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author | Wladimir J. van der Laan <laanwj@protonmail.com> | 2020-04-30 11:16:39 +0200 |
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committer | Wladimir J. van der Laan <laanwj@protonmail.com> | 2020-04-30 11:16:56 +0200 |
commit | 35ef3c15ef8263b79c6e8f002ceab270f08cd5a5 (patch) | |
tree | 04c9d58f6e5f7416e339f395f7684cf0bb80309e /src | |
parent | 63d5ed2fc45846ebab760764a3c07b1062212b3b (diff) | |
parent | c31cbe7cfefc18123eb85ffb2ce509748435efde (diff) | |
download | bitcoin-35ef3c15ef8263b79c6e8f002ceab270f08cd5a5.tar.xz |
Merge #18591: Add C++17 build to Travis
c31cbe7cfefc18123eb85ffb2ce509748435efde Add C++17 test to Travis (Pieter Wuille)
7829685e27aae25efb32e07368175c8f664b2218 Add configure option for c++17 (Pieter Wuille)
0fbde488b24f62b4bbbde216647941dcac65c81a Support conversion between Spans of compatible types (Pieter Wuille)
7cbfebbf3df0d26f518811e0bfb7abf270c83e37 Update ax_cxx_compile_stdcxx.m4 (Pieter Wuille)
Pull request description:
This adds a `--enable-c++17` option to the configure script, fixes the only C++17 incompatibility (with a commit taken from #18468), and adds a Travis test for it.
This is all off by default, and release builds remain C++11.
It implements the first step of the plan in https://github.com/bitcoin/bitcoin/issues/16684.
ACKs for top commit:
elichai:
tACK c31cbe7cfefc18123eb85ffb2ce509748435efde
practicalswift:
Tested ACK c31cbe7cfefc18123eb85ffb2ce509748435efde
hebasto:
ACK c31cbe7cfefc18123eb85ffb2ce509748435efde, tested on Linux Mint 19.3 both C++11 and C++17 modes. Compiled and passed tests locally.
Tree-SHA512: a4b00776dbceef9c12abbb404c6bcd48f7916ce24c8c7a14116355f64e817578b7fcddbedd5ce435322319d1e4de43429b68553f4d96d970c308fe3e3e59b9d1
Diffstat (limited to 'src')
-rw-r--r-- | src/span.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/span.h b/src/span.h index 664ea8d4c6..73b37e35f3 100644 --- a/src/span.h +++ b/src/span.h @@ -25,6 +25,23 @@ public: 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) {} + /** Implicit conversion of spans between compatible types. + * + * Specifically, if a pointer to an array of type O can be implicitly converted to a pointer to an array of type + * C, then permit implicit conversion of Span<O> to Span<C>. This matches the behavior of the corresponding + * C++20 std::span constructor. + * + * For example this means that a Span<T> can be converted into a Span<const T>. + */ + template <typename O, typename std::enable_if<std::is_convertible<O (*)[], C (*)[]>::value, int>::type = 0> + constexpr Span(const Span<O>& other) noexcept : m_data(other.m_data), m_size(other.m_size) {} + + /** Default copy constructor. */ + constexpr Span(const Span&) noexcept = default; + + /** Default assignment operator. */ + Span& operator=(const Span& other) noexcept = default; + 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; } @@ -44,6 +61,8 @@ public: 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); } + + template <typename O> friend class Span; }; /** Create a span to a container exposing data() and size(). |