public unsafe void HeapAllocationShouldFree()
{
//arrange
var blocks = 256;
var size = blocks * HeapAllocation.HeapSize;
var memory = stackalloc HeapAllocation[blocks];
var span = new System.Span <HeapAllocation>(memory, blocks);
*memory = new HeapAllocation(size);
//act
HeapAllocation.Split(memory, 1);
HeapAllocation.Free(memory);
//assert
span[0].Blocks.ShouldBe((uint)blocks - 1);
span[0].SizeInBytes.ShouldBe((uint)(blocks - 1) * HeapAllocation.HeapSize);
HeapAllocation.CountFreeBlocks(memory).ShouldBe((uint)blocks - 1u);
HeapAllocation.CountUsedBlocks(memory, out var allocations).ShouldBe((uint)1u);
allocations.ShouldBe(0);
span[2].Blocks.ShouldBe(0u);
Assert(span[0].Previous == null);
Assert(span[0].Next == null);
Assert(span[2].Next == null);
Assert(span[2].Previous == null);
Assert(span[2].Flags == 0);
//Assert(span[2].Previous == null);
}
public unsafe void HeapAllocationShouldAllocate()
{
//arrange
var blocks = 256;
var size = blocks * HeapAllocation.HeapSize;
var memory = stackalloc HeapAllocation[blocks];
var span = new System.Span <HeapAllocation>(memory, blocks);
*memory = new HeapAllocation(size);
//memory->Blocks = (uint)blocks - 1; //offset the first heap block
//act
HeapAllocation.Split(memory, 1);
//assert
span[0].Flags.ShouldBe(1u);
span[0].Blocks.ShouldBe(1u);
span[0].SizeInBytes.ShouldBe(span[0].Blocks * HeapAllocation.HeapSize);
HeapAllocation.CountFreeBlocks(memory).ShouldBe((uint)blocks - 3u);
HeapAllocation.CountUsedBlocks(memory, out var allocations).ShouldBe((uint)3u);
allocations.ShouldBe(1);
span[2].Blocks.ShouldBe((uint)blocks - 3u);
Assert(span[2].Next == null);
Assert(span[0].Previous == null);
Assert(span[0].Next == &memory[2]);
Assert(span[2].Previous == &memory[0]);
}
public unsafe void HeapAllocationShouldFillGap()
{
//arrange
var blocks = 256;
var size = blocks * HeapAllocation.HeapSize;
var memory = stackalloc HeapAllocation[blocks];
var span = new System.Span <HeapAllocation>(memory, blocks);
*memory = new HeapAllocation(size);
//act
HeapAllocation.Split(memory, 1); //255
HeapAllocation.Split(&memory[2], 1); //252
HeapAllocation.Split(&memory[4], 1); //249
HeapAllocation.Free(&memory[2]);
//assert
span[0].Blocks.ShouldBe(1u);
span[2].Blocks.ShouldBe(1u);
span[4].Blocks.ShouldBe(1u);
span[6].Blocks.ShouldBe((uint)blocks - 7);
span[0].SizeInBytes.ShouldBe((uint)HeapAllocation.HeapSize);
span[2].SizeInBytes.ShouldBe((uint)HeapAllocation.HeapSize);
span[4].SizeInBytes.ShouldBe((uint)HeapAllocation.HeapSize);
span[6].SizeInBytes.ShouldBe((uint)(blocks - 7) * HeapAllocation.HeapSize);
HeapAllocation.CountFreeBlocks(memory).ShouldBe((uint)blocks - 6u);
HeapAllocation.CountUsedBlocks(memory, out var allocations).ShouldBe((uint)6u);
allocations.ShouldBe(2);
Assert(span[0].Previous == null);
Assert(span[2].Previous == &memory[0]);
Assert(span[4].Previous == &memory[2]);
Assert(span[6].Previous == &memory[4]);
Assert(span[0].Next == &memory[2]);
Assert(span[2].Next == &memory[4]);
Assert(span[4].Next == &memory[6]);
Assert(span[6].Next == null);
span[0].Flags.ShouldBe(1u);
span[2].Flags.ShouldBe(0u);
span[4].Flags.ShouldBe(1u);
span[6].Flags.ShouldBe(0u);
//act2
HeapAllocation.Free(&memory[0]);
//assert2
span[0].Blocks.ShouldBe(3u);
span[2].Blocks.ShouldBe(0u);
span[4].Blocks.ShouldBe(1u);
span[6].Blocks.ShouldBe((uint)blocks - 7);
span[0].SizeInBytes.ShouldBe((uint)HeapAllocation.HeapSize * 3);
span[2].SizeInBytes.ShouldBe(0u);
span[4].SizeInBytes.ShouldBe((uint)HeapAllocation.HeapSize);
span[6].SizeInBytes.ShouldBe((uint)(blocks - 7) * HeapAllocation.HeapSize);
HeapAllocation.CountFreeBlocks(memory).ShouldBe((uint)blocks - 4u);
HeapAllocation.CountUsedBlocks(memory, out allocations).ShouldBe((uint)4u);
allocations.ShouldBe(1);
Assert(span[0].Previous == null);
Assert(span[2].Previous == null);
Assert(span[4].Previous == &memory[0]);
Assert(span[6].Previous == &memory[4]);
Assert(span[0].Next == &memory[4]);
Assert(span[2].Next == null);
Assert(span[4].Next == &memory[6]);
Assert(span[6].Next == null);
span[0].Flags.ShouldBe(0u);
span[2].Flags.ShouldBe(0u);
span[4].Flags.ShouldBe(1u);
span[6].Flags.ShouldBe(0u);
//act3
HeapAllocation.Free(&memory[4]);
//assert3
span[0].Blocks.ShouldBe((uint)(blocks - 1));
span[2].Blocks.ShouldBe(0u);
span[4].Blocks.ShouldBe(0u);
span[6].Blocks.ShouldBe(0u);
span[0].SizeInBytes.ShouldBe((uint)(HeapAllocation.HeapSize * (blocks - 1)));
span[2].SizeInBytes.ShouldBe(0u);
span[4].SizeInBytes.ShouldBe(0u);
span[6].SizeInBytes.ShouldBe(0u);
HeapAllocation.CountFreeBlocks(memory).ShouldBe((uint)(blocks - 1u));
HeapAllocation.CountUsedBlocks(memory, out allocations).ShouldBe(1u);
allocations.ShouldBe(0);
Assert(span[0].Previous == null);
Assert(span[2].Previous == null);
Assert(span[4].Previous == null);
Assert(span[6].Previous == null);
Assert(span[0].Next == null);
Assert(span[2].Next == null);
Assert(span[4].Next == null);
Assert(span[6].Next == null);
span[0].Flags.ShouldBe(0u);
span[2].Flags.ShouldBe(0u);
span[4].Flags.ShouldBe(0u);
span[6].Flags.ShouldBe(0u);
}