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Henrik RydgårdandClaude Opus 5.5
1e5a54e7b5
Android is about to need the same one. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
72 lines
2.5 KiB
C++
72 lines
2.5 KiB
C++
// Copyright (c) 2012- PPSSPP Project.
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, version 2.0 or later versions.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License 2.0 for more details.
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// A copy of the GPL 2.0 should have been included with the program.
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// If not, see http://www.gnu.org/licenses/
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// Official git repository and contact information can be found at
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// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
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#pragma once
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#include <algorithm>
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#include <atomic>
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#include <cstdint>
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// Hands 16-bit samples from one producer thread (a host audio callback) to one consumer thread.
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// Lock-free and allocation-free, so it's safe to push from a real-time callback. Input that
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// doesn't fit is dropped.
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template <uint32_t SIZE>
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class SampleRing {
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static_assert((SIZE & (SIZE - 1)) == 0, "SIZE must be a power of two");
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public:
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// Producer. Null samples means silence.
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void Push(const int16_t *samples, uint32_t count) {
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const uint32_t write = writePos_.load(std::memory_order_relaxed);
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const uint32_t read = readPos_.load(std::memory_order_acquire);
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count = std::min(count, SIZE - (write - read));
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for (uint32_t i = 0; i < count; i++) {
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ring_[(write + i) & (SIZE - 1)] = samples ? samples[i] : 0;
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}
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writePos_.store(write + count, std::memory_order_release);
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}
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// Consumer. Calls func(const int16_t *samples, uint32_t count) for what's buffered, in up to
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// two pieces if it wraps around the end of the ring.
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template <class F>
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void Drain(F func) {
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const uint32_t read = readPos_.load(std::memory_order_relaxed);
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const uint32_t write = writePos_.load(std::memory_order_acquire);
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const uint32_t count = write - read;
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if (count == 0) {
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return;
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}
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const uint32_t start = read & (SIZE - 1);
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const uint32_t first = std::min(count, SIZE - start);
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func(&ring_[start], first);
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if (count > first) {
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func(&ring_[0], count - first);
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}
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readPos_.store(read + count, std::memory_order_release);
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}
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// Consumer. Drops whatever is buffered.
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void Clear() {
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readPos_.store(writePos_.load(std::memory_order_acquire), std::memory_order_release);
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}
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private:
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int16_t ring_[SIZE];
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std::atomic<uint32_t> writePos_{0};
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std::atomic<uint32_t> readPos_{0};
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};
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