CoopAllTheThings/tests/audio_ring_test.cpp

// In-process unit test for the shared audio ring (coop/audio_ring.hpp). No
// shared memory, no hook, no audio device: it exercises the lock-free SPSC
// push/pop, wrap-around, the format handshake, and the overrun/drop policy in a
// single process. Exits 0 on pass, 1 on failure.

#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <vector>

#include "coop/audio_ring.hpp"

using namespace coop;

namespace {

int g_failures = 0;

void check(bool ok, const char* what)
{
	if (!ok) {
		std::printf("  FAIL: %s\n", what);
		++g_failures;
	}
}

// Allocate a ring of `capacity` data bytes in a plain heap buffer (placement-new
// the header so its atomics are constructed) and return it ready to use.
AudioRingHeader* make_ring(std::vector<std::uint8_t>& storage, std::uint32_t capacity)
{
	storage.assign(audio_ring_total_size(capacity), 0);
	auto* h = new (storage.data()) AudioRingHeader();
	audio_ring_init(*h, capacity);
	return h;
}

} // namespace

int main()
{
	// --- Validity + format handshake. ---
	{
		std::vector<std::uint8_t> storage;
		AudioRingHeader* h = make_ring(storage, 4096);
		check(audio_ring_valid(*h), "freshly inited ring is valid");
		check(!audio_ring_format_ready(*h), "format not ready before set");
		audio_ring_set_format(*h, 48000, 2, 32, 3 /*IEEE_FLOAT*/, 8);
		check(audio_ring_format_ready(*h), "format ready after set");
		check(h->sample_rate == 48000 && h->channels == 2 && h->bits == 32 && h->format_tag == 3 && h->block_align == 8,
		      "format fields round-trip");
	}

	// --- Basic push/pop integrity. ---
	{
		std::vector<std::uint8_t> storage;
		AudioRingHeader* h = make_ring(storage, 4096);

		std::uint8_t src[256];
		for (int i = 0; i < 256; ++i) {
			src[i] = static_cast<std::uint8_t>(i);
		}
		check(audio_ring_push(*h, src, sizeof(src), 32), "push 256 bytes");
		check(audio_ring_available(*h) == sizeof(src), "available == pushed");
		check(h->frames_produced.load() == 32, "frames_produced tracked");

		std::uint8_t dst[256] = {};
		check(audio_ring_pop(*h, dst, sizeof(dst)) == sizeof(src), "pop returns all bytes");
		check(std::memcmp(src, dst, sizeof(src)) == 0, "popped bytes match pushed");
		check(audio_ring_available(*h) == 0, "ring empty after drain");
	}

	// --- Wrap-around: keep pushing/popping past capacity to force a split copy. ---
	{
		const std::uint32_t cap = 1024;
		std::vector<std::uint8_t> storage;
		AudioRingHeader* h = make_ring(storage, cap);

		std::uint8_t counter = 0;
		std::uint8_t expect = 0;
		const std::uint32_t chunk = 300; // not a divisor of cap, so offsets drift across the seam
		for (int iter = 0; iter < 50; ++iter) {
			std::uint8_t buf[300];
			for (std::uint32_t i = 0; i < chunk; ++i) {
				buf[i] = counter++;
			}
			check(audio_ring_push(*h, buf, chunk, chunk), "wrap push fits");

			std::uint8_t out[300] = {};
			check(audio_ring_pop(*h, out, chunk) == chunk, "wrap pop full chunk");
			bool ok = true;
			for (std::uint32_t i = 0; i < chunk; ++i) {
				ok = ok && out[i] == expect++;
			}
			check(ok, "wrap data integrity across the ring seam");
		}
	}

	// --- Overrun: a packet that doesn't fit is dropped whole, bumping overruns. ---
	{
		const std::uint32_t cap = 512;
		std::vector<std::uint8_t> storage;
		AudioRingHeader* h = make_ring(storage, cap);

		std::vector<std::uint8_t> half(cap / 2, 0xAB);
		check(audio_ring_push(*h, half.data(), cap / 2, 1), "first half fits");
		check(audio_ring_push(*h, half.data(), cap / 2, 1), "second half fills ring");
		check(audio_ring_available(*h) == cap, "ring full");

		std::vector<std::uint8_t> more(16, 0xCD);
		check(!audio_ring_push(*h, more.data(), 16, 1), "push into full ring rejected");
		check(h->overruns.load() == 1, "overrun counted");
		check(audio_ring_available(*h) == cap, "rejected push left ring untouched");

		// Draining makes room again; subsequent pushes succeed.
		std::vector<std::uint8_t> drain(cap, 0);
		check(audio_ring_pop(*h, drain.data(), cap) == cap, "drain full ring");
		check(audio_ring_push(*h, more.data(), 16, 1), "push succeeds after drain");
		check(h->overruns.load() == 1, "overruns not bumped on success");
	}

	// --- Seam interaction: with the write head near the end, a wrapping push fits while an
	//     over-capacity wrapping push is dropped whole (the overrun + wrap split happening together). ---
	{
		const std::uint32_t cap = 512;
		std::vector<std::uint8_t> storage;
		AudioRingHeader* h = make_ring(storage, cap);

		// Advance the write head near the end so subsequent writes wrap the buffer seam.
		std::vector<std::uint8_t> pre(400, 0x55);
		check(audio_ring_push(*h, pre.data(), 400, 1), "seam: prime to advance the write head");
		std::vector<std::uint8_t> sink(400, 0);
		check(audio_ring_pop(*h, sink.data(), 400) == 400, "seam: drain it (head now near the end)");
		check(audio_ring_available(*h) == 0, "seam: empty again, write head near the seam");

		// A 200-byte push now splits across the seam; it fits, so the data must survive the split.
		std::vector<std::uint8_t> wrap(200);
		for (std::uint32_t i = 0; i < 200; ++i) {
			wrap[i] = static_cast<std::uint8_t>(i);
		}
		check(audio_ring_push(*h, wrap.data(), 200, 1), "seam: a wrapping push that fits is accepted");
		check(audio_ring_available(*h) == 200, "seam: 200 bytes present after the wrapping push");

		// A 400-byte push would also wrap but can't fit (free = 312) -> dropped whole, overruns++.
		const std::uint64_t before = h->overruns.load();
		std::vector<std::uint8_t> big(400, 0xEE);
		check(!audio_ring_push(*h, big.data(), 400, 1), "seam: an over-capacity wrapping push is rejected whole");
		check(h->overruns.load() == before + 1, "seam: overrun counted");
		check(audio_ring_available(*h) == 200, "seam: rejected wrapping push left the ring untouched");

		// Pop the wrapped payload back and verify integrity across the seam.
		std::vector<std::uint8_t> out(200, 0);
		check(audio_ring_pop(*h, out.data(), 200) == 200, "seam: pop the wrapped payload");
		bool ok = true;
		for (std::uint32_t i = 0; i < 200; ++i) {
			ok = ok && out[i] == static_cast<std::uint8_t>(i);
		}
		check(ok, "seam: wrapping push/pop preserved data across the buffer seam");
	}

	std::printf(g_failures == 0 ? "AUDIO RING TEST PASS\n" : "AUDIO RING TEST FAILED (%d)\n", g_failures);
	return g_failures == 0 ? 0 : 1;
}