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-rw-r--r--contrib/epee/include/span.h46
-rw-r--r--tests/unit_tests/epee_utils.cpp57
2 files changed, 96 insertions, 7 deletions
diff --git a/contrib/epee/include/span.h b/contrib/epee/include/span.h
index 452cc088f..174915ecf 100644
--- a/contrib/epee/include/span.h
+++ b/contrib/epee/include/span.h
@@ -28,6 +28,7 @@
#pragma once
+#include <algorithm>
#include <cstdint>
#include <memory>
#include <type_traits>
@@ -52,11 +53,15 @@ namespace epee
template<typename T>
class span
{
- /* Supporting class types is tricky - the {ptr,len} constructor will allow
- derived-to-base conversions. This is NOT desireable because an array of
- derived types is not an array of base types. It is possible to handle
- this case, implement when/if needed. */
- static_assert(!std::is_class<T>(), "no class types are currently allowed");
+ template<typename U>
+ static constexpr bool safe_conversion() noexcept
+ {
+ // Allow exact matches or `T*` -> `const T*`.
+ using with_const = typename std::add_const<U>::type;
+ return std::is_same<T, U>() ||
+ (std::is_const<T>() && std::is_same<T, with_const>());
+ }
+
public:
using value_type = T;
using size_type = std::size_t;
@@ -71,7 +76,9 @@ namespace epee
constexpr span() noexcept : ptr(nullptr), len(0) {}
constexpr span(std::nullptr_t) noexcept : span() {}
- constexpr span(T* const src_ptr, const std::size_t count) noexcept
+ //! Prevent derived-to-base conversions; invalid in this context.
+ template<typename U, typename = typename std::enable_if<safe_conversion<U>()>::type>
+ constexpr span(U* const src_ptr, const std::size_t count) noexcept
: ptr(src_ptr), len(count) {}
//! Conversion from C-array. Prevents common bugs with sizeof + arrays.
@@ -81,6 +88,16 @@ namespace epee
constexpr span(const span&) noexcept = default;
span& operator=(const span&) noexcept = default;
+ /*! Try to remove `amount` elements from beginning of span.
+ \return Number of elements removed. */
+ std::size_t remove_prefix(std::size_t amount) noexcept
+ {
+ amount = std::min(len, amount);
+ ptr += amount;
+ len -= amount;
+ return amount;
+ }
+
constexpr iterator begin() const noexcept { return ptr; }
constexpr const_iterator cbegin() const noexcept { return ptr; }
@@ -105,6 +122,14 @@ namespace epee
return {src.data(), src.size()};
}
+ //! \return `span<T::value_type>` from a STL compatible `src`.
+ template<typename T>
+ constexpr span<typename T::value_type> to_mut_span(T& src)
+ {
+ // compiler provides diagnostic if size() is not size_t.
+ return {src.data(), src.size()};
+ }
+
template<typename T>
constexpr bool has_padding() noexcept
{
@@ -127,4 +152,13 @@ namespace epee
static_assert(!has_padding<T>(), "source type may have padding");
return {reinterpret_cast<const std::uint8_t*>(std::addressof(src)), sizeof(T)};
}
+
+ //! \return `span<std::uint8_t>` which represents the bytes at `&src`.
+ template<typename T>
+ span<std::uint8_t> as_mut_byte_span(T& src) noexcept
+ {
+ static_assert(!std::is_empty<T>(), "empty types will not work -> sizeof == 1");
+ static_assert(!has_padding<T>(), "source type may have padding");
+ return {reinterpret_cast<std::uint8_t*>(std::addressof(src)), sizeof(T)};
+ }
}
diff --git a/tests/unit_tests/epee_utils.cpp b/tests/unit_tests/epee_utils.cpp
index 3474000d8..c2b0b7647 100644
--- a/tests/unit_tests/epee_utils.cpp
+++ b/tests/unit_tests/epee_utils.cpp
@@ -166,12 +166,17 @@ TEST(Span, Traits)
TEST(Span, MutableConstruction)
{
struct no_conversion{};
+ struct inherited : no_conversion {};
EXPECT_TRUE(std::is_constructible<epee::span<char>>());
EXPECT_TRUE((std::is_constructible<epee::span<char>, char*, std::size_t>()));
EXPECT_FALSE((std::is_constructible<epee::span<char>, const char*, std::size_t>()));
EXPECT_FALSE((std::is_constructible<epee::span<char>, unsigned char*, std::size_t>()));
+ EXPECT_TRUE(std::is_constructible<epee::span<no_conversion>>());
+ EXPECT_TRUE((std::is_constructible<epee::span<no_conversion>, no_conversion*, std::size_t>()));
+ EXPECT_FALSE((std::is_constructible<epee::span<no_conversion>, inherited*, std::size_t>()));
+
EXPECT_TRUE((can_construct<epee::span<char>, std::nullptr_t>()));
EXPECT_TRUE((can_construct<epee::span<char>, char(&)[1]>()));
@@ -193,12 +198,19 @@ TEST(Span, MutableConstruction)
TEST(Span, ImmutableConstruction)
{
struct no_conversion{};
+ struct inherited : no_conversion {};
EXPECT_TRUE(std::is_constructible<epee::span<const char>>());
EXPECT_TRUE((std::is_constructible<epee::span<const char>, char*, std::size_t>()));
EXPECT_TRUE((std::is_constructible<epee::span<const char>, const char*, std::size_t>()));
EXPECT_FALSE((std::is_constructible<epee::span<const char>, unsigned char*, std::size_t>()));
+ EXPECT_TRUE(std::is_constructible<epee::span<const no_conversion>>());
+ EXPECT_TRUE((std::is_constructible<epee::span<const no_conversion>, const no_conversion*, std::size_t>()));
+ EXPECT_TRUE((std::is_constructible<epee::span<const no_conversion>, no_conversion*, std::size_t>()));
+ EXPECT_FALSE((std::is_constructible<epee::span<const no_conversion>, const inherited*, std::size_t>()));
+ EXPECT_FALSE((std::is_constructible<epee::span<const no_conversion>, inherited*, std::size_t>()));
+
EXPECT_FALSE((can_construct<epee::span<const char>, std::string>()));
EXPECT_FALSE((can_construct<epee::span<const char>, std::vector<char>>()));
EXPECT_FALSE((can_construct<epee::span<const char>, const std::vector<char>>()));
@@ -231,7 +243,6 @@ TEST(Span, NoExcept)
const epee::span<char> clvalue(data);
EXPECT_TRUE(noexcept(epee::span<char>()));
EXPECT_TRUE(noexcept(epee::span<char>(nullptr)));
- EXPECT_TRUE(noexcept(epee::span<char>(nullptr, 0)));
EXPECT_TRUE(noexcept(epee::span<char>(data)));
EXPECT_TRUE(noexcept(epee::span<char>(lvalue)));
EXPECT_TRUE(noexcept(epee::span<char>(clvalue)));
@@ -284,6 +295,25 @@ TEST(Span, Writing)
EXPECT_TRUE(boost::range::equal(expected, span));
}
+TEST(Span, RemovePrefix)
+{
+ const std::array<unsigned, 4> expected{0, 1, 2, 3};
+ auto span = epee::to_span(expected);
+
+ EXPECT_EQ(expected.begin(), span.begin());
+ EXPECT_EQ(expected.end(), span.end());
+
+ EXPECT_EQ(2u, span.remove_prefix(2));
+ EXPECT_EQ(expected.begin() + 2, span.begin());
+ EXPECT_EQ(expected.end(), span.end());
+
+ EXPECT_EQ(2u, span.remove_prefix(3));
+ EXPECT_EQ(span.begin(), span.end());
+ EXPECT_EQ(expected.end(), span.begin());
+
+ EXPECT_EQ(0u, span.remove_prefix(100));
+}
+
TEST(Span, ToByteSpan)
{
const char expected[] = {56, 44, 11, 5};
@@ -318,6 +348,30 @@ TEST(Span, AsByteSpan)
);
}
+TEST(Span, AsMutByteSpan)
+{
+ struct some_pod { char value[4]; };
+ some_pod actual {};
+
+ auto span = epee::as_mut_byte_span(actual);
+ boost::range::iota(span, 1);
+ EXPECT_TRUE(
+ boost::range::equal(
+ std::array<unsigned char, 4>{{1, 2, 3, 4}}, actual.value
+ )
+ );
+}
+
+TEST(Span, ToMutSpan)
+{
+ std::vector<unsigned> mut;
+ mut.resize(4);
+
+ auto span = epee::to_mut_span(mut);
+ boost::range::iota(span, 1);
+ EXPECT_EQ((std::vector<unsigned>{1, 2, 3, 4}), mut);
+}
+
TEST(ToHex, String)
{
EXPECT_TRUE(epee::to_hex::string(nullptr).empty());
@@ -330,6 +384,7 @@ TEST(ToHex, String)
EXPECT_EQ(
std_to_hex(all_bytes), epee::to_hex::string(epee::to_span(all_bytes))
);
+
}
TEST(ToHex, Array)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 17:58:35 +0000