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Make Span size type unsigned
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This matches a change in the C++20 std::span proposal.
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sipa authored and furszy committed Jul 6, 2021
1 parent 17118e1 commit 33d5297
Showing 1 changed file with 9 additions and 8 deletions.
17 changes: 9 additions & 8 deletions src/span.h
Original file line number Diff line number Diff line change
Expand Up @@ -18,11 +18,12 @@ template<typename C>
class Span
{
C* m_data;
std::ptrdiff_t m_size;
std::size_t m_size;

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, std::size_t size) noexcept : m_data(data), m_size(size) {}

constexpr Span(C* data, C* end) noexcept : m_data(data), m_size(end - data) {}

/** Implicit conversion of spans between compatible types.
Expand All @@ -47,13 +48,13 @@ class Span
constexpr C* end() const noexcept { return m_data + m_size; }
constexpr C& front() const noexcept { return m_data[0]; }
constexpr C& back() const noexcept { return m_data[m_size - 1]; }
constexpr std::ptrdiff_t size() const noexcept { return m_size; }
constexpr C& operator[](std::ptrdiff_t pos) const noexcept { return m_data[pos]; }
constexpr std::size_t size() const noexcept { return m_size; }
constexpr C& operator[](std::size_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); }
constexpr Span<C> subspan(std::size_t offset) const noexcept { return Span<C>(m_data + offset, m_size - offset); }
constexpr Span<C> subspan(std::size_t offset, std::size_t count) const noexcept { return Span<C>(m_data + offset, count); }
constexpr Span<C> first(std::size_t count) const noexcept { return Span<C>(m_data, count); }
constexpr Span<C> last(std::size_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); }
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