25.lower.bound.cpp

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#include <rw/_config.h>
 
#if defined (__IBMCPP__) && !defined (_RWSTD_NO_IMPLICIT_INCLUSION)
  // disable implicit inclusion to work around a limitation
  // of IBM VisualAge 5.0 (see PR #26959)
#  define _RWSTD_NO_IMPLICIT_INCLUSION 
#endif
 
#include <algorithm>
#include <cstring>
 
#include <rw_alg_test.h>
#include <rw_value.h>   // for UserClass
#include <rw_driver.h>
 
 
// distinct and not Less-Than-Comparable with class UserClass (except as
// defined below) to detect unwarranted assumptions made by the
// implementation of the algorithms
struct Y
{
    UserClass xval_;
 
    // not Default-Constructible
    Y (int /* dummy */, int /*dummy */): xval_ () { }
 
    // CopyConstructible
    Y (const Y &rhs): xval_ (rhs.xval_) { }
 
private:
 
    void operator=(Y&);   // not Assignable
};
 
inline conv_to_bool
operator< (const UserClass &lhs, const Y &rhs)
{
    return conv_to_bool::make (lhs < rhs.xval_);
}
 
 
// predicate used as the Compare argument to lower_bound()
struct LessThan
{
    static std::size_t funcalls_;
 
    LessThan (int /* dummy */, int /* dummy */) {
        funcalls_ = 0;
    }
 
    // return a type other than bool but one that is implicitly
    // convertible to bool to detect incorrect assumptions
    conv_to_bool operator() (const UserClass &lhs, const Y &rhs) {
        ++funcalls_;
        return conv_to_bool::make (lhs < rhs.xval_);
    }
 
private:
    void operator= (LessThan&);   // not assignable
};
 
std::size_t LessThan::funcalls_;
 
 
template <class ForwardIterator>
void test_lower_bound (int                    line,
                       const char            *src_str,
                       char                   val_char,
                       std::size_t            result_off,
                       std::size_t            ncomp,
                       const ForwardIterator*,
                       const char            *itname,
                       bool                   predicate)
{
    RW_ASSERT (0 != src_str);
 
    const std::size_t nsrc = std::strlen (src_str);
    UserClass* const xsrc = UserClass::from_char (src_str, nsrc);
 
    if (nsrc < result_off)
        result_off = nsrc;
 
    // construct the source range to pass to the algorithm
    const ForwardIterator first (xsrc,        xsrc,        xsrc + nsrc);
    const ForwardIterator last  (xsrc + nsrc, xsrc + nsrc, xsrc + nsrc);
 
    // construct the object to pass to the algorithm
    // the type of the object is distinct from the iterator's value_type
    // to detect unwarranted assumptions made by the implementation
    Y value (0, 0 /* dummy arguments */);
    value.xval_.data_.val_ = val_char;
 
    // construct the Compare function object to pass to the algorithm
    // when `predicate' is true
    const LessThan comp (0, 0 /* dummy arguments */);
 
    // reset the counter of invocations of UserClass::operator<()
    UserClass::n_total_op_lt_ = 0;
 
    // invoke the appropriate form of the algorithm, storing
    // the resturned value
    const ForwardIterator result = predicate
        ? std::lower_bound (first, last, value, comp)
        : std::lower_bound (first, last, value);
 
    // silence bogus EDG eccp 3.6 remark #550-D:
    // variable was set but never used
    _RWSTD_UNUSED (result);
 
    // verify correctness
    const std::size_t off = std::size_t (result.cur_ - xsrc);
 
    rw_assert (off == result_off, 0, line,
               "lower_bound(%s = \"%s\", ...%{?}%#c%{;}) ==> "
               "first + %zu, got %zu",
               itname, src_str, !predicate, val_char,
               off, result_off);
 
    // verify complexity
    const std::size_t funcalls = predicate
        ? LessThan::funcalls_ : UserClass::n_total_op_lt_;
 
    rw_assert (funcalls <= ncomp, 0, line,
               "lower_bound(%s = \"%s\", ...%{?}%#c%{;}) complexity: "
               "invoked predicate at most %zu times, got %zu",
               itname, src_str, !predicate, val_char,
               ncomp, funcalls);
 
    delete[] xsrc;
}
 
 
template <class ForwardIterator>
void test_lower_bound (const ForwardIterator*,
                       const char           *itname,
                       bool                  predicate)
{
#define TEST(str, val, off, comp) \
    test_lower_bound (__LINE__, str, val, std::size_t (off), \
                      std::size_t (comp), (ForwardIterator*)0, \
                      itname, predicate)
 
    rw_info (0, 0, 0,
             "std::lower_bound (%s, %1$s, const UserClass&%{?}, %s%{;})",
             itname, predicate, "LessThan");
 
    //    +--------------- source sequence
    //    |     +--------- value argument
    //    |     |   +----- offset of the resturned iterator, -1 for end
    //    |     |   |  +-- complexity: at most (log(last - first) + 1)
    //    |     |   |  |   comparisons (or applications of the predicate)
    //    |     |   |  |
    //    V     V   V  V
    TEST ("",  'a', 0, 0);
    TEST ("a", 'a', 0, 1);
    TEST ("a", 'b', 1, 1);
    TEST ("b", 'a', 0, 1);
 
    TEST ("aa", 'a', 0, 2);
    TEST ("ab", 'a', 0, 2);
    TEST ("ab", 'b', 1, 2);
    TEST ("bb", 'a', 0, 2);
 
    TEST ("ace", 'a', 0, 3);
    TEST ("ace", 'b', 1, 3);
    TEST ("ace", 'c', 1, 3);
    TEST ("ace", 'd', 2, 3);
    TEST ("ace", 'e', 2, 3);
    TEST ("ace", 'f', 3, 3);
 
    TEST ("aceg", 'a', 0, 3);
    TEST ("aceg", 'b', 1, 3);
    TEST ("aceg", 'c', 1, 3);
    TEST ("aceg", 'd', 2, 3);
    TEST ("aceg", 'e', 2, 3);
    TEST ("aceg", 'f', 3, 3);
    TEST ("aceg", 'g', 3, 3);
    TEST ("aceg", 'h', 4, 3);
}
 
 
static int rw_opt_no_fwd_iter;
static int rw_opt_no_bidir_iter;
static int rw_opt_no_rnd_iter;
static int rw_opt_no_predicate;
 
 
static void
test_lower_bound (bool predicate)
{
    rw_info (0, 0, 0, "template <class %s, class %s%{?}, class %s%{;}> "
             "std::lower_bound (%1$s, %1$s, const UserClass&%{?}, %4$s%{;})",
             "ForwardIterator", "UserClass", predicate, "Compare", predicate);
 
    if (rw_opt_no_fwd_iter) {
        rw_note (0, 0, 0, "ForwardIterator test disabled");
    }
    else {
        test_lower_bound ((FwdIter<UserClass>*)0, "ForwardIterator", predicate);
    }
 
    if (rw_opt_no_bidir_iter) {
        rw_note (0, 0, 0, "BidirectionalIterator test disabled");
    }
    else {
        test_lower_bound ((BidirIter<UserClass>*)0, "BidirectionalIterator",
                          predicate);
    }
 
    if (rw_opt_no_fwd_iter) {
        rw_note (0, 0, 0, "RandomAccessIterator test disabled");
    }
    else {
        test_lower_bound ((RandomAccessIter<UserClass>*)0,
                          "RandomAccessIterator", predicate);
    }
}
 
 
static int
run_test (int, char*[])
{
    test_lower_bound (false);
 
    if (rw_opt_no_predicate) {
        rw_note (0, __FILE__, __LINE__,
                 "test of the Predicate form of std::lower_bound disabled");
    }
    else {
        test_lower_bound (true);
    }
 
    return 0;
}
 
 
int main (int argc, char *argv[])
{
    return rw_test (argc, argv, __FILE__,
                    "lib.lower.bound",
                    0 /* no comment */,
                    run_test,
                    "|-no-Predicate# "
                    "|-no-ForwardIterator# "
                    "|-no-BidirectionalIterator# "
                    "|-no-RandomAccessIterator#",
                    &rw_opt_no_predicate,
                    &rw_opt_no_fwd_iter,
                    &rw_opt_no_bidir_iter,
                    &rw_opt_no_rnd_iter);
}