<assign<base<cpy_ctor> > >,
                     InputIter<assign<base<cpy_ctor> > >,
                     OutputIter<assign<base<cpy_ctor> > >,
                     binary_func<assign<base<cpy_ctor> > >);
 
#endif // _RWSTD_NO_EXPLICIT_INSTANTIATION
 
}   // namespace std
 
 
UserClass operator- (const UserClass &lhs, const UserClass &rhs)
{
    return UserClass (lhs)-= rhs;
}
 
 
template <class T>
struct conv_to_T
{
    static conv_to_T make (T val) {
        return conv_to_T (val);
    }
 
    // strictly convertible to a T value 
    operator T () const {
        return val_;
    }
 
private:
    // not (publicly) Default-Constructible
    conv_to_T (T val): val_ (val) { }
 
    void operator= (conv_to_T);   // not Assignable
    void operator!() const;       // not defined
 
    T val_;
};
 
 
struct Accumulator
{
    static std::size_t funcalls_;
 
    // dummy arguments provided to prevent the class from being
    // default constructible and implicit conversion from int
    Accumulator (int /* dummy */, int /* dummy */) {
        funcalls_ = 0;
    }
 
    // return a type convertible to UserClass
    conv_to_T<UserClass> operator() (const UserClass &x,
                                     const UserClass &y) /* non-const */ {
        ++funcalls_;
        UserClass res (x);
        res.data_.val_ -= y.data_.val_;
        return conv_to_T<UserClass>::make (res);
    }
 
private:
    void operator= (Accumulator&);   // not assignable
};
 
std::size_t Accumulator::funcalls_;
 
 
struct AdjacentDiffBase
{
    virtual ~AdjacentDiffBase() {}
 
    const char* iter_names [2];
 
    // pure virtual
    virtual UserClass*
    adjacent_difference (const UserClass   *xsrc, const UserClass  *xsrc_end,
                         UserClass         *xdst, const UserClass  *xdst_end,
                         const Accumulator *op) const = 0;
};
 
template <class InputIterator, class OutputIterator>
struct AdjacentDiff : AdjacentDiffBase
{
    AdjacentDiff () {
        iter_names [0] = type_name (InputIterator (0, 0, 0), (UserClass*)0);
        iter_names [1] = type_name (OutputIterator (0, 0, 0), (UserClass*)0);
    }
 
    virtual UserClass*
    adjacent_difference (const UserClass   *xsrc, const UserClass  *xsrc_end,
                         UserClass         *xdst, const UserClass  *xdst_end,
                         const Accumulator *op) const {
 
        const InputIterator  first (xsrc,     xsrc, xsrc_end);
        const InputIterator  last  (xsrc_end, xsrc, xsrc_end);
        const OutputIterator result (xdst,    xdst, xdst_end);
 
        const OutputIterator res = op ?
              std::adjacent_difference (first, last, result, *op)
            : std::adjacent_difference (first, last, result);
 
        // silence EDG eccp 3.7 and prior remark #550-D:
        //   variable was set but never used
        _RWSTD_UNUSED (res);
 
        return res.cur_;
    }
};
 
 
// exercises adjacent_difference (26.4.4)
void test_adjacent_difference (const std::size_t         N,
                               const AdjacentDiffBase   &alg,
                               bool                      binop,
                               bool                      same_seq)
{
    const char* const itname  =  alg.iter_names [0];
    const char* const outname = alg.iter_names [1];
    const char* const opname  = "Minus";
 
    rw_info (0, 0, 0, 
             "std::adjacent_difference(%s, %1$s, %s%{?}, %s%{;})%{?}, %s%{;}",
             itname, outname, binop, opname, same_seq, "first == result");
 
    UserClass::gen_ = gen_seq;
 
    UserClass* const src = new UserClass [N + 1];
    UserClass* dst = same_seq ? src : new UserClass [N + 1];
 
    static const int cwidth = sizeof (*src);
 
    for (std::size_t i = 0; i != N; ++i) {
 
        UserClass* const src_end = src + i;
        UserClass* const dst_end = dst + i;
 
        std::size_t last_n_op_minus_assign =
            UserClass::n_total_op_minus_assign_;
 
        const Accumulator   acc  (0, 0);
        const Accumulator* const pbinop = binop ? &acc : 0;
 
        std::size_t k = 0 < i ? i - 1 : 0;
        int* const tmp_val = new int [i + 1];
 
        for (; 0 < k; --k)
            tmp_val [k] = src [k].data_.val_ - src [k - 1].data_.val_;
 
        tmp_val [0] = src [0].data_.val_;
 
        const UserClass* const res =
            alg.adjacent_difference (src, src_end, dst, dst_end, pbinop);
 
        const std::size_t minus_ops = binop ?
              Accumulator::funcalls_
            : UserClass::n_total_op_minus_assign_ - last_n_op_minus_assign;
 
        // verify the returned iterator 26.4.4, p2
        bool success = res == dst_end;
        rw_assert (success, 0, __LINE__,
                   "adjacent_difference <%s, %s%{?}, %s%{;}>"
                   "({%{X=+*}}, ...) == result + %td, got result + %td",
                   itname, outname, binop, opname,
                   cwidth, int (i), src, dst_end - dst, res - dst);
 
        for (k = 0; k < i; k++) {
            success = dst [k].data_.val_ == tmp_val [k];
            if (!success)
                break;
        }
 
        // verify the result 26.4.4, p1
        if (0 < i) {
            // to avoid errors in --trace mode
            k = k < i ? k : i - 1;
 
            rw_assert (success, 0, __LINE__,
                       "adjacent_difference <%s, %s%{?}, %s%{;}>"
                       "({%{X=+*}}, ...) ==> {%{X=+*.*}}, expected %d",
                       itname, outname, binop, opname,
                       cwidth, int (i), src, int (i), int (k), dst, tmp_val [k]);
        }
 
        delete[] tmp_val;
 
        if (!success)
            break;
 
        // verify the complexity, 26.4.4, p3
        const std::size_t exp_minus_ops = 0 < i ? i - 1 : 0;
        success = minus_ops == exp_minus_ops;
        rw_assert (success, 0, __LINE__,
                   "adjacent_difference <%s, %s%{?}, %s%{;}>"
                   "({%{X=+*}}, ...) complexity: got %zu invocations "
                   "of %s, expected %zu",
                   itname, outname, binop, opname,
                   cwidth, int (i), src, minus_ops,
                   binop ? "BinaryMinus" : "operator-", exp_minus_ops);
 
        if (!success)
            break;
    }
 
    delete[] src;
 
    if (!same_seq)
        delete[] dst;
}
 
 
/* extern */ int rw_opt_nloops = 64;            // --nloops
/* extern */ int rw_opt_no_binary_op;           // --no-binary_op
/* extern */ int rw_opt_no_input_iter;          // --no-InputIterator
/* extern */ int rw_opt_no_output_iter;         // --no-OutputIterator
/* extern */ int rw_opt_no_fwd_iter;            // --no-ForwardIterator
/* extern */ int rw_opt_no_bidir_iter;          // --no-BidirectionalIterator
/* extern */ int rw_opt_no_rnd_iter;            // --no-RandomAccessIterator
 
 
template <class InputIterator, class OutputIterator>
void gen_adjacent_difference_test (const std::size_t N,
                                   const InputIterator&,
                                   const OutputIterator&,
                                   bool              binop)
{
    const AdjacentDiff<InputIterator, OutputIterator> alg;
 
    // test the algorithm than input and output arrays differ
    test_adjacent_difference (N, alg, binop, false);
 
    // test the algorithm than input and output arrays are the same
    test_adjacent_difference (N, alg, binop, true);
}
 
 
template <class InputIterator>
void gen_adjacent_difference_test (const std::size_t     N,
                                   const InputIterator  &it, 
                                   bool                  binop)
{
    if (0 == rw_opt_no_output_iter)
        gen_adjacent_difference_test (
            N, it, OutputIter<UserClass>(0, 0, 0), binop);
    if (0 == rw_opt_no_fwd_iter)
        gen_adjacent_difference_test (
            N, it, FwdIter<UserClass>(0, 0, 0), binop);
    if (0 == rw_opt_no_bidir_iter)
        gen_adjacent_difference_test (
            N, it, BidirIter<UserClass>(0, 0, 0), binop);
    if (0 == rw_opt_no_rnd_iter)
        gen_adjacent_difference_test (
            N, it, RandomAccessIter<UserClass>(0, 0, 0), binop);
}
 
// generates a specialization of the partial_sum test for each of the required
// iterator categopries
void gen_adjacent_difference_test (const std::size_t N,
                                   bool              binop)
{
    rw_info (0, 0, 0,
             "template <class %s, class %s%{?}, class %s%{;}> "
             "%2$s adjacent_difference (%1$s, %1$s, %2$s%{?}, %s%{;})", 
             "InputIterator", "OutputIterator", binop, "BinaryOperation", 
             binop, "BinaryOperation");
 
    if (rw_opt_no_output_iter)
        rw_note (0, 0, 0, "OutputIterator test disabled");
 
    if (rw_opt_no_input_iter)
        rw_note (0, 0, 0, "InputIterator test disabled");
    else
        gen_adjacent_difference_test (N, InputIter<UserClass>(0, 0, 0), binop);
 
    if (rw_opt_no_fwd_iter)
        rw_note (0, 0, 0, "ForwardIterator test disabled");
    else
        gen_adjacent_difference_test (N, ConstFwdIter<UserClass>(0, 0, 0),
                                      binop);
 
    if (rw_opt_no_bidir_iter)
        rw_note (0, 0, 0, "BidirectionalIterator test disabled");
    else
        gen_adjacent_difference_test (N, ConstBidirIter<UserClass>(0, 0, 0),
                                      binop);
 
    if (rw_opt_no_rnd_iter)
        rw_note (0, 0, 0, "RandomAccessIterator test disabled");
    else
        gen_adjacent_difference_test (N, 
            ConstRandomAccessIter<UserClass>(0, 0, 0), binop);
}
 
 
static int
run_test (int, char*[])
{
    const std::size_t N = std::size_t (rw_opt_nloops);
 
    gen_adjacent_difference_test (N, false);
 
    if (rw_opt_no_binary_op)
        rw_note (0, 0, 0, 
                 "adjacent_difference with binary operation test disabled");
    else
        gen_adjacent_difference_test (N, true);
 
    return 0;
}
 
 
int main (int argc, char *argv[])
{
    return rw_test (argc, argv, __FILE__,
                    "lib.adjacent.difference",
                    0 /* no comment */, run_test,
                    "|-nloops#0 "   // must be non-negative
                    "|-no-binary_op#"
                    "|-no-InputIterator# "
                    "|-no-OutputIterator# "
                    "|-no-ForwardIterator# "
                    "|-no-BidirectionalIterator# "
                    "|-no-RandomAccessIterator#",
                    &rw_opt_nloops,
                    &rw_opt_no_binary_op,
                    &rw_opt_no_input_iter,
                    &rw_opt_no_output_iter,
                    &rw_opt_no_fwd_iter,
                    &rw_opt_no_bidir_iter,
                    &rw_opt_no_rnd_iter);
}