aaudio: add unit test for FIFO

Write data, read it back and verify.
Try to trigger wrap-around conditions.

Bug: 78139448
Test: this is a test
Change-Id: I4247fcf57a25c97c6ab8ce9671d0f61556ecef6a
diff --git a/media/libaaudio/tests/Android.bp b/media/libaaudio/tests/Android.bp
index beec9e2..68194db 100644
--- a/media/libaaudio/tests/Android.bp
+++ b/media/libaaudio/tests/Android.bp
@@ -160,3 +160,10 @@
         "libutils",
     ],
 }
+
+cc_test {
+    name: "test_atomic_fifo",
+    defaults: ["libaaudio_tests_defaults"],
+    srcs: ["test_atomic_fifo.cpp"],
+    shared_libs: ["libaaudio"],
+}
diff --git a/media/libaaudio/tests/test_atomic_fifo.cpp b/media/libaaudio/tests/test_atomic_fifo.cpp
new file mode 100644
index 0000000..0085217
--- /dev/null
+++ b/media/libaaudio/tests/test_atomic_fifo.cpp
@@ -0,0 +1,229 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <iostream>
+
+#include <gtest/gtest.h>
+#include <stdlib.h>
+
+#include "fifo/FifoBuffer.h"
+#include "fifo/FifoController.h"
+
+using android::fifo_frames_t;
+using android::FifoController;
+using android::FifoBuffer;
+using android::WrappingBuffer;
+
+//void foo() {
+TEST(test_fifi_controller, fifo_indices) {
+    // Values are arbitrary primes designed to trigger edge cases.
+    constexpr int capacity = 83;
+    constexpr int threshold = 47;
+    FifoController   fifoController(capacity, threshold);
+    ASSERT_EQ(capacity, fifoController.getCapacity());
+    ASSERT_EQ(threshold, fifoController.getThreshold());
+
+    ASSERT_EQ(0, fifoController.getReadCounter());
+    ASSERT_EQ(0, fifoController.getWriteCounter());
+    ASSERT_EQ(0, fifoController.getFullFramesAvailable());
+    ASSERT_EQ(threshold, fifoController.getEmptyFramesAvailable());
+
+    // Pretend to write some data.
+    constexpr int advance1 = 23;
+    fifoController.advanceWriteIndex(advance1);
+    int advanced = advance1;
+    ASSERT_EQ(0, fifoController.getReadCounter());
+    ASSERT_EQ(0, fifoController.getReadIndex());
+    ASSERT_EQ(advanced, fifoController.getWriteCounter());
+    ASSERT_EQ(advanced, fifoController.getWriteIndex());
+    ASSERT_EQ(advanced, fifoController.getFullFramesAvailable());
+    ASSERT_EQ(threshold - advanced, fifoController.getEmptyFramesAvailable());
+
+    // Pretend to read the data.
+    fifoController.advanceReadIndex(advance1);
+    ASSERT_EQ(advanced, fifoController.getReadCounter());
+    ASSERT_EQ(advanced, fifoController.getReadIndex());
+    ASSERT_EQ(advanced, fifoController.getWriteCounter());
+    ASSERT_EQ(advanced, fifoController.getWriteIndex());
+    ASSERT_EQ(0, fifoController.getFullFramesAvailable());
+    ASSERT_EQ(threshold, fifoController.getEmptyFramesAvailable());
+
+    // Write past end of buffer.
+    constexpr int advance2 = 13 + capacity - advance1;
+    fifoController.advanceWriteIndex(advance2);
+    advanced += advance2;
+    ASSERT_EQ(advance1, fifoController.getReadCounter());
+    ASSERT_EQ(advance1, fifoController.getReadIndex());
+    ASSERT_EQ(advanced, fifoController.getWriteCounter());
+    ASSERT_EQ(advanced - capacity, fifoController.getWriteIndex());
+    ASSERT_EQ(advance2, fifoController.getFullFramesAvailable());
+    ASSERT_EQ(threshold - advance2, fifoController.getEmptyFramesAvailable());
+}
+
+// TODO consider using a template for other data types.
+class TestFifoBuffer {
+public:
+    explicit TestFifoBuffer(fifo_frames_t capacity, fifo_frames_t threshold = 0)
+        : mFifoBuffer(sizeof(int16_t), capacity) {
+        // For reading and writing.
+        mData = new int16_t[capacity];
+        if (threshold <= 0) {
+            threshold = capacity;
+        }
+        mFifoBuffer.setThreshold(threshold);
+        mThreshold = threshold;
+    }
+
+    void checkMisc() {
+        ASSERT_EQ((int32_t)(2 * sizeof(int16_t)), mFifoBuffer.convertFramesToBytes(2));
+        ASSERT_EQ(mThreshold, mFifoBuffer.getThreshold());
+    }
+
+    // Verify that the available frames in each part add up correctly.
+    void checkWrappingBuffer() {
+        WrappingBuffer wrappingBuffer;
+        fifo_frames_t framesAvailable =
+                mFifoBuffer.getFifoControllerBase()->getEmptyFramesAvailable();
+        fifo_frames_t wrapAvailable = mFifoBuffer.getEmptyRoomAvailable(&wrappingBuffer);
+        EXPECT_EQ(framesAvailable, wrapAvailable);
+        fifo_frames_t bothAvailable = wrappingBuffer.numFrames[0] + wrappingBuffer.numFrames[1];
+        EXPECT_EQ(framesAvailable, bothAvailable);
+
+        framesAvailable =
+                mFifoBuffer.getFifoControllerBase()->getFullFramesAvailable();
+        wrapAvailable = mFifoBuffer.getFullDataAvailable(&wrappingBuffer);
+        EXPECT_EQ(framesAvailable, wrapAvailable);
+        bothAvailable = wrappingBuffer.numFrames[0] + wrappingBuffer.numFrames[1];
+        EXPECT_EQ(framesAvailable, bothAvailable);
+    }
+
+    // Write data but do not overflow.
+    void writeData(fifo_frames_t numFrames) {
+        fifo_frames_t framesAvailable =
+                mFifoBuffer.getFifoControllerBase()->getEmptyFramesAvailable();
+        fifo_frames_t framesToWrite = std::min(framesAvailable, numFrames);
+        for (int i = 0; i < framesToWrite; i++) {
+            mData[i] = mNextWriteIndex++;
+        }
+        fifo_frames_t actual = mFifoBuffer.write(mData, framesToWrite);
+        ASSERT_EQ(framesToWrite, actual);
+    }
+
+    // Read data but do not underflow.
+    void verifyData(fifo_frames_t numFrames) {
+        fifo_frames_t framesAvailable =
+                mFifoBuffer.getFifoControllerBase()->getFullFramesAvailable();
+        fifo_frames_t framesToRead = std::min(framesAvailable, numFrames);
+        fifo_frames_t actual = mFifoBuffer.read(mData, framesToRead);
+        ASSERT_EQ(framesToRead, actual);
+        for (int i = 0; i < framesToRead; i++) {
+            ASSERT_EQ(mNextVerifyIndex++, mData[i]);
+        }
+    }
+
+    // Wrap around the end of the buffer.
+    void checkWrappingWriteRead() {
+        constexpr int frames1 = 43;
+        constexpr int frames2 = 15;
+
+        writeData(frames1);
+        checkWrappingBuffer();
+        verifyData(frames1);
+        checkWrappingBuffer();
+
+        writeData(frames2);
+        checkWrappingBuffer();
+        verifyData(frames2);
+        checkWrappingBuffer();
+    }
+
+    // Write and Read a specific amount of data.
+    void checkWriteRead() {
+        const fifo_frames_t capacity = mFifoBuffer.getBufferCapacityInFrames();
+        // Wrap around with the smaller region in the second half.
+        const int frames1 = capacity - 4;
+        const int frames2 = 7; // arbitrary, small
+        writeData(frames1);
+        verifyData(frames1);
+        writeData(frames2);
+        verifyData(frames2);
+    }
+
+    // Write and Read a specific amount of data.
+    void checkWriteReadSmallLarge() {
+        const fifo_frames_t capacity = mFifoBuffer.getBufferCapacityInFrames();
+        // Wrap around with the larger region in the second half.
+        const int frames1 = capacity - 4;
+        const int frames2 = capacity - 9; // arbitrary, large
+        writeData(frames1);
+        verifyData(frames1);
+        writeData(frames2);
+        verifyData(frames2);
+    }
+
+    // Randomly read or write up to the maximum amount of data.
+    void checkRandomWriteRead() {
+        for (int i = 0; i < 20; i++) {
+            fifo_frames_t framesEmpty =
+                    mFifoBuffer.getFifoControllerBase()->getEmptyFramesAvailable();
+            fifo_frames_t numFrames = (fifo_frames_t)(drand48() * framesEmpty);
+            writeData(numFrames);
+
+            fifo_frames_t framesFull =
+                    mFifoBuffer.getFifoControllerBase()->getFullFramesAvailable();
+            numFrames = (fifo_frames_t)(drand48() * framesFull);
+            verifyData(numFrames);
+        }
+    }
+
+    FifoBuffer     mFifoBuffer;
+    int16_t       *mData;
+    fifo_frames_t  mNextWriteIndex = 0;
+    fifo_frames_t  mNextVerifyIndex = 0;
+    fifo_frames_t  mThreshold;
+};
+
+TEST(test_fifo_buffer, fifo_read_write) {
+    constexpr int capacity = 51; // arbitrary
+    TestFifoBuffer tester(capacity);
+    tester.checkMisc();
+    tester.checkWriteRead();
+}
+
+TEST(test_fifo_buffer, fifo_wrapping_read_write) {
+    constexpr int capacity = 59; // arbitrary, a little bigger this time
+    TestFifoBuffer tester(capacity);
+    tester.checkWrappingWriteRead();
+}
+
+TEST(test_fifo_buffer, fifo_read_write_small_large) {
+    constexpr int capacity = 51; // arbitrary
+    TestFifoBuffer tester(capacity);
+    tester.checkWriteReadSmallLarge();
+}
+
+TEST(test_fifo_buffer, fifo_random_read_write) {
+    constexpr int capacity = 51; // arbitrary
+    TestFifoBuffer tester(capacity);
+    tester.checkRandomWriteRead();
+}
+
+TEST(test_fifo_buffer, fifo_random_threshold) {
+    constexpr int capacity = 67; // arbitrary
+    constexpr int threshold = 37; // arbitrary
+    TestFifoBuffer tester(capacity, threshold);
+    tester.checkRandomWriteRead();
+}