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Add tests for narrow_cast

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This commit is contained in:
Christian Mazakas
2022-12-08 12:25:27 -08:00
parent eb33ad3e3f
commit 8b14b7cddc
2 changed files with 108 additions and 0 deletions
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1
test/Jamfile.v2
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@ -95,6 +95,7 @@ run exception/rehash_exception_tests.cpp ;
run exception/swap_exception_tests.cpp : : : <define>BOOST_UNORDERED_SWAP_METHOD=2 ;
run exception/merge_exception_tests.cpp ;
run unordered/narrow_cast_tests.cpp ;
run quick.cpp ;
import ../../config/checks/config : requires ;

107
test/unordered/narrow_cast_tests.cpp Normal file
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@ -0,0 +1,107 @@
// Copyright 2022 Christian Mazakas
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/unordered/detail/narrow_cast.hpp>
#include <boost/core/lightweight_test.hpp>
#include <boost/cstdint.hpp>
// want to prove that for the wider type, the higher bits of the value
// represenation don't affect the results of the narrowing, which in this case
// is masking out the high bits when comapred to the narrow type
static void signed_integral_narrowing()
{
// test positive range, fits
// [0, 127]
for (boost::int32_t i = 0x00; i < 0x80; ++i) {
boost::int8_t k = (boost::int8_t)i;
BOOST_TEST_GE(k, 0);
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(i), k);
}
// test positive range, doesn't fit
// [0xff00, 0xff7f]
for (boost::int32_t i = 0x00; i < 0x80; ++i) {
boost::int32_t j = i + 0xff00;
boost::int8_t k = (boost::int8_t)i;
BOOST_TEST_GE(k, 0);
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(j), k);
}
// test negative range, fits
// [-128, -1]
for (boost::int32_t i = 0x00; i < 0x80; ++i) {
boost::int32_t j = i + (boost::int32_t)0xffffff80;
boost::int8_t k = (boost::int8_t)j;
BOOST_TEST_LT(j, 0);
BOOST_TEST_LT(k, 0);
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(j), k);
}
// test negative range, doesn't fit
for (boost::int32_t i = 0x00; i < 0x80; ++i) {
boost::int32_t j = i + (boost::int32_t)0x80000000;
boost::int8_t k = (boost::int8_t)(i);
BOOST_TEST_LT(j, 0);
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(j), k);
}
for (boost::int32_t i = 0x00; i < 0x100; ++i) {
boost::int32_t j = (boost::int32_t)0x80ff0000 + i;
BOOST_TEST_LT(j, 0);
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(j),
(boost::int8_t)i);
}
// test special values
{
boost::int32_t x = 0xff;
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(x), -1);
}
{
boost::int32_t x = (boost::int32_t)0xffffff00;
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(x),
(boost::int8_t)0x00);
}
{
boost::int32_t x = (boost::int32_t)0xffffff7f;
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(x),
(boost::int8_t)0x7f);
}
{
boost::int32_t x = (boost::int32_t)0xffffffff;
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::int8_t>(x),
(boost::int8_t)-1);
}
}
static void unsigned_integral_narrowing()
{
// test range: [0x00, 0xff]
for (boost::uint32_t i = 0x00; i < 0x100; ++i) {
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::uint8_t>(i),
(boost::uint8_t)(i & 0xff));
}
// test range: [0xffffff00, 0xffffffff]
boost::uint32_t i = 0xffffff00;
for (; i < 0xffffffff; ++i) {
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::uint8_t>(i),
(boost::uint8_t)(i & 0xff));
}
BOOST_TEST_EQ(boost::unordered::detail::narrow_cast<boost::uint8_t>(i),
(boost::uint8_t)(i & 0xff));
}
int main()
{
signed_integral_narrowing();
unsigned_integral_narrowing();
return boost::report_errors();
}