Source code of Windows XP (NT5)
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//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1992 - 1993.
//
// File: stdalloc.cxx
//
// Contents: 16-bit OLE allocator
//
// Classes:
//
// Functions:
//
// History: 3-07-94 kevinro Ported from ole2.01 (16-bit)
//
//----------------------------------------------------------------------------
#include <headers.cxx>
#pragma hdrstop
#include <ole2sp.h>
/****** Standard Task/Shared Allocator **********************************/
#define NULLSAB ((__segment)0)
typedef __segment SAB;
// amount of space windows reserves at start of segment
#define cbWinRes 16
// amount of space LocalInit takes (somewhat empirical)
#define cbWinOH (6+10+46)
// total overhead per global block
#define cbTotalOH (cbWinRes + sizeof(StdAllocHdr) + cbWinOH + 32)
// maximum sized object in a SAB (fudged to include space for per-block
// overhead and most anything else we missed).
#define cbMaxSAB (0xfffe - cbTotalOH)
//+---------------------------------------------------------------------------
//
// Class: CStdMalloc ()
//
// Purpose: Standard task allocator
//
// History: 3-04-94 kevinro Created
//
// Notes:
//
//----------------------------------------------------------------------------
class FAR CStdMalloc : public IMalloc
{
public:
CStdMalloc(DWORD memctx)
{
m_refs = 1;
m_pStdAllocHead = NULL;
m_flags = (memctx == MEMCTX_TASK)? GMEM_MOVEABLE :
GMEM_MOVEABLE|GMEM_SHARE;
}
STDMETHOD(QueryInterface)(REFIID iid, void FAR* FAR* ppvObj)
{
VDATEPTROUT( ppvObj, LPVOID );
*ppvObj = NULL;
VDATEIID( iid );
if (iid == IID_IUnknown || iid == IID_IMalloc) {
*ppvObj = this;
++m_refs;
return NOERROR;
} else {
*ppvObj = NULL;
return ReportResult(0, E_NOINTERFACE, 0, 0);
}
}
STDMETHOD_(ULONG,AddRef)(void) { return ++m_refs; }
STDMETHOD_(ULONG,Release)(void)
{
if (--m_refs == 0) {
// free all memory (includes the memory for this class)
FreeAllMem();
return 0;
} else
return m_refs;
}
STDMETHOD_(void FAR*, Alloc) (ULONG cb);
STDMETHOD_(void FAR*, Realloc) (void FAR* pv, ULONG cb);
STDMETHOD_(void, Free) (void FAR* pv);
STDMETHOD_(ULONG, GetSize) (void FAR* pv);
STDMETHOD_(int, DidAlloc) (void FAR* pv);
STDMETHOD_(void, HeapMinimize) ();
private:
ULONG m_refs;
UINT m_flags;
#define STDALLOC_SIG 0x4D445453 // 'STDM'
struct StdAllocHdr
{
ULONG m_Signature;
HTASK m_hTask; // task which owns this block
StdAllocHdr FAR* m_pStdAllocNext;
};
StdAllocHdr FAR* m_pStdAllocHead;
INTERNAL_(StdAllocHdr FAR*) MapBlockToSA(SAB sab) { return (StdAllocHdr FAR*)MAKELONG(cbWinRes, sab); }
INTERNAL_(SAB) MapSAToBlock(StdAllocHdr FAR* pSA) { return (__segment)pSA; }
INTERNAL_(void FAR*) AllocInBlock(SAB seg, UINT cb);
INTERNAL_(SAB) AllocNewBlock(UINT cb);
INTERNAL_(SAB) MapPtrToBlock(void FAR* pv);
INTERNAL_(CStdMalloc FAR*) MoveSelf(LPVOID lpv);
friend HRESULT STDAPICALLTYPE CoCreateStandardMalloc(DWORD memctx, IMalloc FAR* FAR* ppMalloc);
INTERNAL_(void) FreeAllMem(void);
};
INTERNAL_(void FAR*) CStdMalloc::AllocInBlock(SAB sab, UINT cb)
{
#ifdef _DEBUG
WINDEBUGINFO Olddebuginfo, debuginfo;
//get initial debug state
GetWinDebugInfo(&debuginfo, WDI_OPTIONS);
Olddebuginfo = debuginfo;
//turn off alerts (see bug 3502)
debuginfo.dwOptions |= DBO_SILENT;
SetWinDebugInfo(&debuginfo);
#endif // _DEBUG
// must make alloc of 0 mean alloc something; LocalAlloc fails on cb == 0
if (0==cb)
cb = 2;
_asm push DS;
_asm mov DS, sab;
void NEAR *npv = (void NEAR*)LocalAlloc(LMEM_FIXED, cb);
_asm pop DS;
#ifdef _DEBUG
//restore Debug state
SetWinDebugInfo(&Olddebuginfo);
#endif // _DEBUG
if (npv == NULL) // npv is near pointer
return NULL; // returned value is far pointer
return (void FAR*)MAKELONG(npv, sab);
}
INTERNAL_(SAB) CStdMalloc::AllocNewBlock(UINT cb)
{
if (cb > cbMaxSAB)
// overflow
return NULLSAB;
if (cb < 4096 - cbTotalOH)
// minimum is 4k global block
cb = 4096;
else
// size will be larger than 4K; must include total overhead
cb += cbTotalOH;
// allocate block and get segment value
HGLOBAL h;
if ((h = GlobalAlloc(m_flags, cb)) == NULL)
return NULLSAB;
UINT segment;
segment = HIWORD(GlobalHandle(h));
// init windows local heap
if (!LocalInit(segment, cbWinRes + sizeof(StdAllocHdr), cb)) {
GlobalFree(h);
return NULLSAB;
}
// init block and put it on front of list
StdAllocHdr FAR* pSA;
pSA = MapBlockToSA((SAB)segment);
pSA->m_Signature = STDALLOC_SIG;
pSA->m_hTask = (m_flags & GMEM_SHARE) != 0 ? NULL : GetCurrentTask();
pSA->m_pStdAllocNext = m_pStdAllocHead;
m_pStdAllocHead = pSA;
return (SAB)segment;
}
INTERNAL_(SAB) CStdMalloc::MapPtrToBlock(void FAR* pv)
{
if (pv == NULL)
return NULLSAB;
StdAllocHdr FAR* pSA;
pSA = MapBlockToSA((SAB)pv);
if (pSA->m_Signature != STDALLOC_SIG)
return NULLSAB;
#ifdef DOESNTWORK
UINT flags = GlobalFlags((HGLOBAL)GlobalHandle((SAB)pv));
#endif
if (m_flags & GMEM_SHARE) {
if (pSA->m_hTask != NULL)
// owned by task; not shared memory
return NULLSAB;
#ifdef DOESNTWORK
if ((flags & GMEM_SHARE) == 0)
// flags not shared, not shared memory
return NULLSAB;
#endif
} else {
if (pSA->m_hTask != GetCurrentTask()) {
// if not same task, not this allocator; if different task,
// something is wrong.
AssertSz(pSA->m_hTask == NULL, "pointer used in wrong task");
return NULLSAB;
}
#ifdef DOESNTWORK
if ((flags & GMEM_SHARE) != 0)
// flags shared, not task memory
return NULLSAB;
#endif
}
return MapSAToBlock(pSA);
}
STDMETHODIMP_(void FAR*) CStdMalloc::Alloc(ULONG cb)
{
if (cb > cbMaxSAB)
// can't deal with objects larger than 64k
return NULL;
// try all sab in order (newest allocated sab on front)
StdAllocHdr FAR* pSA = m_pStdAllocHead;
while (pSA != NULL) {
// try allocating the memory; if successful, return
void FAR* pv;
if ((pv = AllocInBlock(MapSAToBlock(pSA), (UINT)cb)) != NULL)
return pv;
pSA = pSA->m_pStdAllocNext;
}
SAB sab;
if ((sab = AllocNewBlock((UINT)cb)) == NULLSAB)
return NULL;
// this should really succeed (i.e., an assert would be better)
return AllocInBlock(sab, (UINT)cb);
}
STDMETHODIMP_(void FAR*) CStdMalloc::Realloc(void FAR* pv, ULONG cb)
{
if (cb > cbMaxSAB)
// can't deal with objects larger than 64k
return NULL;
SAB sab;
if (pv == NULL)
// same as allocating a new pointer
return Alloc(cb);
//VDATEPTRIN rejects NULL (changed by alexgo 8/3/93)
GEN_VDATEPTRIN( pv, int, (LPVOID)NULL );
if ((sab = MapPtrToBlock(pv)) == NULLSAB)
// attempt to realloc a pointer from some other allocator
return NULL;
else if (cb == 0) {
// Realloc(pv, 0) -> frees and returns NULL; this is C library behavior
Free(pv);
return NULL;
}
void NEAR* npv;
npv = (void NEAR*)(ULONG)pv;
// first try realloc within same sab
Assert(sab != NULLSAB);
{
void NEAR* npvT;
_asm push DS;
_asm mov DS, sab;
npvT = (void NEAR*)LocalReAlloc((HLOCAL)npv, (UINT)cb, LMEM_MOVEABLE);
_asm pop DS;
if (npvT != NULL)
return (void FAR*)MAKELONG(npvT, sab);
}
// now try allocating new sab and copying
void FAR* pvT;
if ((pvT = Alloc(cb)) == NULL)
return NULL;
// only copy the smaller of the old and new size
_asm push ds;
_asm mov ds,sab;
UINT cbCopy = LocalSize((HLOCAL)npv);
_asm pop ds;
if ((UINT)cb < cbCopy)
// new size smaller
cbCopy = (UINT)cb;
_fmemcpy(pvT, pv, cbCopy);
Free(pv);
return pvT;
}
STDMETHODIMP_(void) CStdMalloc::Free(void FAR* pv)
{
SAB sab;
if (pv == NULL)
return;
//VDATEPTRIN rejects NULL (changed by alexgo 8/3/93)
VOID_VDATEPTRIN( pv, int );
if ((sab = MapPtrToBlock(pv)) == NULLSAB) {
#ifdef _DEBUG
AssertSz(FALSE, "Pointer freed by wrong allocator; filling with 0xcc");
// we don't own block; this is an error; fill it with 0xcccc anyway
UINT cb = (UINT)GlobalSize((HGLOBAL)GlobalHandle((__segment)pv));
cb -= (UINT)(ULONG)pv;
_fmemset(pv, 0xcc, (size_t)cb);
#endif
} else {
#ifdef _DEBUG
// we own block; fill it with 0xcccc
_fmemset(pv, 0xcc, (size_t)GetSize(pv));
#endif
_asm push ds;
_asm mov ds,sab;
LocalFree((HLOCAL)(void NEAR*)(ULONG)pv);
_asm pop ds;
}
}
STDMETHODIMP_(ULONG) CStdMalloc::GetSize(void FAR* pv)
{
ULONG size = 0;
SAB sab;
//VDATEPTRIN rejects NULL (added by alexgo 8/3/93)
if( pv == NULL )
return -1;
GEN_VDATEPTRIN( pv , int, 0 );
if ((sab = MapPtrToBlock(pv)) != NULLSAB) {
_asm push ds;
_asm mov ds,sab;
size = LocalSize((HLOCAL)(void NEAR*)(ULONG)pv);
_asm pop ds;
}
return size;
}
STDMETHODIMP_(int) CStdMalloc::DidAlloc(void FAR* pv)
{
if (pv == NULL)
return -1;
//VDATEPTRIN rejects NULL (added by alexgo 8/3/93)
GEN_VDATEPTRIN( pv , int, 0 );
// returns 1 if we allocated, 0 if not; this impl never returns -1.
return MapPtrToBlock(pv) != NULLSAB;
}
STDMETHODIMP_(void) CStdMalloc::HeapMinimize()
{
// LATER : could do local compact here
}
// move this instance of stdmalloc to lpv (which must be large enough)
INTERNAL_(CStdMalloc FAR*) CStdMalloc::MoveSelf(LPVOID lpv)
{
_fmemcpy(lpv, this, sizeof(*this));
m_pStdAllocHead = NULL;
return (CStdMalloc FAR*)lpv;
}
INTERNAL_(void) CStdMalloc::FreeAllMem(void)
{
// get/null out head of list; null now in case we are freeing self.
StdAllocHdr FAR* pSA = m_pStdAllocHead;
m_pStdAllocHead = NULL;
// free all blocks
while (pSA != NULL) {
StdAllocHdr FAR* pSANext = pSA->m_pStdAllocNext;
pSA->m_pStdAllocNext = NULL; // to prevent incorrect compiler opt
GlobalFree(LOWORD(GlobalHandle((UINT)MapSAToBlock(pSA))));
pSA = pSANext;
}
}
/****** Global API for creating *****************************************/
// create and return an impl of IMalloc of given memctx
//+---------------------------------------------------------------------------
//
// Function: CoCreateStandardMalloc, Local
//
// Synopsis:
//
// Effects:
//
// Arguments: [memctx] --
// [ppMalloc] --
//
// Requires:
//
// Returns:
//
// Signals:
//
// Modifies:
//
// Algorithm:
//
// History: 2-28-94 kevinro Created
//
// Notes:
//
//----------------------------------------------------------------------------
STDAPI CoCreateStandardMalloc(DWORD memctx, IMalloc FAR* FAR* ppMalloc)
{
thkDebugOut((DEB_ITRACE, " CoCreateStandardMalloc\n"));
*ppMalloc = NULL;
switch (memctx) {
case MEMCTX_TASK:
case MEMCTX_SHARED:
{
CStdMalloc sm(memctx); // local one
void FAR* lpv;
if ((lpv = sm.Alloc(sizeof(CStdMalloc))) == NULL)
return ResultFromScode(E_OUTOFMEMORY);
*ppMalloc = sm.MoveSelf(lpv); // move to newly allocated memory
return NOERROR;
}
default:
return ResultFromScode(E_INVALIDARG);
}
}