Last active
January 21, 2023 21:08
-
-
Save SteveBronder/e881e4b350e3f5893c2792ed5968da7f to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #include <atomic> | |
| #include <cassert> | |
| #include <iostream> | |
| #include <memory> | |
| #include <vector> | |
| #include <array> | |
| #define NO_INLINE __attribute__((noinline)) | |
| #define ALWAYS_INLINE __attribute__((always_inline)) | |
| #define likely(x) __builtin_expect((x), 1) | |
| #define unlikely(x) __builtin_expect((x), 0) | |
| template <std::size_t N> | |
| struct ringbuffer { | |
| std::array<int, N> data_{}; | |
| // tail: the point at which the consumer finds the next item in the buffer | |
| alignas(64) std::atomic<size_t> readIdx_{0}; | |
| alignas(64) size_t writeIdxCached_{0}; | |
| // head: the point at which the producer inserts items into the buffer. | |
| alignas(64) std::atomic<size_t> writeIdx_{0}; | |
| alignas(64) size_t readIdxCached_{0}; | |
| ALWAYS_INLINE inline bool push(int val) noexcept { | |
| const auto writeIdx = writeIdx_.load(std::memory_order_relaxed); | |
| auto nextWriteIdx = (writeIdx + 1) & (N - 1); | |
| if (unlikely(nextWriteIdx == readIdxCached_)) { | |
| readIdxCached_ = readIdx_.load(std::memory_order_acquire); | |
| if (nextWriteIdx == readIdxCached_) { | |
| return false; | |
| } | |
| } | |
| data_[writeIdx] = val; | |
| writeIdx_.store(nextWriteIdx, std::memory_order_release); | |
| return true; | |
| } | |
| ALWAYS_INLINE inline bool pop(int &val) noexcept { | |
| auto const readIdx = readIdx_.load(std::memory_order_relaxed); | |
| if (unlikely(readIdx == writeIdxCached_)) { | |
| writeIdxCached_ = writeIdx_.load(std::memory_order_acquire); | |
| if (readIdx == writeIdxCached_) { | |
| return false; | |
| } | |
| } | |
| val = data_[readIdx]; | |
| auto nextReadIdx = (readIdx + 1) & (N - 1); | |
| readIdx_.store(nextReadIdx, std::memory_order_release); | |
| return true; | |
| } | |
| }; | |
| int main() { | |
| return 0; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment