[wpiutil] Add circular buffer class with static size (#2542)

This complements wpi::circular_buffer which supports dynamic resizing.
2026-06-20 00:51:42 +00:00 · 2020-06-29 21:51:05 -07:00
parent e50dbe0c43
commit e08c8a1fc9
2 changed files with 427 additions and 0 deletions
--- a/wpiutil/src/test/native/cpp/StaticCircularBufferTest.cpp
+++ b/wpiutil/src/test/native/cpp/StaticCircularBufferTest.cpp
@@ -0,0 +1,151 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2020 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "wpi/static_circular_buffer.h"  // NOLINT(build/include_order)
+
+#include <array>
+
+#include "gtest/gtest.h"
+
+static const std::array<double, 10> values = {
+    {751.848, 766.366, 342.657, 234.252, 716.126, 132.344, 445.697, 22.727,
+     421.125, 799.913}};
+
+static const std::array<double, 8> pushFrontOut = {
+    {799.913, 421.125, 22.727, 445.697, 132.344, 716.126, 234.252, 342.657}};
+
+static const std::array<double, 8> pushBackOut = {
+    {342.657, 234.252, 716.126, 132.344, 445.697, 22.727, 421.125, 799.913}};
+
+TEST(StaticCircularBufferTest, PushFrontTest) {
+  wpi::static_circular_buffer<double, 8> queue;
+
+  for (auto& value : values) {
+    queue.push_front(value);
+  }
+
+  for (size_t i = 0; i < pushFrontOut.size(); ++i) {
+    EXPECT_EQ(pushFrontOut[i], queue[i]);
+  }
+}
+
+TEST(StaticCircularBufferTest, PushBackTest) {
+  wpi::static_circular_buffer<double, 8> queue;
+
+  for (auto& value : values) {
+    queue.push_back(value);
+  }
+
+  for (size_t i = 0; i < pushBackOut.size(); ++i) {
+    EXPECT_EQ(pushBackOut[i], queue[i]);
+  }
+}
+
+TEST(StaticCircularBufferTest, EmplaceFrontTest) {
+  wpi::static_circular_buffer<double, 8> queue;
+
+  for (auto& value : values) {
+    queue.emplace_front(value);
+  }
+
+  for (size_t i = 0; i < pushFrontOut.size(); ++i) {
+    EXPECT_EQ(pushFrontOut[i], queue[i]);
+  }
+}
+
+TEST(StaticCircularBufferTest, EmplaceBackTest) {
+  wpi::static_circular_buffer<double, 8> queue;
+
+  for (auto& value : values) {
+    queue.emplace_back(value);
+  }
+
+  for (size_t i = 0; i < pushBackOut.size(); ++i) {
+    EXPECT_EQ(pushBackOut[i], queue[i]);
+  }
+}
+
+TEST(StaticCircularBufferTest, PushPopTest) {
+  wpi::static_circular_buffer<double, 3> queue;
+
+  // Insert three elements into the buffer
+  queue.push_back(1.0);
+  queue.push_back(2.0);
+  queue.push_back(3.0);
+
+  EXPECT_EQ(1.0, queue[0]);
+  EXPECT_EQ(2.0, queue[1]);
+  EXPECT_EQ(3.0, queue[2]);
+
+  /*
+   * The buffer is full now, so pushing subsequent elements will overwrite the
+   * front-most elements.
+   */
+
+  queue.push_back(4.0);  // Overwrite 1 with 4
+
+  // The buffer now contains 2, 3 and 4
+  EXPECT_EQ(2.0, queue[0]);
+  EXPECT_EQ(3.0, queue[1]);
+  EXPECT_EQ(4.0, queue[2]);
+
+  queue.push_back(5.0);  // Overwrite 2 with 5
+
+  // The buffer now contains 3, 4 and 5
+  EXPECT_EQ(3.0, queue[0]);
+  EXPECT_EQ(4.0, queue[1]);
+  EXPECT_EQ(5.0, queue[2]);
+
+  EXPECT_EQ(5.0, queue.pop_back());  // 5 is removed
+
+  // The buffer now contains 3 and 4
+  EXPECT_EQ(3.0, queue[0]);
+  EXPECT_EQ(4.0, queue[1]);
+
+  EXPECT_EQ(3.0, queue.pop_front());  // 3 is removed
+
+  // Leaving only one element with value == 4
+  EXPECT_EQ(4.0, queue[0]);
+}
+
+TEST(StaticCircularBufferTest, ResetTest) {
+  wpi::static_circular_buffer<double, 5> queue;
+
+  for (size_t i = 1; i < 6; ++i) {
+    queue.push_back(i);
+  }
+
+  queue.reset();
+
+  EXPECT_EQ(queue.size(), size_t{0});
+}
+
+TEST(StaticCircularBufferTest, IteratorTest) {
+  wpi::static_circular_buffer<double, 3> queue;
+
+  queue.push_back(1.0);
+  queue.push_back(2.0);
+  queue.push_back(3.0);
+  queue.push_back(4.0);  // Overwrite 1 with 4
+
+  // The buffer now contains 2, 3 and 4
+  const std::array<double, 3> values = {2.0, 3.0, 4.0};
+
+  // iterator
+  int i = 0;
+  for (auto& elem : queue) {
+    EXPECT_EQ(values[i], elem);
+    ++i;
+  }
+
+  // const_iterator
+  i = 0;
+  for (const auto& elem : queue) {
+    EXPECT_EQ(values[i], elem);
+    ++i;
+  }
+}