para/GSL
1
0
Fork 0
mirror of https://github.com/microsoft/GSL.git synced 2025-04-01 08:56:29 -04:00
Code Issues Actions Packages Projects Releases Wiki Activity

static_assert for templated span::first/last/subspan

Browse Source 
plus more unit tests for these functions
This commit is contained in:
Werner Henze 2025-01-02 11:01:29 +01:00 committed by Werner Henze
parent b438aa9470
commit e8fa8b189d
2 changed files with 50 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/gsl/span
View File

@ -582,6 +582,8 @@ public:
template <std::size_t Count>
constexpr span<element_type, Count> first() const noexcept
{
static_assert(Count <= Extent,
"first() cannot extract more elements from a span than it contains.");
Expects(Count <= size());
return span<element_type, Count>{data(), Count};
}
@ -592,6 +594,8 @@ public:
// clang-format on
constexpr span<element_type, Count> last() const noexcept
{
static_assert(Count <= Extent,
"last() cannot extract more elements from a span than it contains.");
Expects(Count <= size());
return span<element_type, Count>{data() + (size() - Count), Count};
}
@ -603,6 +607,8 @@ public:
constexpr auto subspan() const noexcept ->
typename details::calculate_subspan_type<ElementType, Extent, Offset, Count>::type
{
static_assert(Extent >= Offset && (Count == dynamic_extent || Count <= Extent - Offset),
"subspan() cannot extract more elements from a span than it contains.");
Expects((size() >= Offset) && (Count == dynamic_extent || (Count <= size() - Offset)));
using type =
typename details::calculate_subspan_type<ElementType, Extent, Offset, Count>::type;

46
tests/span_tests.cpp
View File

@ -701,7 +701,9 @@ TEST(span_test, first)
{
span<int, 5> av = arr;
EXPECT_DEATH(av.first<6>(), expected);
#ifdef CONFIRM_COMPILATION_ERRORS
(void) av.first<6>();
#endif
EXPECT_DEATH(av.first(6), expected);
}
@ -742,7 +744,9 @@ TEST(span_test, last)
{
span<int, 5> av = arr;
EXPECT_DEATH(av.last<6>(), expected);
#ifdef CONFIRM_COMPILATION_ERRORS
(void) av.last<6>();
#endif
EXPECT_DEATH(av.last(6), expected);
}
@ -768,6 +772,9 @@ TEST(span_test, subspan)
EXPECT_TRUE((av.subspan<2, 2>().size()) == 2);
EXPECT_TRUE(decltype(av.subspan<2, 2>())::extent == 2);
EXPECT_TRUE(av.subspan(2, 2).size() == 2);
EXPECT_TRUE((av.subspan<2, 3>().size()) == 3);
EXPECT_TRUE(decltype(av.subspan<2, 3>())::extent == 3);
EXPECT_TRUE(av.subspan(2, 3).size() == 3);
}
@ -784,6 +791,10 @@ TEST(span_test, subspan)
EXPECT_TRUE(decltype(av.subspan<0, 5>())::extent == 5);
EXPECT_TRUE(av.subspan(0, 5).size() == 5);
#ifdef CONFIRM_COMPILATION_ERRORS
(void) av.subspan<0, 6>();
(void) av.subspan<1, 5>();
#endif
EXPECT_DEATH(av.subspan(0, 6), expected);
EXPECT_DEATH(av.subspan(1, 5), expected);
}
@ -793,7 +804,14 @@ TEST(span_test, subspan)
EXPECT_TRUE((av.subspan<4, 0>().size()) == 0);
EXPECT_TRUE(decltype(av.subspan<4, 0>())::extent == 0);
EXPECT_TRUE(av.subspan(4, 0).size() == 0);
EXPECT_TRUE((av.subspan<5, 0>().size()) == 0);
EXPECT_TRUE(decltype(av.subspan<5, 0>())::extent == 0);
EXPECT_TRUE(av.subspan(5, 0).size() == 0);
#ifdef CONFIRM_COMPILATION_ERRORS
(void) av.subspan<6, 0>();
#endif
EXPECT_DEATH(av.subspan(6, 0), expected);
}
@ -801,6 +819,7 @@ TEST(span_test, subspan)
span<int, 5> av = arr;
EXPECT_TRUE(av.subspan<1>().size() == 4);
EXPECT_TRUE(decltype(av.subspan<1>())::extent == 4);
EXPECT_TRUE(av.subspan(1).size() == 4);
}
{
@ -808,35 +827,58 @@ TEST(span_test, subspan)
EXPECT_TRUE((av.subspan<0, 0>().size()) == 0);
EXPECT_TRUE(decltype(av.subspan<0, 0>())::extent == 0);
EXPECT_TRUE(av.subspan(0, 0).size() == 0);
EXPECT_DEATH((av.subspan<1, 0>()), expected);
EXPECT_DEATH((av.subspan(1, 0)), expected);
}
{
span<int> av;
EXPECT_TRUE((av.subspan<0>().size()) == 0);
EXPECT_TRUE(decltype(av.subspan<0>())::extent == dynamic_extent);
EXPECT_TRUE(av.subspan(0).size() == 0);
EXPECT_DEATH(av.subspan<1>(), expected);
EXPECT_TRUE(decltype(av.subspan<1>())::extent == dynamic_extent);
EXPECT_DEATH(av.subspan(1), expected);
}
{
span<int> av = arr;
EXPECT_TRUE(av.subspan(0).size() == 5);
EXPECT_TRUE(av.subspan<0>().size() == 5);
EXPECT_TRUE(av.subspan(1).size() == 4);
EXPECT_TRUE(av.subspan<1>().size() == 4);
EXPECT_TRUE(av.subspan(4).size() == 1);
EXPECT_TRUE(av.subspan<4>().size() == 1);
EXPECT_TRUE(av.subspan(5).size() == 0);
EXPECT_TRUE(av.subspan<5>().size() == 0);
EXPECT_DEATH(av.subspan(6), expected);
EXPECT_DEATH(av.subspan<6>(), expected);
const auto av2 = av.subspan(1);
for (std::size_t i = 0; i < 4; ++i) EXPECT_TRUE(av2[i] == static_cast<int>(i) + 2);
const auto av3 = av.subspan<1>();
for (std::size_t i = 0; i < 4; ++i) EXPECT_TRUE(av3[i] == static_cast<int>(i) + 2);
}
{
span<int, 5> av = arr;
EXPECT_TRUE(av.subspan(0).size() == 5);
EXPECT_TRUE(av.subspan<0>().size() == 5);
EXPECT_TRUE(av.subspan(1).size() == 4);
EXPECT_TRUE(av.subspan<1>().size() == 4);
EXPECT_TRUE(av.subspan(4).size() == 1);
EXPECT_TRUE(av.subspan<4>().size() == 1);
EXPECT_TRUE(av.subspan(5).size() == 0);
EXPECT_TRUE(av.subspan<5>().size() == 0);
EXPECT_DEATH(av.subspan(6), expected);
#ifdef CONFIRM_COMPILATION_ERRORS
EXPECT_DEATH(av.subspan<6>(), expected);
#endif
const auto av2 = av.subspan(1);
for (std::size_t i = 0; i < 4; ++i) EXPECT_TRUE(av2[i] == static_cast<int>(i) + 2);
const auto av3 = av.subspan<1>();
for (std::size_t i = 0; i < 4; ++i) EXPECT_TRUE(av3[i] == static_cast<int>(i) + 2);
}
}