reactos/dll/win32/kernel32/include/baseheap.h

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/*
* PROJECT: ReactOS Win32 Base API
* LICENSE: GPL - See COPYING in the top level directory
* FILE: dll/win32/kernel32/include/baseheap.h
* PURPOSE: Base Heap Structures
* PROGRAMMERS: Alex Ionescu (alex.ionescu@reactos.org)
*/
//
// Some important implementation notes.
//
// Firstly, the Global* APIs in Win32 are largely similar to the Local* APIs,
// but there are a number of small differences (for example, there is no such
// thing as DDE/Shared Local memory, and the re-allocation semantics are also
// simpler, because you cannot force a move).
//
// Note something VERY IMPORTANT: This implementation *depends* on the fact
// that all heap pointers are, at the very least, 8 byte aligned, and that heap
// handles are actually pointers inside our HandleEntry->Object, which happens
// to be at offset 0x4, which means testing with bit 3 tells us if the handle
// is a pointer or a real "handle". On 64-bit, heap pointers should be 16-byte
// aligned, and our offset should be 0x8, so the trick works anyways, but using
// the 4th bit.
//
// Apart from MSDN, a wonderful source of information about how this works is
// available on Raymond's blog, in a 4-parter series starting at:
// http://blogs.msdn.com/oldnewthing/archive/2004/11/04/252258.aspx.
//
// Finally, as Raymond points out, be aware that some applications depend on
// the way this implementation was done, since global memory handles are a
// straight-forward overlay on top of the RTL Handle implementation, and rogue
// applications can easily do the conversion manually without calling the right
// API for it (such as GlobalLock).
//
// Tracing Support
// Define _BASE_HANDLE_TRACE for Traces
//
#ifdef _BASE_HANDLE_TRACE_
#define BH_PRINT DbgPrint
#else
#define BH_PRINT DPRINT
#endif
#define BASE_TRACE_ALLOC(x, y) \
BH_PRINT("[BASE_HEAP] %s : Allocating %lx bytes with flags: %lx\n", \
__FUNCTION__, x, y)
#define BASE_TRACE_ALLOC2(x) \
BH_PRINT("[BASE_HEAP] %s : Allocated %p\n", \
__FUNCTION__, x)
#define BASE_TRACE_PTR(x, y) \
BH_PRINT("[BASE_HEAP] %s : Using handle: %p for pointer: %p\n", \
__FUNCTION__, x, y)
#define BASE_TRACE_HANDLE(x, y) \
BH_PRINT("[BASE_HEAP] %s : Using handle: %lx for block: %p\n", \
__FUNCTION__, x, y)
#define BASE_TRACE_DEALLOC(x) \
BH_PRINT("[BASE_HEAP] %s : Freeing %p\n", \
__FUNCTION__, x)
#define BASE_TRACE_FAILURE() \
BH_PRINT("[BASE_HEAP] %s : Failing %d\n", \
__FUNCTION__, __LINE__)
//
// The handle structure for global heap handles.
// Notice that it nicely overlays with RTL_HANDLE_ENTRY.
// KEEP IT THAT WAY! ;-)
//
typedef struct _BASE_HEAP_HANDLE_ENTRY
{
USHORT Flags;
USHORT LockCount;
union
{
PVOID Object;
ULONG OldSize;
};
} BASE_HEAP_HANDLE_ENTRY, *PBASE_HEAP_HANDLE_ENTRY;
//
// Handle entry flags
// Note that 0x0001 is the shared/generic RTL_HANDLE_VALID
//
#define BASE_HEAP_ENTRY_FLAG_MOVABLE 0x0002
#define BASE_HEAP_ENTRY_FLAG_REUSABLE 0x0004
#define BASE_HEAP_ENTRY_FLAG_REUSE 0x0008
#define BASE_HEAP_ENTRY_FLAG_DDESHARE 0x0010
//
// Easy way to check if the global handle is actually an entry in our table
//
#define BASE_HEAP_IS_HANDLE_ENTRY \
(ULONG_PTR)FIELD_OFFSET(BASE_HEAP_HANDLE_ENTRY, Object)
//
// Tags for the entire heap allocation for this global memory.
// They are set part of the User Flags of the RTL Heap.
//
#define BASE_HEAP_FLAG_MOVABLE HEAP_SETTABLE_USER_FLAG1
#define BASE_HEAP_FLAG_DDESHARE HEAP_SETTABLE_USER_FLAG2
//
// Internal Handle Functions
//
#define BaseHeapAllocEntry() \
(PBASE_HEAP_HANDLE_ENTRY)RtlAllocateHandle(&BaseHeapHandleTable, NULL)
#define BaseHeapGetEntry(h) \
(PBASE_HEAP_HANDLE_ENTRY) \
CONTAINING_RECORD(h, \
BASE_HEAP_HANDLE_ENTRY, \
Object);
#define BaseHeapValidateEntry(he) \
RtlIsValidHandle(&BaseHeapHandleTable, (PRTL_HANDLE_TABLE_ENTRY)he)
#define BaseHeapFreeEntry(he) \
RtlFreeHandle(&BaseHeapHandleTable, (PRTL_HANDLE_TABLE_ENTRY)he);