forked from boostorg/integer
77 lines
2.9 KiB
C++
77 lines
2.9 KiB
C++
// boost integer_mask.hpp test program -------------------------------------//
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// (C) Copyright Daryle Walker 2001.
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org for most recent version including documentation.
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// Revision History
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// 27 Jul 2008 Changed tests to use the unit-test system; added
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// extended-integer support. (Daryle Walker)
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// 23 Sep 2001 Initial version (Daryle Walker)
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#define BOOST_TEST_MODULE "Integer mask tests"
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#include <boost/test/unit_test.hpp> // unit testing framework
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#include <boost/cstdint.hpp> // for boost::uintmax_t
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#include <boost/integer/integer_mask.hpp> // for boost::high_bit_mask_t, etc.
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#include <boost/limits.hpp> // for std::numeric_limits
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#include <boost/mpl/assert.hpp> // for BOOST_MPL_ASSERT_RELATION
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#include <boost/mpl/range_c.hpp> // for boost::mpl::range_c
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#include <cstddef> // for std::size_t
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// Custom types/templates, helper functions, and objects
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namespace
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{
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// A big one
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boost::uintmax_t const one = 1u;
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// List the ranges of template parameters tests (ranges are half-open)
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int const max_offset = std::numeric_limits<boost::uintmax_t>::digits;
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typedef boost::mpl::range_c<std::size_t, 0, max_offset> high_bit_offsets;
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typedef boost::mpl::range_c<std::size_t, 1, max_offset + 1> low_bit_lengths;
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} // unnamed namespace
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// Check the various integer-valued bit-masks
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BOOST_AUTO_TEST_SUITE( integer_mask_tests )
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// Check the bit-masks of one offset bit
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BOOST_AUTO_TEST_CASE_TEMPLATE( high_bit_mask_test, T, high_bit_offsets )
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{
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BOOST_MPL_ASSERT_RELATION( boost::high_bit_mask_t<T::value>::high_bit, ==,
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(one << T::value) );
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BOOST_MPL_ASSERT_RELATION( boost::high_bit_mask_t<T::value>::high_bit_fast,
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==, (one << T::value) );
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}
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// Check the bit-masks of a block of low-valued bits
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BOOST_AUTO_TEST_CASE_TEMPLATE( low_bits_mask_test, T, low_bit_lengths )
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{
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// One can express (2^x - 1) in two ways
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// 1. (1 << x) - 1
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// 2. (1 << (x-1)) | ((1 << (x-1)) - 1)
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// Since unsigneds have modulo arithmetic, [1] gives the right answer even
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// when x is the number of bits in the register. However, that last case
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// gives warnings about the sole bit flowing past the register. Applying
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// distributive property backwards gives [2], which works without overflow.
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BOOST_MPL_ASSERT_RELATION( boost::low_bits_mask_t<T::value>::sig_bits, ==,
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(one << ( T::value - 1u )) | (( one << (T::value - 1u) ) - 1u) );
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BOOST_MPL_ASSERT_RELATION( boost::low_bits_mask_t<T::value>::sig_bits_fast,
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==, (one << ( T::value - 1u )) | (( one << (T::value - 1u) ) - 1u) );
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}
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BOOST_AUTO_TEST_SUITE_END()
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// Verification of bugs and their fixes
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BOOST_AUTO_TEST_SUITE( bug_fix_tests )
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BOOST_AUTO_TEST_SUITE_END()
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