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Diffstat (limited to 'primedev/thirdparty/spdlog/details/circular_q.h')
-rw-r--r-- | primedev/thirdparty/spdlog/details/circular_q.h | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/primedev/thirdparty/spdlog/details/circular_q.h b/primedev/thirdparty/spdlog/details/circular_q.h new file mode 100644 index 00000000..1f2712e7 --- /dev/null +++ b/primedev/thirdparty/spdlog/details/circular_q.h @@ -0,0 +1,141 @@ +// Copyright(c) 2015-present, Gabi Melman & spdlog contributors. +// Distributed under the MIT License (http://opensource.org/licenses/MIT) + +// circular q view of std::vector. +#pragma once + +#include <vector> +#include <cassert> + +namespace spdlog { +namespace details { +template<typename T> +class circular_q +{ + size_t max_items_ = 0; + typename std::vector<T>::size_type head_ = 0; + typename std::vector<T>::size_type tail_ = 0; + size_t overrun_counter_ = 0; + std::vector<T> v_; + +public: + using value_type = T; + + // empty ctor - create a disabled queue with no elements allocated at all + circular_q() = default; + + explicit circular_q(size_t max_items) + : max_items_(max_items + 1) // one item is reserved as marker for full q + , v_(max_items_) + {} + + circular_q(const circular_q &) = default; + circular_q &operator=(const circular_q &) = default; + + // move cannot be default, + // since we need to reset head_, tail_, etc to zero in the moved object + circular_q(circular_q &&other) SPDLOG_NOEXCEPT + { + copy_moveable(std::move(other)); + } + + circular_q &operator=(circular_q &&other) SPDLOG_NOEXCEPT + { + copy_moveable(std::move(other)); + return *this; + } + + // push back, overrun (oldest) item if no room left + void push_back(T &&item) + { + if (max_items_ > 0) + { + v_[tail_] = std::move(item); + tail_ = (tail_ + 1) % max_items_; + + if (tail_ == head_) // overrun last item if full + { + head_ = (head_ + 1) % max_items_; + ++overrun_counter_; + } + } + } + + // Return reference to the front item. + // If there are no elements in the container, the behavior is undefined. + const T &front() const + { + return v_[head_]; + } + + T &front() + { + return v_[head_]; + } + + // Return number of elements actually stored + size_t size() const + { + if (tail_ >= head_) + { + return tail_ - head_; + } + else + { + return max_items_ - (head_ - tail_); + } + } + + // Return const reference to item by index. + // If index is out of range 0…size()-1, the behavior is undefined. + const T &at(size_t i) const + { + assert(i < size()); + return v_[(head_ + i) % max_items_]; + } + + // Pop item from front. + // If there are no elements in the container, the behavior is undefined. + void pop_front() + { + head_ = (head_ + 1) % max_items_; + } + + bool empty() const + { + return tail_ == head_; + } + + bool full() const + { + // head is ahead of the tail by 1 + if (max_items_ > 0) + { + return ((tail_ + 1) % max_items_) == head_; + } + return false; + } + + size_t overrun_counter() const + { + return overrun_counter_; + } + +private: + // copy from other&& and reset it to disabled state + void copy_moveable(circular_q &&other) SPDLOG_NOEXCEPT + { + max_items_ = other.max_items_; + head_ = other.head_; + tail_ = other.tail_; + overrun_counter_ = other.overrun_counter_; + v_ = std::move(other.v_); + + // put &&other in disabled, but valid state + other.max_items_ = 0; + other.head_ = other.tail_ = 0; + other.overrun_counter_ = 0; + } +}; +} // namespace details +} // namespace spdlog |