130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
/*****************************************************************************
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*
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* DIMem.c
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*
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* Copyright (c) 1996 - 1999 Microsoft Corporation. All Rights Reserved.
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*
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* Abstract:
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*
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* Memory management
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*
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* Contents:
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*
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* ReallocCbPpv
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* AllocCbPpv
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* FreePpv
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*
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*****************************************************************************/
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#include "dinputpr.h"
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#ifdef NEED_REALLOC
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/*****************************************************************************
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*
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* ReallocCbPpv
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*
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* Change the size of some zero-initialized memory.
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*
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* This is the single place where all memory is allocated, resized,
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* and freed.
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*
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* If you realloc from a null pointer, memory is allocated.
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* If you realloc to zero-size, memory is freed.
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*
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* These semantics avoid boundary cases. For example, it is no
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* longer a problem trying to realloc something down to zero.
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* You don't have to worry about special-casing an alloc of 0 bytes.
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*
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* If an error is returned, the original pointer is UNCHANGED.
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* This saves you from having to the double-switch around a realloc.
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*
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*****************************************************************************/
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STDMETHODIMP EXTERNAL
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ReallocCbPpv(UINT cb, PV ppvArg)
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{
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HRESULT hres;
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PPV ppv = ppvArg;
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HLOCAL hloc = *ppv;
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if (cb) { /* Alloc or realloc */
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if (hloc) { /* Realloc */
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hloc = LocalReAlloc(hloc, cb,
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LMEM_MOVEABLE+LMEM_ZEROINIT);
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} else { /* Alloc */
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hloc = LocalAlloc(LPTR, cb);
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}
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hres = hloc ? NOERROR : E_OUTOFMEMORY;
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} else { /* Freeing */
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if (hloc) {
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LocalFree(hloc);
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hloc = 0;
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hres = NOERROR; /* All gone */
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} else {
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hres = NOERROR; /* Nothing to free */
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}
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}
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if (SUCCEEDED(hres)) {
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*ppv = hloc;
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}
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return hres;
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}
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/*****************************************************************************
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*
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* AllocCbPpv
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*
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* Simple wrapper that forces *ppvObj = 0 before calling Realloc.
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*
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*****************************************************************************/
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STDMETHODIMP EXTERNAL
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AllocCbPpv(UINT cb, PPV ppv)
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{
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*ppv = 0;
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return ReallocCbPpv(cb, ppv);
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}
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#else
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/*****************************************************************************
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*
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* AllocCbPpv
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*
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* Allocate memory into the ppv.
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*
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*****************************************************************************/
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STDMETHODIMP EXTERNAL
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AllocCbPpv(UINT cb, PPV ppv)
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{
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HRESULT hres;
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*ppv = LocalAlloc(LPTR, cb);
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hres = *ppv ? NOERROR : E_OUTOFMEMORY;
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return hres;
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}
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/*****************************************************************************
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*
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* FreePpv
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*
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* Free memory from the ppv.
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*
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*****************************************************************************/
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void EXTERNAL
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FreePpv(PV ppv)
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{
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#ifdef _M_IA64
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PV pv = (PV)InterlockedExchange64(ppv, 0);
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#else
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PV pv = (PV)InterlockedExchange(ppv, 0);
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#endif
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if (pv) {
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FreePv(pv);
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}
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}
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#endif
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