Move aligned memory utilities to rtc_base/memory/

This moves them from an API directory (system_wrappers/include/) to a
non-API directory, which is exactly what we want for utilities like
this.

BUG=webrtc:8445

Change-Id: I6dc34fe662f5d87b3b5288d33055345bc6bf91db
Reviewed-on: https://webrtc-review.googlesource.com/21164
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22567}

rtc_base/BUILD.gn

@@ -1228,6 +1228,7 @@ if (rtc_include_tests) {
       "../system_wrappers:system_wrappers",
       "../test:fileutils",
       "../test:test_support",
+      "memory:unittests",
     ]
   }
 

rtc_base/memory/BUILD.gn

@@ -0,0 +1,47 @@
+# Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+import("../../webrtc.gni")
+if (is_android) {
+  import("//build/config/android/config.gni")
+  import("//build/config/android/rules.gni")
+}
+
+rtc_source_set("aligned_array") {
+  sources = [
+    "aligned_array.h",
+  ]
+  deps = [
+    ":aligned_malloc",
+    "..:checks",
+  ]
+}
+
+rtc_source_set("aligned_malloc") {
+  sources = [
+    "aligned_malloc.cc",
+    "aligned_malloc.h",
+  ]
+  deps = [
+    "../..:typedefs",
+  ]
+}
+
+rtc_source_set("unittests") {
+  testonly = true
+  sources = [
+    "aligned_array_unittest.cc",
+    "aligned_malloc_unittest.cc",
+  ]
+  deps = [
+    ":aligned_array",
+    ":aligned_malloc",
+    "../..:typedefs",
+    "../../test:test_support",
+  ]
+}

rtc_base/memory/aligned_array.h

@@ -0,0 +1,78 @@
+/*
+ *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef RTC_BASE_MEMORY_ALIGNED_ARRAY_H_
+#define RTC_BASE_MEMORY_ALIGNED_ARRAY_H_
+
+#include "rtc_base/checks.h"
+#include "rtc_base/memory/aligned_malloc.h"
+
+namespace webrtc {
+
+// Wrapper class for aligned arrays. Every row (and the first dimension) are
+// aligned to the given byte alignment.
+template <typename T>
+class AlignedArray {
+ public:
+  AlignedArray(size_t rows, size_t cols, size_t alignment)
+      : rows_(rows), cols_(cols) {
+    RTC_CHECK_GT(alignment, 0);
+    head_row_ =
+        static_cast<T**>(AlignedMalloc(rows_ * sizeof(*head_row_), alignment));
+    for (size_t i = 0; i < rows_; ++i) {
+      head_row_[i] = static_cast<T*>(
+          AlignedMalloc(cols_ * sizeof(**head_row_), alignment));
+    }
+  }
+
+  ~AlignedArray() {
+    for (size_t i = 0; i < rows_; ++i) {
+      AlignedFree(head_row_[i]);
+    }
+    AlignedFree(head_row_);
+  }
+
+  T* const* Array() { return head_row_; }
+
+  const T* const* Array() const { return head_row_; }
+
+  T* Row(size_t row) {
+    RTC_CHECK_LE(row, rows_);
+    return head_row_[row];
+  }
+
+  const T* Row(size_t row) const {
+    RTC_CHECK_LE(row, rows_);
+    return head_row_[row];
+  }
+
+  T& At(size_t row, size_t col) {
+    RTC_CHECK_LE(col, cols_);
+    return Row(row)[col];
+  }
+
+  const T& At(size_t row, size_t col) const {
+    RTC_CHECK_LE(col, cols_);
+    return Row(row)[col];
+  }
+
+  size_t rows() const { return rows_; }
+
+  size_t cols() const { return cols_; }
+
+ private:
+  size_t rows_;
+  size_t cols_;
+  T** head_row_;
+};
+
+}  // namespace webrtc
+
+#endif  // RTC_BASE_MEMORY_ALIGNED_ARRAY_H_

rtc_base/memory/aligned_array_unittest.cc

@@ -0,0 +1,60 @@
+/*
+ *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "rtc_base/memory/aligned_array.h"
+
+#include <stdint.h>
+
+#include "test/gtest.h"
+
+namespace {
+
+bool IsAligned(const void* ptr, size_t alignment) {
+  return reinterpret_cast<uintptr_t>(ptr) % alignment == 0;
+}
+
+}  // namespace
+
+namespace webrtc {
+
+TEST(AlignedArrayTest, CheckAlignment) {
+  AlignedArray<bool> arr(10, 7, 128);
+  ASSERT_TRUE(IsAligned(arr.Array(), 128));
+  for (size_t i = 0; i < 10; ++i) {
+    ASSERT_TRUE(IsAligned(arr.Row(i), 128));
+    ASSERT_EQ(arr.Row(i), arr.Array()[i]);
+  }
+}
+
+TEST(AlignedArrayTest, CheckOverlap) {
+  AlignedArray<size_t> arr(10, 7, 128);
+
+  for (size_t i = 0; i < 10; ++i) {
+    for (size_t j = 0; j < 7; ++j) {
+      arr.At(i, j) = 20 * i + j;
+    }
+  }
+
+  for (size_t i = 0; i < 10; ++i) {
+    for (size_t j = 0; j < 7; ++j) {
+      ASSERT_EQ(arr.At(i, j), 20 * i + j);
+      ASSERT_EQ(arr.Row(i)[j], 20 * i + j);
+      ASSERT_EQ(arr.Array()[i][j], 20 * i + j);
+    }
+  }
+}
+
+TEST(AlignedArrayTest, CheckRowsCols) {
+  AlignedArray<bool> arr(10, 7, 128);
+  ASSERT_EQ(arr.rows(), 10u);
+  ASSERT_EQ(arr.cols(), 7u);
+}
+
+}  // namespace webrtc

rtc_base/memory/aligned_malloc.cc

@@ -0,0 +1,100 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "rtc_base/memory/aligned_malloc.h"
+
+#include <memory.h>
+#include <stdlib.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <stdint.h>
+#endif
+
+#include "typedefs.h"  // NOLINT(build/include)
+
+// Reference on memory alignment:
+// http://stackoverflow.com/questions/227897/solve-the-memory-alignment-in-c-interview-question-that-stumped-me
+namespace webrtc {
+
+uintptr_t GetRightAlign(uintptr_t start_pos, size_t alignment) {
+  // The pointer should be aligned with |alignment| bytes. The - 1 guarantees
+  // that it is aligned towards the closest higher (right) address.
+  return (start_pos + alignment - 1) & ~(alignment - 1);
+}
+
+// Alignment must be an integer power of two.
+bool ValidAlignment(size_t alignment) {
+  if (!alignment) {
+    return false;
+  }
+  return (alignment & (alignment - 1)) == 0;
+}
+
+void* GetRightAlign(const void* pointer, size_t alignment) {
+  if (!pointer) {
+    return NULL;
+  }
+  if (!ValidAlignment(alignment)) {
+    return NULL;
+  }
+  uintptr_t start_pos = reinterpret_cast<uintptr_t>(pointer);
+  return reinterpret_cast<void*>(GetRightAlign(start_pos, alignment));
+}
+
+void* AlignedMalloc(size_t size, size_t alignment) {
+  if (size == 0) {
+    return NULL;
+  }
+  if (!ValidAlignment(alignment)) {
+    return NULL;
+  }
+
+  // The memory is aligned towards the lowest address that so only
+  // alignment - 1 bytes needs to be allocated.
+  // A pointer to the start of the memory must be stored so that it can be
+  // retreived for deletion, ergo the sizeof(uintptr_t).
+  void* memory_pointer = malloc(size + sizeof(uintptr_t) + alignment - 1);
+  if (memory_pointer == NULL) {
+    return NULL;
+  }
+
+  // Aligning after the sizeof(uintptr_t) bytes will leave room for the header
+  // in the same memory block.
+  uintptr_t align_start_pos = reinterpret_cast<uintptr_t>(memory_pointer);
+  align_start_pos += sizeof(uintptr_t);
+  uintptr_t aligned_pos = GetRightAlign(align_start_pos, alignment);
+  void* aligned_pointer = reinterpret_cast<void*>(aligned_pos);
+
+  // Store the address to the beginning of the memory just before the aligned
+  // memory.
+  uintptr_t header_pos = aligned_pos - sizeof(uintptr_t);
+  void* header_pointer = reinterpret_cast<void*>(header_pos);
+  uintptr_t memory_start = reinterpret_cast<uintptr_t>(memory_pointer);
+  memcpy(header_pointer, &memory_start, sizeof(uintptr_t));
+
+  return aligned_pointer;
+}
+
+void AlignedFree(void* mem_block) {
+  if (mem_block == NULL) {
+    return;
+  }
+  uintptr_t aligned_pos = reinterpret_cast<uintptr_t>(mem_block);
+  uintptr_t header_pos = aligned_pos - sizeof(uintptr_t);
+
+  // Read out the address of the AlignedMemory struct from the header.
+  uintptr_t memory_start_pos = *reinterpret_cast<uintptr_t*>(header_pos);
+  void* memory_start = reinterpret_cast<void*>(memory_start_pos);
+  free(memory_start);
+}
+
+}  // namespace webrtc

rtc_base/memory/aligned_malloc.h

@@ -0,0 +1,57 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef RTC_BASE_MEMORY_ALIGNED_MALLOC_H_
+#define RTC_BASE_MEMORY_ALIGNED_MALLOC_H_
+
+// The functions declared here
+// 1) Allocates block of aligned memory.
+// 2) Re-calculates a pointer such that it is aligned to a higher or equal
+//    address.
+// Note: alignment must be a power of two. The alignment is in bytes.
+
+#include <stddef.h>
+
+namespace webrtc {
+
+// Returns a pointer to the first boundry of |alignment| bytes following the
+// address of |ptr|.
+// Note that there is no guarantee that the memory in question is available.
+// |ptr| has no requirements other than it can't be NULL.
+void* GetRightAlign(const void* ptr, size_t alignment);
+
+// Allocates memory of |size| bytes aligned on an |alignment| boundry.
+// The return value is a pointer to the memory. Note that the memory must
+// be de-allocated using AlignedFree.
+void* AlignedMalloc(size_t size, size_t alignment);
+// De-allocates memory created using the AlignedMalloc() API.
+void AlignedFree(void* mem_block);
+
+// Templated versions to facilitate usage of aligned malloc without casting
+// to and from void*.
+template <typename T>
+T* GetRightAlign(const T* ptr, size_t alignment) {
+  return reinterpret_cast<T*>(
+      GetRightAlign(reinterpret_cast<const void*>(ptr), alignment));
+}
+template <typename T>
+T* AlignedMalloc(size_t size, size_t alignment) {
+  return reinterpret_cast<T*>(AlignedMalloc(size, alignment));
+}
+
+// Deleter for use with unique_ptr. E.g., use as
+//   std::unique_ptr<Foo, AlignedFreeDeleter> foo;
+struct AlignedFreeDeleter {
+  inline void operator()(void* ptr) const { AlignedFree(ptr); }
+};
+
+}  // namespace webrtc
+
+#endif  // RTC_BASE_MEMORY_ALIGNED_MALLOC_H_

rtc_base/memory/aligned_malloc_unittest.cc

@@ -0,0 +1,82 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "rtc_base/memory/aligned_malloc.h"
+
+#include <memory>
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <stdint.h>
+#endif
+
+#include "test/gtest.h"
+#include "typedefs.h"  // NOLINT(build/include)
+
+namespace webrtc {
+
+// Returns true if |size| and |alignment| are valid combinations.
+bool CorrectUsage(size_t size, size_t alignment) {
+  std::unique_ptr<char, AlignedFreeDeleter> scoped(
+      static_cast<char*>(AlignedMalloc(size, alignment)));
+  if (scoped.get() == NULL) {
+    return false;
+  }
+  const uintptr_t scoped_address = reinterpret_cast<uintptr_t>(scoped.get());
+  return 0u == scoped_address % alignment;
+}
+
+TEST(AlignedMalloc, GetRightAlign) {
+  const size_t size = 100;
+  const size_t alignment = 32;
+  const size_t left_misalignment = 1;
+  std::unique_ptr<char, AlignedFreeDeleter> scoped(
+      static_cast<char*>(AlignedMalloc(size, alignment)));
+  EXPECT_TRUE(scoped.get() != NULL);
+  const uintptr_t aligned_address = reinterpret_cast<uintptr_t>(scoped.get());
+  const uintptr_t misaligned_address = aligned_address - left_misalignment;
+  const char* misaligned_ptr =
+      reinterpret_cast<const char*>(misaligned_address);
+  const char* realigned_ptr = GetRightAlign(misaligned_ptr, alignment);
+  EXPECT_EQ(scoped.get(), realigned_ptr);
+}
+
+TEST(AlignedMalloc, IncorrectSize) {
+  const size_t incorrect_size = 0;
+  const size_t alignment = 64;
+  EXPECT_FALSE(CorrectUsage(incorrect_size, alignment));
+}
+
+TEST(AlignedMalloc, IncorrectAlignment) {
+  const size_t size = 100;
+  const size_t incorrect_alignment = 63;
+  EXPECT_FALSE(CorrectUsage(size, incorrect_alignment));
+}
+
+TEST(AlignedMalloc, AlignTo2Bytes) {
+  size_t size = 100;
+  size_t alignment = 2;
+  EXPECT_TRUE(CorrectUsage(size, alignment));
+}
+
+TEST(AlignedMalloc, AlignTo32Bytes) {
+  size_t size = 100;
+  size_t alignment = 32;
+  EXPECT_TRUE(CorrectUsage(size, alignment));
+}
+
+TEST(AlignedMalloc, AlignTo128Bytes) {
+  size_t size = 100;
+  size_t alignment = 128;
+  EXPECT_TRUE(CorrectUsage(size, alignment));
+}
+
+}  // namespace webrtc