diff options
Diffstat (limited to 'src/prevector.h')
| -rw-r--r-- | src/prevector.h | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/src/prevector.h b/src/prevector.h index f4ece738a8..6d690e7f96 100644 --- a/src/prevector.h +++ b/src/prevector.h @@ -15,7 +15,6 @@ #include <type_traits> #include <utility> -#pragma pack(push, 1) /** Implements a drop-in replacement for std::vector<T> which stores up to N * elements directly (without heap allocation). The types Size and Diff are * used to store element counts, and can be any unsigned + signed type. @@ -147,14 +146,20 @@ public: }; private: - size_type _size = 0; +#pragma pack(push, 1) union direct_or_indirect { char direct[sizeof(T) * N]; struct { - size_type capacity; char* indirect; + size_type capacity; }; - } _union = {}; + }; +#pragma pack(pop) + alignas(char*) direct_or_indirect _union = {}; + size_type _size = 0; + + static_assert(alignof(char*) % alignof(size_type) == 0 && sizeof(char*) % alignof(size_type) == 0, "size_type cannot have more restrictive alignment requirement than pointer"); + static_assert(alignof(char*) % alignof(T) == 0, "value_type T cannot have more restrictive alignment requirement than pointer"); T* direct_ptr(difference_type pos) { return reinterpret_cast<T*>(_union.direct) + pos; } const T* direct_ptr(difference_type pos) const { return reinterpret_cast<const T*>(_union.direct) + pos; } @@ -419,15 +424,20 @@ public: return first; } - void push_back(const T& value) { + template<typename... Args> + void emplace_back(Args&&... args) { size_type new_size = size() + 1; if (capacity() < new_size) { change_capacity(new_size + (new_size >> 1)); } - new(item_ptr(size())) T(value); + new(item_ptr(size())) T(std::forward<Args>(args)...); _size++; } + void push_back(const T& value) { + emplace_back(value); + } + void pop_back() { erase(end() - 1, end()); } @@ -523,6 +533,5 @@ public: return item_ptr(0); } }; -#pragma pack(pop) #endif // BITCOIN_PREVECTOR_H |