diff options
Diffstat (limited to 'src/span.h')
| -rw-r--r-- | src/span.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/span.h b/src/span.h index 707fc21918..77de059fa6 100644 --- a/src/span.h +++ b/src/span.h @@ -7,6 +7,7 @@ #include <type_traits> #include <cstddef> +#include <algorithm> /** A Span is an object that can refer to a contiguous sequence of objects. * @@ -21,9 +22,25 @@ class Span public: constexpr Span() noexcept : m_data(nullptr), m_size(0) {} constexpr Span(C* data, std::ptrdiff_t size) noexcept : m_data(data), m_size(size) {} + constexpr Span(C* data, C* end) noexcept : m_data(data), m_size(end - data) {} constexpr C* data() const noexcept { return m_data; } + constexpr C* begin() const noexcept { return m_data; } + constexpr C* end() const noexcept { return m_data + m_size; } constexpr std::ptrdiff_t size() const noexcept { return m_size; } + constexpr C& operator[](std::ptrdiff_t pos) const noexcept { return m_data[pos]; } + + constexpr Span<C> subspan(std::ptrdiff_t offset) const noexcept { return Span<C>(m_data + offset, m_size - offset); } + constexpr Span<C> subspan(std::ptrdiff_t offset, std::ptrdiff_t count) const noexcept { return Span<C>(m_data + offset, count); } + constexpr Span<C> first(std::ptrdiff_t count) const noexcept { return Span<C>(m_data, count); } + constexpr Span<C> last(std::ptrdiff_t count) const noexcept { return Span<C>(m_data + m_size - count, count); } + + friend constexpr bool operator==(const Span& a, const Span& b) noexcept { return a.size() == b.size() && std::equal(a.begin(), a.end(), b.begin()); } + friend constexpr bool operator!=(const Span& a, const Span& b) noexcept { return !(a == b); } + friend constexpr bool operator<(const Span& a, const Span& b) noexcept { return std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end()); } + friend constexpr bool operator<=(const Span& a, const Span& b) noexcept { return !(b < a); } + friend constexpr bool operator>(const Span& a, const Span& b) noexcept { return (b < a); } + friend constexpr bool operator>=(const Span& a, const Span& b) noexcept { return !(a < b); } }; /** Create a span to a container exposing data() and size(). @@ -34,6 +51,9 @@ public: * * std::span will have a constructor that implements this functionality directly. */ +template<typename A, int N> +constexpr Span<A> MakeSpan(A (&a)[N]) { return Span<A>(a, N); } + template<typename V> constexpr Span<typename std::remove_pointer<decltype(std::declval<V>().data())>::type> MakeSpan(V& v) { return Span<typename std::remove_pointer<decltype(std::declval<V>().data())>::type>(v.data(), v.size()); } |