1 files changed, 116 insertions, 0 deletions
diff --git a/pw_bytes/alignment_test.cc b/pw_bytes/alignment_test.cc
new file mode 100644
index 000000000..9a6e2616a
--- /dev/null
+++ b/pw_bytes/alignment_test.cc
@@ -0,0 +1,116 @@
+// Copyright 2023 The Pigweed Authors
+//
+// 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
+//
+//     https://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 "pw_bytes/alignment.h"
+
+#include "gtest/gtest.h"
+
+namespace pw {
+namespace {
+
+TEST(AlignUp, Zero) {
+  EXPECT_EQ(0u, AlignUp(0, 1));
+  EXPECT_EQ(0u, AlignUp(0, 2));
+  EXPECT_EQ(0u, AlignUp(0, 15));
+}
+
+TEST(AlignUp, Aligned) {
+  for (size_t i = 1; i < 130; ++i) {
+    EXPECT_EQ(i, AlignUp(i, i));
+    EXPECT_EQ(2 * i, AlignUp(2 * i, i));
+    EXPECT_EQ(3 * i, AlignUp(3 * i, i));
+  }
+}
+
+TEST(AlignUp, NonAligned_PowerOf2) {
+  EXPECT_EQ(32u, AlignUp(1, 32));
+  EXPECT_EQ(32u, AlignUp(31, 32));
+  EXPECT_EQ(64u, AlignUp(33, 32));
+  EXPECT_EQ(64u, AlignUp(45, 32));
+  EXPECT_EQ(64u, AlignUp(63, 32));
+  EXPECT_EQ(128u, AlignUp(127, 32));
+}
+
+TEST(AlignUp, NonAligned_NonPowerOf2) {
+  EXPECT_EQ(2u, AlignUp(1, 2));
+
+  EXPECT_EQ(15u, AlignUp(1, 15));
+  EXPECT_EQ(15u, AlignUp(14, 15));
+  EXPECT_EQ(30u, AlignUp(16, 15));
+}
+
+TEST(AlignDown, Zero) {
+  EXPECT_EQ(0u, AlignDown(0, 1));
+  EXPECT_EQ(0u, AlignDown(0, 2));
+  EXPECT_EQ(0u, AlignDown(0, 15));
+}
+
+TEST(AlignDown, Aligned) {
+  for (size_t i = 1; i < 130; ++i) {
+    EXPECT_EQ(i, AlignDown(i, i));
+    EXPECT_EQ(2 * i, AlignDown(2 * i, i));
+    EXPECT_EQ(3 * i, AlignDown(3 * i, i));
+  }
+}
+
+TEST(AlignDown, NonAligned_PowerOf2) {
+  EXPECT_EQ(0u, AlignDown(1, 32));
+  EXPECT_EQ(0u, AlignDown(31, 32));
+  EXPECT_EQ(32u, AlignDown(33, 32));
+  EXPECT_EQ(32u, AlignDown(45, 32));
+  EXPECT_EQ(32u, AlignDown(63, 32));
+  EXPECT_EQ(96u, AlignDown(127, 32));
+}
+
+TEST(AlignDown, NonAligned_NonPowerOf2) {
+  EXPECT_EQ(0u, AlignDown(1, 2));
+
+  EXPECT_EQ(0u, AlignDown(1, 15));
+  EXPECT_EQ(0u, AlignDown(14, 15));
+  EXPECT_EQ(15u, AlignDown(16, 15));
+}
+
+TEST(Padding, Zero) {
+  EXPECT_EQ(0u, Padding(0, 1));
+  EXPECT_EQ(0u, Padding(0, 2));
+  EXPECT_EQ(0u, Padding(0, 15));
+}
+
+TEST(Padding, Aligned) {
+  for (size_t i = 1; i < 130; ++i) {
+    EXPECT_EQ(0u, Padding(i, i));
+    EXPECT_EQ(0u, Padding(2 * i, i));
+    EXPECT_EQ(0u, Padding(3 * i, i));
+  }
+}
+
+TEST(Padding, NonAligned_PowerOf2) {
+  EXPECT_EQ(31u, Padding(1, 32));
+  EXPECT_EQ(1u, Padding(31, 32));
+  EXPECT_EQ(31u, Padding(33, 32));
+  EXPECT_EQ(19u, Padding(45, 32));
+  EXPECT_EQ(1u, Padding(63, 32));
+  EXPECT_EQ(1u, Padding(127, 32));
+}
+
+TEST(Padding, NonAligned_NonPowerOf2) {
+  EXPECT_EQ(1u, Padding(1, 2));
+
+  EXPECT_EQ(14u, Padding(1, 15));
+  EXPECT_EQ(1u, Padding(14, 15));
+  EXPECT_EQ(14u, Padding(16, 15));
+}
+
+}  // namespace
+}  // namespace pw