/// <summary>
/// Allocates an index which corresponds to a buffer.
/// </summary>
/// <returns>Allocated index. If allocation fails, returned index is negative.</returns>
/// <exception cref="InvalidOperationException">Thrown when allocator is exhausted or when buffer cannot be committed.</exception>
public int Allocate()
{
if (FreeList.IsEmpty)
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
throw new InvalidOperationException("Cannot allocate, allocator is exhausted.");
#else
return(-1);
#endif
}
int lastFreeListIndex = FreeList.Length - 1;
int index = FreeList.Ptr[lastFreeListIndex];
BaselibErrorState errorState;
var range = new VMRange((IntPtr)this[index], (uint)BufferSizeInBytes, VirtualMemoryUtility.DefaultPageSizeInBytes);
VirtualMemoryUtility.CommitMemory(range, out errorState);
if (!errorState.Success)
{
#if ENABLE_UNITY_COLLECTIONS_CHECKS
throw new InvalidOperationException($"Failed to commit address range {range}.");
#else
return(-1);
#endif
}
FreeList.RemoveAtSwapBack(lastFreeListIndex);
return(index);
}
public unsafe void VirtualMemory_Allocate()
{
BaselibErrorState errorState = default;
// Reserve 4GB
var addressSpace = VirtualMemoryUtility.ReserveAddressSpace(1024ul * 1024ul, VirtualMemoryUtility.DefaultPageSizeInBytes, out errorState);
{
// Commit 1 page for an allocator
VMRange page = new VMRange {
ptr = addressSpace.ptr, log2PageSize = addressSpace.log2PageSize, pageCount = 1
};
VirtualMemoryUtility.CommitMemory(page, out errorState);
// 1KB allocator
var allocator = new UnsafeScratchAllocator((void *)page.ptr, 1024);
var numbers0 = (int *)allocator.Allocate <int>(256);
for (int i = 0; i < 256; i++)
{
numbers0[i] = i;
}
var anotherAllocator = new UnsafeScratchAllocator((void *)((IntPtr)page.ptr + 1024), 1024);
var numbers1 = (int *)anotherAllocator.Allocate <int>(256);
for (int i = 0; i < 256; i++)
{
numbers1[i] = numbers0[i];
}
}
VirtualMemoryUtility.FreeAddressSpace(addressSpace, out errorState);
}
public unsafe void VirtualMemory_Decommit()
{
BaselibErrorState errorState = default;
// Reserve 4GB
var addressSpace = VirtualMemoryUtility.ReserveAddressSpace(1024ul * 1024ul, VirtualMemoryUtility.DefaultPageSizeInBytes, out errorState);
{
// Commit 4KB for an allocator
VMRange page = new VMRange {
ptr = addressSpace.ptr, log2PageSize = addressSpace.log2PageSize, pageCount = 1
};
VirtualMemoryUtility.CommitMemory(page, out errorState);
var allocator = new UnsafeScratchAllocator((void *)page.ptr, 4096);
var numbers0 = (int *)allocator.Allocate <int>(256);
for (int i = 0; i < 256; i++)
{
numbers0[i] = i;
}
// Decommit and try to use
VirtualMemoryUtility.DecommitMemory(page, out errorState);
Assert.Throws <NullReferenceException>(() => numbers0[1] = 1);
}
VirtualMemoryUtility.FreeAddressSpace(addressSpace, out errorState);
}
public void Execute(int index)
{
BaselibErrorState errorState = default;
VMRange allocation = new VMRange {
ptr = jobAddressRangePtr + index * (int)VirtualMemoryUtility.DefaultPageSizeInBytes, log2PageSize = jobLog2PageSize, pageCount = jobPageCount
};
// Commit a page from the address range
VirtualMemoryUtility.CommitMemory(allocation, out errorState);
jobErrorStates[index] = errorState;
// 1 page of ints
var allocator = new UnsafeScratchAllocator((void *)allocation.ptr, (int)VirtualMemoryUtility.DefaultPageSizeInBytes);
var numbers0 = (int *)allocator.Allocate <int>((int)VirtualMemoryUtility.DefaultPageSizeInBytes / sizeof(int));
for (int i = 0; i < (int)VirtualMemoryUtility.DefaultPageSizeInBytes / sizeof(int); i++)
{
numbers0[i] = i;
}
}
public unsafe void VirtualMemory_OvercommitReservedMemory()
{
BaselibErrorState errorState = default;
// Reserve 1 page
var addressSpace = VirtualMemoryUtility.ReserveAddressSpace(1, VirtualMemoryUtility.DefaultPageSizeInBytes, out errorState);
{
// Try to commit 2 pages (will fail).
VMRange pages = new VMRange {
ptr = addressSpace.ptr, log2PageSize = addressSpace.log2PageSize, pageCount = 2
};
VirtualMemoryUtility.CommitMemory(pages, out errorState);
VirtualMemoryUtility.ReportWrappedBaselibError(errorState);
LogAssert.Expect(LogType.Error, new Regex("Baselib error:*"));
var coolByte = (byte *)pages.ptr;
// Try to write to uncommitted memory (will fail and throw an exception).
Assert.Throws <NullReferenceException>(() => *coolByte = 0);
}
VirtualMemoryUtility.FreeAddressSpace(addressSpace, out errorState);
}
