From c5f4d5e448e4508586087e7ec8edfb0a2b6c38ec Mon Sep 17 00:00:00 2001
From: Jacques Lucke <jacques@blender.org>
Date: Fri, 24 Apr 2020 23:52:55 +0200
Subject: BLI: add LinearAllocator

This allocator is useful when it is necessary to allocate many small elements.
---
 tests/gtests/blenlib/BLI_linear_allocator_test.cc | 113 ++++++++++++++++++++++
 tests/gtests/blenlib/CMakeLists.txt               |   1 +
 2 files changed, 114 insertions(+)
 create mode 100644 tests/gtests/blenlib/BLI_linear_allocator_test.cc

(limited to 'tests/gtests')

diff --git a/tests/gtests/blenlib/BLI_linear_allocator_test.cc b/tests/gtests/blenlib/BLI_linear_allocator_test.cc
new file mode 100644
index 00000000000..0c67d1e76c9
--- /dev/null
+++ b/tests/gtests/blenlib/BLI_linear_allocator_test.cc
@@ -0,0 +1,113 @@
+#include "BLI_linear_allocator.hh"
+#include "testing/testing.h"
+
+using namespace BLI;
+
+static bool is_aligned(void *ptr, uint alignment)
+{
+  BLI_assert(is_power_of_2_i(alignment));
+  return (POINTER_AS_UINT(ptr) & (alignment - 1)) == 0;
+}
+
+TEST(linear_allocator, AllocationAlignment)
+{
+  LinearAllocator<> allocator;
+
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 4), 4));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 4), 4));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 4), 4));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 8), 8));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 4), 4));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 16), 16));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 4), 4));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 64), 64));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 64), 64));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 8), 8));
+  EXPECT_TRUE(is_aligned(allocator.allocate(10, 128), 128));
+}
+
+TEST(linear_allocator, PackedAllocation)
+{
+  LinearAllocator<> allocator;
+  BLI::AlignedBuffer<256, 32> buffer;
+  allocator.provide_buffer(buffer);
+
+  uintptr_t ptr1 = (uintptr_t)allocator.allocate(10, 4); /*  0 - 10 */
+  uintptr_t ptr2 = (uintptr_t)allocator.allocate(10, 4); /* 12 - 22 */
+  uintptr_t ptr3 = (uintptr_t)allocator.allocate(8, 32); /* 32 - 40 */
+  uintptr_t ptr4 = (uintptr_t)allocator.allocate(16, 8); /* 40 - 56 */
+  uintptr_t ptr5 = (uintptr_t)allocator.allocate(1, 8);  /* 56 - 57 */
+  uintptr_t ptr6 = (uintptr_t)allocator.allocate(1, 4);  /* 60 - 61 */
+  uintptr_t ptr7 = (uintptr_t)allocator.allocate(1, 1);  /* 61 - 62 */
+
+  EXPECT_EQ(ptr2 - ptr1, 12); /* 12 -  0 = 12 */
+  EXPECT_EQ(ptr3 - ptr2, 20); /* 32 - 12 = 20 */
+  EXPECT_EQ(ptr4 - ptr3, 8);  /* 40 - 32 =  8 */
+  EXPECT_EQ(ptr5 - ptr4, 16); /* 56 - 40 = 16 */
+  EXPECT_EQ(ptr6 - ptr5, 4);  /* 60 - 56 =  4 */
+  EXPECT_EQ(ptr7 - ptr6, 1);  /* 61 - 60 =  1 */
+}
+
+TEST(linear_allocator, CopyString)
+{
+  LinearAllocator<> allocator;
+  BLI::AlignedBuffer<256, 1> buffer;
+  allocator.provide_buffer(buffer);
+
+  StringRefNull ref1 = allocator.copy_string("Hello");
+  StringRefNull ref2 = allocator.copy_string("World");
+
+  EXPECT_EQ(ref1, "Hello");
+  EXPECT_EQ(ref2, "World");
+  EXPECT_EQ(ref2.data() - ref1.data(), 6);
+}
+
+TEST(linear_allocator, AllocateArray)
+{
+  LinearAllocator<> allocator;
+
+  MutableArrayRef<int> array = allocator.allocate_array<int>(5);
+  EXPECT_EQ(array.size(), 5);
+}
+
+TEST(linear_allocator, Construct)
+{
+  LinearAllocator<> allocator;
+
+  std::array<int, 5> values = {1, 2, 3, 4, 5};
+  Vector<int> *vector = allocator.construct<Vector<int>>(values);
+  EXPECT_EQ(vector->size(), 5);
+  EXPECT_EQ((*vector)[3], 4);
+  vector->~Vector();
+}
+
+TEST(linear_allocator, ConstructElementsAndPointerArray)
+{
+  LinearAllocator<> allocator;
+
+  std::array<int, 7> values = {1, 2, 3, 4, 5, 6, 7};
+  ArrayRef<Vector<int> *> vectors = allocator.construct_elements_and_pointer_array<Vector<int>>(
+      5, values);
+
+  EXPECT_EQ(vectors.size(), 5);
+  EXPECT_EQ(vectors[3]->size(), 7);
+  EXPECT_EQ((*vectors[2])[5], 6);
+
+  for (Vector<int> *vector : vectors) {
+    vector->~Vector();
+  }
+}
+
+TEST(linear_allocator, ConstructArrayCopy)
+{
+  LinearAllocator<> allocator;
+
+  Vector<int> values = {1, 2, 3};
+  MutableArrayRef<int> array1 = allocator.construct_array_copy(values.as_ref());
+  MutableArrayRef<int> array2 = allocator.construct_array_copy(values.as_ref());
+  EXPECT_NE(array1.begin(), array2.begin());
+  EXPECT_EQ(array1.size(), 3);
+  EXPECT_EQ(array2.size(), 3);
+  EXPECT_EQ(array1[1], 2);
+  EXPECT_EQ(array2[2], 3);
+}
diff --git a/tests/gtests/blenlib/CMakeLists.txt b/tests/gtests/blenlib/CMakeLists.txt
index 119b54fa0d4..a0621448630 100644
--- a/tests/gtests/blenlib/CMakeLists.txt
+++ b/tests/gtests/blenlib/CMakeLists.txt
@@ -52,6 +52,7 @@ BLENDER_TEST(BLI_heap "bf_blenlib")
 BLENDER_TEST(BLI_heap_simple "bf_blenlib")
 BLENDER_TEST(BLI_index_range "bf_blenlib")
 BLENDER_TEST(BLI_kdopbvh "bf_blenlib;bf_intern_numaapi")
+BLENDER_TEST(BLI_linear_allocator "bf_blenlib")
 BLENDER_TEST(BLI_linklist_lockfree "bf_blenlib;bf_intern_numaapi")
 BLENDER_TEST(BLI_listbase "bf_blenlib")
 BLENDER_TEST(BLI_map "bf_blenlib")
-- 
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