using System;
using System.Runtime.InteropServices;
using Vanara.InteropServices;

namespace Vanara.PInvoke
{
	public static partial class Kernel32
	{
		/// <summary>Specifies the class of heap information to be set or retrieved.</summary>
		// typedef enum _HEAP_INFORMATION_CLASS { HeapCompatibilityInformation = 0, HeapEnableTerminationOnCorruption = 1} HEAP_INFORMATION_CLASS; https://msdn.microsoft.com/en-us/library/windows/desktop/dn280633(v=vs.85).aspx
		[PInvokeData("WinNT.h", MSDNShortId = "dn280633")]
		public enum HEAP_INFORMATION_CLASS
		{
			/// <summary>
			/// <para>
			/// The heap features that are enabled. The available features vary based on operating system. Depending on the HeapInformation parameter in the
			/// <c>HeapQueryInformation</c> or <c>HeapSetInformation</c> functions, specifying this enumeration value can indicate one of the following features:
			/// </para>
			/// <para>For more information about look-aside lists, see the Remarks section.</para>
			/// </summary>
			HeapCompatibilityInformation = 0,
			/// <summary>
			/// <para>
			/// The terminate-on-corruption feature. If the heap manager detects an error in any heap used by the process, it calls the Windows Error Reporting
			/// service and terminates the process.
			/// </para>
			/// <para>After a process enables this feature, it cannot be disabled.</para>
			/// </summary>
			HeapEnableTerminationOnCorruption = 1,
			/// <summary>
			/// If HeapSetInformation is called with HeapHandle set to NULL, then all heaps in the process with a low-fragmentation heap (LFH) will have their
			/// caches optimized, and the memory will be decommitted if possible.
			/// <para>If a heap pointer is supplied in HeapHandle, then only that heap will be optimized.</para>
			/// <para>Note that the HEAP_OPTIMIZE_RESOURCES_INFORMATION structure passed in HeapInformation must be properly initialized.</para>
			/// <para>Note This value was added in Windows 8.1.</para>
			/// </summary>
			HeapOptimizeResources = 3
		}

		/// <summary>Flags for Head functions</summary>
		[PInvokeData("HeapApi.h")]
		[Flags]
		public enum HeapFlags
		{
			/// <summary>
			/// Serialized access will not be used for this allocation. For more information, see Remarks.
			/// <para>
			/// To ensure that serialized access is disabled for all calls to this function, specify HEAP_NO_SERIALIZE in the call to HeapCreate. In this case,
			/// it is not necessary to additionally specify HEAP_NO_SERIALIZE in this function call.
			/// </para>
			/// <para>
			/// This value should not be specified when accessing the process's default heap. The system may create additional threads within the application's
			/// process, such as a CTRL+C handler, that simultaneously access the process's default heap.
			/// </para>
			/// </summary>
			HEAP_NO_SERIALIZE = 0x00000001,
			HEAP_GROWABLE = 0x00000002,
			/// <summary>
			/// The system will raise an exception to indicate a function failure, such as an out-of-memory condition, instead of returning NULL.
			/// <para>
			/// To ensure that exceptions are generated for all calls to this function, specify HEAP_GENERATE_EXCEPTIONS in the call to HeapCreate. In this case,
			/// it is not necessary to additionally specify HEAP_GENERATE_EXCEPTIONS in this function call.
			/// </para>
			/// </summary>
			HEAP_GENERATE_EXCEPTIONS = 0x00000004,
			/// <summary>The allocated memory will be initialized to zero. Otherwise, the memory is not initialized to zero.</summary>
			HEAP_ZERO_MEMORY = 0x00000008,
			/// <summary>
			/// There can be no movement when reallocating a memory block. If this value is not specified, the function may move the block to a new location. If
			/// this value is specified and the block cannot be resized without moving, the function fails, leaving the original memory block unchanged.
			/// </summary>
			HEAP_REALLOC_IN_PLACE_ONLY = 0x00000010,
			HEAP_TAIL_CHECKING_ENABLED = 0x00000020,
			HEAP_FREE_CHECKING_ENABLED = 0x00000040,
			HEAP_DISABLE_COALESCE_ON_FREE = 0x00000080,
			HEAP_CREATE_ALIGN_16 = 0x00010000,
			HEAP_CREATE_ENABLE_TRACING = 0x00020000,
			/// <summary>
			/// All memory blocks that are allocated from this heap allow code execution, if the hardware enforces data execution prevention. Use this flag heap
			/// in applications that run code from the heap. If HEAP_CREATE_ENABLE_EXECUTE is not specified and an application attempts to run code from a
			/// protected page, the application receives an exception with the status code STATUS_ACCESS_VIOLATION.
			/// </summary>
			HEAP_CREATE_ENABLE_EXECUTE = 0x00040000,
			HEAP_MAXIMUM_TAG = 0x0FFF,
			HEAP_PSEUDO_TAG_FLAG = 0x8000,
			HEAP_TAG_SHIFT = 18,
			HEAP_CREATE_SEGMENT_HEAP = 0x00000100,
			HEAP_CREATE_HARDENED = 0x00000200,
		}

		/// <summary>The properties of the heap element.</summary>
		[Flags]
		public enum PROCESS_HEAP : ushort
		{
			/// <summary>
			/// The heap element is located at the beginning of a region of contiguous virtual memory in use by the heap.The lpData member of the structure
			/// points to the first virtual address used by the region; the cbData member specifies the total size, in bytes, of the address space that is
			/// reserved for this region; and the cbOverhead member specifies the size, in bytes, of the heap control structures that describe the region.The
			/// Region structure becomes valid. The dwCommittedSize, dwUnCommittedSize, lpFirstBlock, and lpLastBlock members of the structure contain additional
			/// information about the region.
			/// </summary>
			PROCESS_HEAP_REGION = 1,
			/// <summary>
			/// The heap element is located in a range of uncommitted memory within the heap region.The lpData member points to the beginning of the range of
			/// uncommitted memory; the cbData member specifies the size, in bytes, of the range of uncommitted memory; and the cbOverhead member specifies the
			/// size, in bytes, of the control structures that describe this uncommitted range.
			/// </summary>
			PROCESS_HEAP_UNCOMMITTED_RANGE = 2,
			/// <summary>
			/// The heap element is an allocated block.If PROCESS_HEAP_ENTRY_MOVEABLE is also specified, the Block structure becomes valid. The hMem member of
			/// the Block structure contains a handle to the allocated, moveable memory block.
			/// </summary>
			PROCESS_HEAP_ENTRY_BUSY = 4,
			/// <summary>
			/// This value must be used with PROCESS_HEAP_ENTRY_BUSY, indicating that the heap element is an allocated block.The block was allocated with
			/// LMEM_MOVEABLE or GMEM_MOVEABLE, and the Block structure becomes valid. The hMem member of the Block structure contains a handle to the allocated,
			/// moveable memory block.
			/// </summary>
			PROCESS_HEAP_ENTRY_MOVEABLE = 16,
			/// <summary>This value must be used with PROCESS_HEAP_ENTRY_BUSY, indicating that the heap element is an allocated block.</summary>
			PROCESS_HEAP_ENTRY_DDESHARE = 32,
		}

		/// <summary>Retrieves a handle to the default heap of the calling process. This handle can then be used in subsequent calls to the heap functions.</summary>
		/// <returns>
		/// If the function succeeds, the return value is a handle to the calling process's heap. If the function fails, the return value is NULL. To get
		/// extended error information, call GetLastError.
		/// </returns>
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366569")]
		[DllImport(Lib.Kernel32, ExactSpelling = true, SetLastError = true)]
		public static extern IntPtr GetProcessHeap();

		/// <summary>Returns the number of active heaps and retrieves handles to all of the active heaps for the calling process.</summary>
		/// <param name="NumberOfHeaps">The maximum number of heap handles that can be stored into the buffer pointed to by ProcessHeaps.</param>
		/// <param name="ProcessHeaps">A pointer to a buffer that receives an array of heap handles.</param>
		/// <returns>
		/// <para>The return value is the number of handles to heaps that are active for the calling process.</para>
		/// <para>
		/// If the return value is less than or equal to NumberOfHeaps, the function has stored that number of heap handles in the buffer pointed to by ProcessHeaps.
		/// </para>
		/// <para>
		/// If the return value is greater than NumberOfHeaps, the buffer pointed to by ProcessHeaps is too small to hold all the heap handles for the calling
		/// process, and the function stores NumberOfHeaps handles in the buffer. Use the return value to allocate a buffer that is large enough to receive all
		/// of the handles, and call the function again.
		/// </para>
		/// <para>
		/// If the return value is zero, the function has failed because every process has at least one active heap, the default heap for the process. To get
		/// extended error information, call <c>GetLastError</c>.
		/// </para>
		/// </returns>
		// DWORD WINAPI GetProcessHeaps( _In_ DWORD NumberOfHeaps, _Out_ PHANDLE ProcessHeaps);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366571(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366571")]
		public static extern uint GetProcessHeaps(uint NumberOfHeaps, out IntPtr ProcessHeaps);

		/// <summary>Allocates a block of memory from a heap. The allocated memory is not movable.</summary>
		/// <param name="hHeap">A handle to the heap from which the memory will be allocated. This handle is returned by the HeapCreate or GetProcessHeap function.</param>
		/// <param name="dwFlags">
		/// The heap allocation options. Specifying any of these values will override the corresponding value specified when the heap was created with
		/// HeapCreate. This parameter can be one or more of the following values: HEAP_GENERATE_EXCEPTIONS, HEAP_NO_SERIALIZE and HEAP_ZERO_MEMORY.
		/// </param>
		/// <param name="dwBytes">
		/// The number of bytes to be allocated. If the heap specified by the hHeap parameter is a "non-growable" heap, dwBytes must be less than 0x7FFF8. You
		/// create a non-growable heap by calling the HeapCreate function with a nonzero value.
		/// </param>
		/// <returns>
		/// If the function succeeds, the return value is a pointer to the allocated memory block.
		/// <para>If the function fails and you have not specified HEAP_GENERATE_EXCEPTIONS, the return value is NULL.</para>
		/// <para>
		/// If the function fails and you have specified HEAP_GENERATE_EXCEPTIONS, the function may generate either of the exceptions listed in the following
		/// table. The particular exception depends upon the nature of the heap corruption. For more information, see GetExceptionCode.
		/// </para>
		/// </returns>
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366597")]
		[DllImport(Lib.Kernel32, ExactSpelling = true)]
		public static extern IntPtr HeapAlloc(IntPtr hHeap, HeapFlags dwFlags, [MarshalAs(UnmanagedType.SysInt)] IntPtr dwBytes);

		/// <summary>
		/// Returns the size of the largest committed free block in the specified heap. If the Disable heap coalesce on free global flag is set, this function
		/// also coalesces adjacent free blocks of memory in the heap.
		/// </summary>
		/// <param name="hHeap">A handle to the heap. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.</param>
		/// <param name="dwFlags">
		/// <para>The heap access options. This parameter can be the following value.</para>
		/// <para>
		/// <list type="table">
		/// <listheader>
		/// <term>Value</term>
		/// <term>Meaning</term>
		/// </listheader>
		/// <item>
		/// <term>HEAP_NO_SERIALIZE0x00000001</term>
		/// <term>
		/// Serialized access will not be used. For more information, see Remarks.To ensure that serialized access is disabled for all calls to this function,
		/// specify HEAP_NO_SERIALIZE in the call to HeapCreate. In this case, it is not necessary to additionally specify HEAP_NO_SERIALIZE in this function
		/// call.Do not specify this value when accessing the process heap. The system may create additional threads within the application&amp;#39;s process,
		/// such as a CTRL+C handler, that simultaneously access the process heap.
		/// </term>
		/// </item>
		/// </list>
		/// </para>
		/// </param>
		/// <returns>
		/// <para>If the function succeeds, the return value is the size of the largest committed free block in the heap, in bytes.</para>
		/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
		/// <para>
		/// In the unlikely case that there is absolutely no space available in the heap, the function return value is zero, and <c>GetLastError</c> returns the
		/// value NO_ERROR.
		/// </para>
		/// </returns>
		// SIZE_T WINAPI HeapCompact( _In_ HANDLE hHeap, _In_ DWORD dwFlags);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366598(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366598")]
		public static extern SizeT HeapCompact([In] IntPtr hHeap, HeapFlags dwFlags);

		/// <summary>
		/// Creates a private heap object that can be used by the calling process. The function reserves space in the virtual address space of the process and
		/// allocates physical storage for a specified initial portion of this block.
		/// </summary>
		/// <param name="flOptions">
		/// The heap allocation options. These options affect subsequent access to the new heap through calls to the heap functions. This parameter can be 0 or
		/// one or more of the following values: HEAP_CREATE_ENABLE_EXECUTE, HEAP_GENERATE_EXCEPTIONS, HEAP_NO_SERIALIZE.
		/// </param>
		/// <param name="dwInitialSize">
		/// The initial size of the heap, in bytes. This value determines the initial amount of memory that is committed for the heap. The value is rounded up to
		/// a multiple of the system page size. The value must be smaller than dwMaximumSize.
		/// <para>If this parameter is 0, the function commits one page. To determine the size of a page on the host computer, use the GetSystemInfo function.</para>
		/// </param>
		/// <param name="dwMaximumSize">
		/// The maximum size of the heap, in bytes. The HeapCreate function rounds dwMaximumSize up to a multiple of the system page size and then reserves a
		/// block of that size in the process's virtual address space for the heap. If allocation requests made by the HeapAlloc or HeapReAlloc functions exceed
		/// the size specified by dwInitialSize, the system commits additional pages of memory for the heap, up to the heap's maximum size.
		/// <para>
		/// If dwMaximumSize is not zero, the heap size is fixed and cannot grow beyond the maximum size. Also, the largest memory block that can be allocated
		/// from the heap is slightly less than 512 KB for a 32-bit process and slightly less than 1,024 KB for a 64-bit process. Requests to allocate larger
		/// blocks fail, even if the maximum size of the heap is large enough to contain the block.
		/// </para>
		/// <para>
		/// If dwMaximumSize is 0, the heap can grow in size. The heap's size is limited only by the available memory. Requests to allocate memory blocks larger
		/// than the limit for a fixed-size heap do not automatically fail; instead, the system calls the VirtualAlloc function to obtain the memory that is
		/// needed for large blocks. Applications that need to allocate large memory blocks should set dwMaximumSize to 0.
		/// </para>
		/// </param>
		/// <returns>
		/// If the function succeeds, the return value is a handle to the newly created heap. If the function fails, the return value is NULL. To get extended
		/// error information, call GetLastError.
		/// </returns>
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366599")]
		[DllImport(Lib.Kernel32, ExactSpelling = true, SetLastError = true)]
		public static extern SafePrivateHeapHandle HeapCreate(HeapFlags flOptions, [MarshalAs(UnmanagedType.SysInt)] IntPtr dwInitialSize, [MarshalAs(UnmanagedType.SysInt)] IntPtr dwMaximumSize);

		/// <summary>
		/// Destroys the specified heap object. It decommits and releases all the pages of a private heap object, and it invalidates the handle to the heap.
		/// </summary>
		/// <param name="hHeap">
		/// A handle to the heap to be destroyed. This handle is returned by the HeapCreate function. Do not use the handle to the process heap returned by the
		/// GetProcessHeap function.
		/// </param>
		/// <returns>
		/// If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError.
		/// </returns>
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366700")]
		[DllImport(Lib.Kernel32, ExactSpelling = true, SetLastError = true)]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapDestroy(IntPtr hHeap);

		/// <summary>Frees a memory block allocated from a heap by the HeapAlloc or HeapReAlloc function.</summary>
		/// <param name="hHeap">
		/// A handle to the heap whose memory block is to be freed. This handle is returned by either the HeapCreate or GetProcessHeap function.
		/// </param>
		/// <param name="dwFlags">
		/// The heap free options. Specifying the following value overrides the corresponding value specified in the flOptions parameter when the heap was
		/// created by using the HeapCreate function: HEAP_NO_SERIALIZE
		/// </param>
		/// <param name="lpMem">
		/// A pointer to the memory block to be freed. This pointer is returned by the HeapAlloc or HeapReAlloc function. If this pointer is NULL, the behavior
		/// is undefined.
		/// </param>
		/// <returns>
		/// If the function succeeds, the return value is nonzero. If the function fails, the return value is zero.An application can call GetLastError for
		/// extended error information.
		/// </returns>
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366701")]
		[DllImport(Lib.Kernel32, ExactSpelling = true, SetLastError = true)]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapFree(IntPtr hHeap, HeapFlags dwFlags, IntPtr lpMem);

		/// <summary>Attempts to acquire the critical section object, or lock, that is associated with a specified heap.</summary>
		/// <param name="hHeap">A handle to the heap to be locked. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.</param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
		/// </returns>
		// BOOL WINAPI HeapLock( _In_ HANDLE hHeap);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366702(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366702")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapLock([In] IntPtr hHeap);

		/// <summary>Retrieves information about the specified heap.</summary>
		/// <param name="HeapHandle">
		/// A handle to the heap whose information is to be retrieved. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.
		/// </param>
		/// <param name="HeapInformationClass">
		/// <para>The class of information to be retrieved. This parameter can be the following value from the <c>HEAP_INFORMATION_CLASS</c> enumeration type.</para>
		/// <para>
		/// <list type="table">
		/// <listheader>
		/// <term>Value</term>
		/// <term>Meaning</term>
		/// </listheader>
		/// <item>
		/// <term>HeapCompatibilityInformation0</term>
		/// <term>
		/// Indicates the heap features that are enabled. The HeapInformation parameter is a pointer to a ULONG variable.If HeapInformation is 0, the heap is a
		/// standard heap that does not support look-aside lists.If HeapInformation is 1, the heap supports look-aside lists. For more information, see
		/// Remarks.If HeapInformation is 2, the low-fragmentation heap (LFH) has been enabled for the heap. Enabling the LFH disables look-aside lists.
		/// </term>
		/// </item>
		/// </list>
		/// </para>
		/// </param>
		/// <param name="HeapInformation">
		/// A pointer to a buffer that receives the heap information. The format of this data depends on the value of the HeapInformationClass parameter.
		/// </param>
		/// <param name="HeapInformationLength">The size of the heap information being queried, in bytes.</param>
		/// <param name="ReturnLength">
		/// <para>
		/// A pointer to a variable that receives the length of data written to the HeapInformation buffer. If the buffer is too small, the function fails and
		/// ReturnLength specifies the minimum size required for the buffer.
		/// </para>
		/// <para>If you do not want to receive this information, specify <c>NULL</c>.</para>
		/// </param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
		/// </returns>
		// BOOL WINAPI HeapQueryInformation( _In_opt_ HANDLE HeapHandle, _In_ HEAP_INFORMATION_CLASS HeapInformationClass, _Out_ PVOID HeapInformation, _In_
		// SIZE_T HeapInformationLength, _Out_opt_ PSIZE_T ReturnLength);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366703(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366703")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapQueryInformation([In] IntPtr HeapHandle, HEAP_INFORMATION_CLASS HeapInformationClass, IntPtr HeapInformation, SizeT HeapInformationLength, out SizeT ReturnLength);

		/// <summary>
		/// Reallocates a block of memory from a heap. This function enables you to resize a memory block and change other memory block properties. The allocated
		/// memory is not movable.
		/// </summary>
		/// <param name="hHeap">
		/// A handle to the heap from which the memory is to be reallocated. This handle is a returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.
		/// </param>
		/// <param name="dwFlags">
		/// <para>
		/// The heap reallocation options. Specifying a value overrides the corresponding value specified in the flOptions parameter when the heap was created by
		/// using the <c>HeapCreate</c> function. This parameter can be one or more of the following values.
		/// </para>
		/// <para>
		/// <list type="table">
		/// <listheader>
		/// <term>Value</term>
		/// <term>Meaning</term>
		/// </listheader>
		/// <item>
		/// <term>HEAP_GENERATE_EXCEPTIONS0x00000004</term>
		/// <term>
		/// The operating-system raises an exception to indicate a function failure, such as an out-of-memory condition, instead of returning NULL.To ensure that
		/// exceptions are generated for all calls to this function, specify HEAP_GENERATE_EXCEPTIONS in the call to HeapCreate. In this case, it is not
		/// necessary to additionally specify HEAP_GENERATE_EXCEPTIONS in this function call.
		/// </term>
		/// </item>
		/// <item>
		/// <term>HEAP_NO_SERIALIZE0x00000001</term>
		/// <term>
		/// Serialized access will not be used. For more information, see Remarks.To ensure that serialized access is disabled for all calls to this function,
		/// specify HEAP_NO_SERIALIZE in the call to HeapCreate. In this case, it is not necessary to additionally specify HEAP_NO_SERIALIZE in this function
		/// call.This value should not be specified when accessing the process heap. The system may create additional threads within the application&amp;#39;s
		/// process, such as a CTRL+C handler, that simultaneously access the process heap.
		/// </term>
		/// </item>
		/// <item>
		/// <term>HEAP_REALLOC_IN_PLACE_ONLY0x00000010</term>
		/// <term>
		/// There can be no movement when reallocating a memory block. If this value is not specified, the function may move the block to a new location. If this
		/// value is specified and the block cannot be resized without moving, the function fails, leaving the original memory block unchanged.
		/// </term>
		/// </item>
		/// <item>
		/// <term>HEAP_ZERO_MEMORY0x00000008</term>
		/// <term>
		/// If the reallocation request is for a larger size, the additional region of memory beyond the original size be initialized to zero. The contents of
		/// the memory block up to its original size are unaffected.
		/// </term>
		/// </item>
		/// </list>
		/// </para>
		/// </param>
		/// <param name="lpMem">
		/// A pointer to the block of memory that the function reallocates. This pointer is returned by an earlier call to the <c>HeapAlloc</c> or
		/// <c>HeapReAlloc</c> function.
		/// </param>
		/// <param name="dwBytes">
		/// <para>The new size of the memory block, in bytes. A memory block's size can be increased or decreased by using this function.</para>
		/// <para>
		/// If the heap specified by the hHeap parameter is a "non-growable" heap, dwBytes must be less than 0x7FFF8. You create a non-growable heap by calling
		/// the <c>HeapCreate</c> function with a nonzero value.
		/// </para>
		/// </param>
		/// <returns>
		/// <para>If the function succeeds, the return value is a pointer to the reallocated memory block.</para>
		/// <para>If the function fails and you have not specified <c>HEAP_GENERATE_EXCEPTIONS</c>, the return value is <c>NULL</c>.</para>
		/// <para>
		/// If the function fails and you have specified <c>HEAP_GENERATE_EXCEPTIONS</c>, the function may generate either of the exceptions listed in the
		/// following table. For more information, see <c>GetExceptionCode</c>.
		/// </para>
		/// <para>
		/// <list type="table">
		/// <listheader>
		/// <term>Exception code</term>
		/// <term>Description</term>
		/// </listheader>
		/// <item>
		/// <term>STATUS_NO_MEMORY</term>
		/// <term>The allocation attempt failed because of a lack of available memory or heap corruption.</term>
		/// </item>
		/// <item>
		/// <term>STATUS_ACCESS_VIOLATION</term>
		/// <term>The allocation attempt failed because of heap corruption or improper function parameters.</term>
		/// </item>
		/// </list>
		/// </para>
		/// <para>If the function fails, it does not call <c>SetLastError</c>. An application cannot call <c>GetLastError</c> for extended error information.</para>
		/// </returns>
		// LPVOID WINAPI HeapReAlloc( _In_ HANDLE hHeap, _In_ DWORD dwFlags, _In_ LPVOID lpMem, _In_ SIZE_T dwBytes);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366704(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366704")]
		public static extern IntPtr HeapReAlloc(IntPtr hHeap, HeapFlags dwFlags, IntPtr lpMem, SizeT dwBytes);

		/// <summary>Enables features for a specified heap.</summary>
		/// <param name="HeapHandle">
		/// A handle to the heap where information is to be set. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.
		/// </param>
		/// <param name="HeapInformationClass">
		/// <para>The class of information to be set. This parameter can be one of the following values from the <c>HEAP_INFORMATION_CLASS</c> enumeration type.</para>
		/// <para>
		/// <list type="table">
		/// <listheader>
		/// <term>Value</term>
		/// <term>Meaning</term>
		/// </listheader>
		/// <item>
		/// <term>HeapCompatibilityInformation0</term>
		/// <term>
		/// Enables heap features. Only the low-fragmentation heap (LFH) is supported. However, it is not necessary for applications to enable the LFH because
		/// the system uses the LFH as needed to service memory allocation requests. Windows XP and Windows Server 2003: The LFH is not enabled by default. To
		/// enable the LFH for the specified heap, set the variable pointed to by the HeapInformation parameter to 2. After the LFH is enabled for a heap, it
		/// cannot be disabled.The LFH cannot be enabled for heaps created with HEAP_NO_SERIALIZE or for heaps created with a fixed size. The LFH also cannot be
		/// enabled if you are using the heap debugging tools in Debugging Tools for Windows or Microsoft Application Verifier.When a process is run under any
		/// debugger, certain heap debug options are automatically enabled for all heaps in the process. These heap debug options prevent the use of the LFH. To
		/// enable the low-fragmentation heap when running under a debugger, set the _NO_DEBUG_HEAP environment variable to 1.
		/// </term>
		/// </item>
		/// <item>
		/// <term>HeapEnableTerminationOnCorruption1</term>
		/// <term>
		/// Enables the terminate-on-corruption feature. If the heap manager detects an error in any heap used by the process, it calls the Windows Error
		/// Reporting service and terminates the process.After a process enables this feature, it cannot be disabled.Windows Server 2003 and Windows XP: This
		/// value is not supported until Windows Vista and Windows XP with SP3. The function succeeds but the HeapEnableTerminationOnCorruption value is ignored.
		/// </term>
		/// </item>
		/// <item>
		/// <term>HeapOptimizeResources3</term>
		/// <term>
		/// If HeapSetInformation is called with HeapHandle set to NULL, then all heaps in the process with a low-fragmentation heap (LFH) will have their caches
		/// optimized, and the memory will be decommitted if possible. If a heap pointer is supplied in HeapHandle, then only that heap will be optimized.Note
		/// that the HEAP_OPTIMIZE_RESOURCES_INFORMATION structure passed in HeapInformation must be properly initialized.Note This value was added in Windows 8.1.
		/// </term>
		/// </item>
		/// </list>
		/// </para>
		/// </param>
		/// <param name="HeapInformation">
		/// <para>The heap information buffer. The format of this data depends on the value of the HeapInformationClass parameter.</para>
		/// <para>
		/// If the HeapInformationClass parameter is <c>HeapCompatibilityInformation</c>, the HeapInformation parameter is a pointer to a <c>ULONG</c> variable.
		/// </para>
		/// <para>
		/// If the HeapInformationClass parameter is <c>HeapEnableTerminationOnCorruption</c>, the HeapInformation parameter should be <c>NULL</c> and
		/// HeapInformationLength should be 0
		/// </para>
		/// </param>
		/// <param name="HeapInformationLength">The size of the HeapInformation buffer, in bytes.</param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is 0 (zero). To get extended error information, call <c>GetLastError</c>.</para>
		/// </returns>
		// BOOL WINAPI HeapSetInformation( _In_opt_ HANDLE HeapHandle, _In_ HEAP_INFORMATION_CLASS HeapInformationClass, _In_ PVOID HeapInformation, _In_ SIZE_T
		// HeapInformationLength);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366705(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366705")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapSetInformation([In] IntPtr HeapHandle, HEAP_INFORMATION_CLASS HeapInformationClass, [In] IntPtr HeapInformation, uint HeapInformationLength);

		/// <summary>Retrieves the size of a memory block allocated from a heap by the HeapAlloc or HeapReAlloc function.</summary>
		/// <param name="hHeap">
		/// A handle to the heap in which the memory block resides. This handle is returned by either the HeapCreate or GetProcessHeap function.
		/// </param>
		/// <param name="dwFlags">
		/// The heap size options. Specifying the following value overrides the corresponding value specified in the flOptions parameter when the heap was
		/// created by using the HeapCreate function.
		/// </param>
		/// <param name="lpMem">
		/// A pointer to the memory block whose size the function will obtain. This is a pointer returned by the HeapAlloc or HeapReAlloc function. The memory
		/// block must be from the heap specified by the hHeap parameter.
		/// </param>
		/// <returns>
		/// If the function succeeds, the return value is the requested size of the allocated memory block, in bytes.
		/// <para>
		/// If the function fails, the return value is (SIZE_T)-1. The function does not call SetLastError. An application cannot call GetLastError for extended
		/// error information.
		/// </para>
		/// <para>
		/// If the lpMem parameter refers to a heap allocation that is not in the heap specified by the hHeap parameter, the behavior of the HeapSize function is undefined.
		/// </para>
		/// </returns>
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366706")]
		[DllImport(Lib.Kernel32, ExactSpelling = true, SetLastError = true)]
		[return: MarshalAs(UnmanagedType.SysInt)]
		public static extern IntPtr HeapSize(IntPtr hHeap, HeapFlags dwFlags, IntPtr lpMem);

		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapSummary([In] IntPtr hHeap, HeapFlags dwFlags, out HEAP_SUMMARY lpSummary);

		/// <summary>
		/// Releases ownership of the critical section object, or lock, that is associated with a specified heap. It reverses the action of the <c>HeapLock</c> function.
		/// </summary>
		/// <param name="hHeap">A handle to the heap to be unlocked. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.</param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
		/// </returns>
		// BOOL WINAPI HeapUnlock( _In_ HANDLE hHeap);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366707(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366707")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapUnlock([In] IntPtr hHeap);

		/// <summary>
		/// Validates the specified heap. The function scans all the memory blocks in the heap and verifies that the heap control structures maintained by the
		/// heap manager are in a consistent state. You can also use the <c>HeapValidate</c> function to validate a single memory block within a specified heap
		/// without checking the validity of the entire heap.
		/// </summary>
		/// <param name="hHeap">A handle to the heap to be validated. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.</param>
		/// <param name="dwFlags">
		/// <para>The heap access options. This parameter can be the following value.</para>
		/// <para>
		/// <list type="table">
		/// <listheader>
		/// <term>Value</term>
		/// <term>Meaning</term>
		/// </listheader>
		/// <item>
		/// <term>HEAP_NO_SERIALIZE0x00000001</term>
		/// <term>
		/// Serialized access will not be used. For more information, see Remarks.To ensure that serialized access is disabled for all calls to this function,
		/// specify HEAP_NO_SERIALIZE in the call to HeapCreate. In this case, it is not necessary to additionally specify HEAP_NO_SERIALIZE in this function
		/// call.This value should not be specified when accessing the process default heap. The system may create additional threads within the
		/// application&amp;#39;s process, such as a CTRL+C handler, that simultaneously access the process default heap.
		/// </term>
		/// </item>
		/// </list>
		/// </para>
		/// </param>
		/// <param name="lpMem">
		/// <para>A pointer to a memory block within the specified heap. This parameter may be <c>NULL</c>.</para>
		/// <para>If this parameter is <c>NULL</c>, the function attempts to validate the entire heap specified by hHeap.</para>
		/// <para>
		/// If this parameter is not <c>NULL</c>, the function attempts to validate the memory block pointed to by lpMem. It does not attempt to validate the
		/// rest of the heap.
		/// </para>
		/// </param>
		/// <returns>
		/// <para>If the specified heap or memory block is valid, the return value is nonzero.</para>
		/// <para>
		/// If the specified heap or memory block is invalid, the return value is zero. On a system set up for debugging, the <c>HeapValidate</c> function then
		/// displays debugging messages that describe the part of the heap or memory block that is invalid, and stops at a hard-coded breakpoint so that you can
		/// examine the system to determine the source of the invalidity. The <c>HeapValidate</c> function does not set the thread's last error value. There is
		/// no extended error information for this function; do not call <c>GetLastError</c>.
		/// </para>
		/// </returns>
		// BOOL WINAPI HeapValidate( _In_ HANDLE hHeap, _In_ DWORD dwFlags, _In_opt_ LPCVOID lpMem);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366708(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366708")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapValidate([In] IntPtr hHeap, HeapFlags dwFlags, [In] IntPtr lpMem);

		/// <summary>Enumerates the memory blocks in the specified heap.</summary>
		/// <param name="hHeap">A handle to the heap. This handle is returned by either the <c>HeapCreate</c> or <c>GetProcessHeap</c> function.</param>
		/// <param name="lpEntry">
		/// <para>A pointer to a <c>PROCESS_HEAP_ENTRY</c> structure that maintains state information for a particular heap enumeration.</para>
		/// <para>
		/// If the <c>HeapWalk</c> function succeeds, returning the value <c>TRUE</c>, this structure's members contain information about the next memory block
		/// in the heap.
		/// </para>
		/// <para>
		/// To initiate a heap enumeration, set the <c>lpData</c> field of the <c>PROCESS_HEAP_ENTRY</c> structure to <c>NULL</c>. To continue a particular heap
		/// enumeration, call the <c>HeapWalk</c> function repeatedly, with no changes to hHeap, lpEntry, or any of the members of the <c>PROCESS_HEAP_ENTRY</c> structure.
		/// </para>
		/// </param>
		/// <returns>
		/// <para>If the function succeeds, the return value is nonzero.</para>
		/// <para>If the function fails, the return value is zero. To get extended error information, call <c>GetLastError</c>.</para>
		/// <para>
		/// If the heap enumeration terminates successfully by reaching the end of the heap, the function returns <c>FALSE</c>, and <c>GetLastError</c> returns
		/// the error code <c>ERROR_NO_MORE_ITEMS</c>.
		/// </para>
		/// </returns>
		// BOOL WINAPI HeapWalk( _In_ HANDLE hHeap, _Inout_ LPPROCESS_HEAP_ENTRY lpEntry);// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366710(v=vs.85).aspx
		[DllImport(Lib.Kernel32, SetLastError = true, ExactSpelling = true)]
		[PInvokeData("HeapApi.h", MSDNShortId = "aa366710")]
		[return: MarshalAs(UnmanagedType.Bool)]
		public static extern bool HeapWalk([In] IntPtr hHeap, ref PROCESS_HEAP_ENTRY lpEntry);

		/// <summary>Specifies flags for a HeapOptimizeResources operation initiated with HeapSetInformation.</summary>
		[StructLayout(LayoutKind.Sequential)]
		public struct HEAP_OPTIMIZE_RESOURCES_INFORMATION
		{
			/// <summary>The version</summary>
			public uint Version;
			/// <summary>The flags</summary>
			public uint Flags;
		}

		[StructLayout(LayoutKind.Sequential)]
		public struct HEAP_SUMMARY
		{
			public uint cb;
			public SizeT cbAllocated;
			public SizeT cbCommitted;
			public SizeT cbReserved;
			public SizeT cbMaxReserve;
		}

		/// <summary>
		/// Contains information about a heap element. The <c>HeapWalk</c> function uses a <c>PROCESS_HEAP_ENTRY</c> structure to enumerate the elements of a heap.
		/// </summary>
		// typedef struct _PROCESS_HEAP_ENTRY { PVOID lpData; DWORD cbData; BYTE cbOverhead; BYTE iRegionIndex; WORD wFlags; union { struct { HANDLE hMem; DWORD
		// dwReserved[3]; } Block; struct { DWORD dwCommittedSize; DWORD dwUnCommittedSize; LPVOID lpFirstBlock; LPVOID lpLastBlock; } Region; };}
		// PROCESS_HEAP_ENTRY, *LPPROCESS_HEAP_ENTRY; https://msdn.microsoft.com/en-us/library/windows/desktop/aa366798(v=vs.85).aspx
		[PInvokeData("WinBase.h", MSDNShortId = "aa366798")]
		[StructLayout(LayoutKind.Sequential)]
		public struct PROCESS_HEAP_ENTRY
		{
			/// <summary>
			/// <para>A pointer to the data portion of the heap element.</para>
			/// <para>To initiate a <c>HeapWalk</c> heap enumeration, set <c>lpData</c> to <c>NULL</c>.</para>
			/// <para>If <c>PROCESS_HEAP_REGION</c> is used in the <c>wFlags</c> member, <c>lpData</c> points to the first virtual address used by the region.</para>
			/// <para>If <c>PROCESS_HEAP_UNCOMMITTED_RANGE</c> is used in <c>wFlags</c>, <c>lpData</c> points to the beginning of the range of uncommitted memory.</para>
			/// </summary>
			public IntPtr lpData;
			/// <summary>
			/// <para>The size of the data portion of the heap element, in bytes.</para>
			/// <para>
			/// If <c>PROCESS_HEAP_REGION</c> is used in <c>wFlags</c>, <c>cbData</c> specifies the total size, in bytes, of the address space that is reserved
			/// for this region.
			/// </para>
			/// <para>
			/// If <c>PROCESS_HEAP_UNCOMMITTED_RANGE</c> is used in <c>wFlags</c>, <c>cbData</c> specifies the size, in bytes, of the range of uncommitted memory.
			/// </para>
			/// </summary>
			public uint cbData;
			/// <summary>
			/// <para>
			/// The size of the data used by the system to maintain information about the heap element, in bytes. These overhead bytes are in addition to the
			/// <c>cbData</c> bytes of the data portion of the heap element.
			/// </para>
			/// <para>
			/// If <c>PROCESS_HEAP_REGION</c> is used in <c>wFlags</c>, <c>cbOverhead</c> specifies the size, in bytes, of the heap control structures that
			/// describe the region.
			/// </para>
			/// <para>
			/// If <c>PROCESS_HEAP_UNCOMMITTED_RANGE</c> is used in <c>wFlags</c>, <c>cbOverhead</c> specifies the size, in bytes, of the control structures that
			/// describe this uncommitted range.
			/// </para>
			/// </summary>
			public byte cbOverhead;
			/// <summary>
			/// <para>
			/// A handle to the heap region that contains the heap element. A heap consists of one or more regions of virtual memory, each with a unique region index.
			/// </para>
			/// <para>
			/// In the first heap entry returned for most heap regions, <c>HeapWalk</c> uses the <c>PROCESS_HEAP_REGION</c> in the <c>wFlags</c> member. When
			/// this value is used, the members of the <c>Region</c> structure contain additional information about the region.
			/// </para>
			/// <para>
			/// The <c>HeapAlloc</c> function sometimes uses the <c>VirtualAlloc</c> function to allocate large blocks from a growable heap. The heap manager
			/// treats such a large block allocation as a separate region with a unique region index. <c>HeapWalk</c> does not use <c>PROCESS_HEAP_REGION</c> in
			/// the heap entry returned for a large block region, so the members of the <c>Region</c> structure are not valid. You can use the
			/// <c>VirtualQuery</c> function to get additional information about a large block region.
			/// </para>
			/// </summary>
			public byte iRegionIndex;
			/// <summary>
			/// <para>
			/// The properties of the heap element. Some values affect the meaning of other members of this <c>PROCESS_HEAP_ENTRY</c> data structure. The
			/// following values are defined.
			/// </para>
			/// <para>
			/// <list type="table">
			/// <listheader>
			/// <term>Value</term>
			/// <term>Meaning</term>
			/// </listheader>
			/// <item>
			/// <term>PROCESS_HEAP_ENTRY_BUSY0x0004</term>
			/// <term>
			/// The heap element is an allocated block.If PROCESS_HEAP_ENTRY_MOVEABLE is also specified, the Block structure becomes valid. The hMem member of
			/// the Block structure contains a handle to the allocated, moveable memory block.
			/// </term>
			/// </item>
			/// <item>
			/// <term>PROCESS_HEAP_ENTRY_DDESHARE0x0020</term>
			/// <term>This value must be used with PROCESS_HEAP_ENTRY_BUSY, indicating that the heap element is an allocated block.</term>
			/// </item>
			/// <item>
			/// <term>PROCESS_HEAP_ENTRY_MOVEABLE0x0010</term>
			/// <term>
			/// This value must be used with PROCESS_HEAP_ENTRY_BUSY, indicating that the heap element is an allocated block.The block was allocated with
			/// LMEM_MOVEABLE or GMEM_MOVEABLE, and the Block structure becomes valid. The hMem member of the Block structure contains a handle to the allocated,
			/// moveable memory block.
			/// </term>
			/// </item>
			/// <item>
			/// <term>PROCESS_HEAP_REGION0x0001</term>
			/// <term>
			/// The heap element is located at the beginning of a region of contiguous virtual memory in use by the heap.The lpData member of the structure
			/// points to the first virtual address used by the region; the cbData member specifies the total size, in bytes, of the address space that is
			/// reserved for this region; and the cbOverhead member specifies the size, in bytes, of the heap control structures that describe the region.The
			/// Region structure becomes valid. The dwCommittedSize, dwUnCommittedSize, lpFirstBlock, and lpLastBlock members of the structure contain additional
			/// information about the region.
			/// </term>
			/// </item>
			/// <item>
			/// <term>PROCESS_HEAP_UNCOMMITTED_RANGE0x0002</term>
			/// <term>
			/// The heap element is located in a range of uncommitted memory within the heap region.The lpData member points to the beginning of the range of
			/// uncommitted memory; the cbData member specifies the size, in bytes, of the range of uncommitted memory; and the cbOverhead member specifies the
			/// size, in bytes, of the control structures that describe this uncommitted range.
			/// </term>
			/// </item>
			/// </list>
			/// </para>
			/// </summary>
			public PROCESS_HEAP wFlags;
			/// <summary>A union</summary>
			public BLOCK_REGION_UNION union;

			/// <summary>Union of child structures.</summary>
			[StructLayout(LayoutKind.Explicit)]
			public struct BLOCK_REGION_UNION
			{
				/// <summary>
				/// This structure is valid only if both the <c>PROCESS_HEAP_ENTRY_BUSY</c> and <c>PROCESS_HEAP_ENTRY_MOVEABLE</c> are specified in <c>wFlags</c>.
				/// </summary>
				[FieldOffset(0)]
				public BLOCK_DATA Block;
				/// <summary>This structure is valid only if the <c>wFlags</c> member specifies <c>PROCESS_HEAP_REGION</c>.</summary>
				[FieldOffset(0)]
				public REGION_DATA Region;

				/// <summary>
				/// This structure is valid only if both the <c>PROCESS_HEAP_ENTRY_BUSY</c> and <c>PROCESS_HEAP_ENTRY_MOVEABLE</c> are specified in <c>wFlags</c>.
				/// </summary>
				[StructLayout(LayoutKind.Sequential)]
				public struct BLOCK_DATA
				{
					/// <summary>Handle to the allocated, moveable memory block.</summary>
					public IntPtr hMem;
					/// <summary>Reserved; not used.</summary>
					[MarshalAs(UnmanagedType.ByValArray, SizeConst = 3, ArraySubType = UnmanagedType.U4)]
					public uint[] dwReserved;
				}

				/// <summary>This structure is valid only if the <c>wFlags</c> member specifies <c>PROCESS_HEAP_REGION</c>.</summary>
				[StructLayout(LayoutKind.Sequential)]
				public struct REGION_DATA
				{
					/// <summary>
					/// Number of bytes in the heap region that are currently committed as free memory blocks, busy memory blocks, or heap control structures.
					/// This is an optional field that is set to zero if the number of committed bytes is not available.
					/// </summary>
					public uint dwCommittedSize;
					/// <summary>
					/// Number of bytes in the heap region that are currently uncommitted. This is an optional field that is set to zero if the number of
					/// uncommitted bytes is not available.
					/// </summary>
					public uint dwUnCommittedSize;
					/// <summary>Pointer to the first valid memory block in this heap region.</summary>
					public IntPtr lpFirstBlock;
					/// <summary>Pointer to the first invalid memory block in this heap region.</summary>
					public IntPtr lpLastBlock;
				}
			}
		}

		/// <summary>Safe handle for memory heaps.</summary>
		/// <seealso cref="Vanara.InteropServices.GenericSafeHandle"/>
		public class SafePrivateHeapBlockHandle : GenericSafeHandle
		{
			private SafePrivateHeapHandle hHeap;

			/// <summary>Initializes a new instance of the <see cref="SafePrivateHeapBlockHandle"/> class.</summary>
			public SafePrivateHeapBlockHandle(SafePrivateHeapHandle hHeap) : this(hHeap, IntPtr.Zero) { }

			/// <summary>Initializes a new instance of the <see cref="SafePrivateHeapBlockHandle"/> class.</summary>
			/// <param name="hHeap">A handle to a heap created using <see cref="HeapCreate"/>.</param>
			/// <param name="ptr">The handle created by <see cref="HeapAlloc"/>.</param>
			/// <param name="own">if set to <c>true</c> this safe handle disposes the handle when done.</param>
			public SafePrivateHeapBlockHandle(SafePrivateHeapHandle hHeap, IntPtr ptr, bool own = true) : base(ptr, h => HeapFree(hHeap, 0, h), own)
			{
				this.hHeap = hHeap;
			}

			/// <summary>
			/// Initializes a new instance of the <see cref="SafePrivateHeapBlockHandle"/> class and allocates the specified amount of memory from the process heap.
			/// </summary>
			/// <param name="hHeap">A handle to a heap created using <see cref="HeapCreate"/>.</param>
			/// <param name="size">The size. This value cannot be zero.</param>
			public SafePrivateHeapBlockHandle(SafePrivateHeapHandle hHeap, int size) : this(hHeap, HeapAlloc(hHeap, HeapFlags.HEAP_ZERO_MEMORY, (IntPtr)size)) { }

			/// <summary>Retrieves the size of this memory block.</summary>
			/// <value>The size in bytes of this memory block.</value>
			public long Size => HeapSize(hHeap, 0, handle).ToInt64();
		}

		/// <summary>Safe handle for memory heaps.</summary>
		/// <seealso cref="Vanara.InteropServices.GenericSafeHandle"/>
		public class SafePrivateHeapHandle : GenericSafeHandle
		{
			/// <summary>Initializes a new instance of the <see cref="SafePrivateHeapHandle"/> class.</summary>
			public SafePrivateHeapHandle() : this(IntPtr.Zero) { }

			/// <summary>Initializes a new instance of the <see cref="SafePrivateHeapHandle"/> class.</summary>
			/// <param name="ptr">The handle created by <see cref="HeapCreate"/>.</param>
			/// <param name="own">if set to <c>true</c> this safe handle disposes the handle when done.</param>
			public SafePrivateHeapHandle(IntPtr ptr, bool own = true) : base(ptr, HeapDestroy, own) { }

			/// <summary>Gets a block of memory from this private heap.</summary>
			/// <param name="size">The size of the block.</param>
			/// <returns>A safe handle for the memory that will call HeapFree on disposal.</returns>
			public SafePrivateHeapBlockHandle GetBlock(int size) => new SafePrivateHeapBlockHandle(this, size);
		}

		/// <summary>Safe handle for memory heaps.</summary>
		/// <seealso cref="Vanara.InteropServices.GenericSafeHandle"/>
		public class SafeProcessHeapBlockHandle : GenericSafeHandle
		{
			/// <summary>Initializes a new instance of the <see cref="SafeProcessHeapBlockHandle"/> class.</summary>
			public SafeProcessHeapBlockHandle() : this(IntPtr.Zero) { }

			/// <summary>Initializes a new instance of the <see cref="SafeProcessHeapBlockHandle"/> class.</summary>
			/// <param name="ptr">The handle created by <see cref="HeapAlloc"/>.</param>
			/// <param name="own">if set to <c>true</c> this safe handle disposes the handle when done.</param>
			public SafeProcessHeapBlockHandle(IntPtr ptr, bool own = true) : base(ptr, h => HeapFree(GetProcessHeap(), 0, h), own) { }

			/// <summary>
			/// Initializes a new instance of the <see cref="SafeProcessHeapBlockHandle"/> class and allocates the specified amount of memory from the process heap.
			/// </summary>
			/// <param name="size">The size. This value cannot be zero.</param>
			public SafeProcessHeapBlockHandle(ulong size) : this(HeapAlloc(GetProcessHeap(), HeapFlags.HEAP_ZERO_MEMORY, (IntPtr)size)) { }

			/// <summary>Retrieves the size of this memory block.</summary>
			/// <value>The size in bytes of this memory block.</value>
			public long Size => HeapSize(GetProcessHeap(), 0, handle).ToInt64();
		}
	}
}