diff options
Diffstat (limited to 'src/span.h')
-rw-r--r-- | src/span.h | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/span.h b/src/span.h index 77de059fa6..664ea8d4c6 100644 --- a/src/span.h +++ b/src/span.h @@ -1,4 +1,4 @@ -// Copyright (c) 2018 The Bitcoin Core developers +// Copyright (c) 2018-2020 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. @@ -8,6 +8,7 @@ #include <type_traits> #include <cstddef> #include <algorithm> +#include <assert.h> /** A Span is an object that can refer to a contiguous sequence of objects. * @@ -27,6 +28,8 @@ public: 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 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]; } @@ -57,4 +60,15 @@ 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()); } +/** Pop the last element off a span, and return a reference to that element. */ +template <typename T> +T& SpanPopBack(Span<T>& span) +{ + size_t size = span.size(); + assert(size > 0); + T& back = span[size - 1]; + span = Span<T>(span.data(), size - 1); + return back; +} + #endif |