Source code of Windows XP (NT5)
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/*++
Copyright (c) 1997-2000 Microsoft Corporation
Module Name:
memory.c
Abstract:
Domain Name System (DNS) Library
Memory allocation routines for DNS library.
Author:
Jim Gilroy (jamesg) January, 1997
Revision History:
--*/
#include "local.h"
//
// Memory allocation
//
// Some DNS library functions -- including the IP array and string utils
// -- allocate memory. This memory allocation defaults to routines that
// use LocalAlloc, LocalReAlloc, LocalFree.
//
// Dns_Api.dll users can reset the memory allocation through
// Dns_ApiHeapReset(), which saves pointers to remote allocation functions
// which will override default allocators.
//
//
// Allow overide of default memory allocation
//
DNSLIB_ALLOC_FUNCTION pDnsAllocFunction = NULL;
DNSLIB_REALLOC_FUNCTION pDnsReallocFunction = NULL;
DNSLIB_FREE_FUNCTION pDnsFreeFunction = NULL;
VOID
Dns_LibHeapReset(
IN DNSLIB_ALLOC_FUNCTION pAlloc,
IN DNSLIB_REALLOC_FUNCTION pRealloc,
IN DNSLIB_FREE_FUNCTION pFree
)
/*++
Routine Description:
Resets heap routines used by dnsapi.dll routines.
Arguments:
pAlloc -- ptr to desired alloc function
pRealloc -- ptr to desired realloc function
pFree -- ptr to desired free function
Return Value:
None.
--*/
{
pDnsAllocFunction = pAlloc;
pDnsReallocFunction = pRealloc;
pDnsFreeFunction = pFree;
}
//
// Exported public memory routines.
//
// These use whatever the current memory allocation routines are, and
// hence will always handle memory in the same fashion as dnsapi.dll
// internal routines.
//
PVOID
Dns_Alloc(
IN INT iSize
)
/*++
Routine Description:
Allocates memory.
Arguments:
iSize - number of bytes to allocate
Return Value:
Pointer to memory allocated.
NULL if allocation fails.
--*/
{
if ( pDnsAllocFunction )
{
return (*pDnsAllocFunction)( iSize );
}
// default
return LocalAlloc( LPTR, iSize );
}
PVOID
Dns_Realloc(
IN OUT PVOID pMem,
IN INT iSize
)
/*++
Routine Description:
Reallocates memory
Arguments:
pMem - ptr to existing memory to reallocated
iSize - number of bytes to reallocate
Return Value:
Pointer to memory allocated.
NULL if allocation fails.
--*/
{
if ( pDnsReallocFunction )
{
return (*pDnsReallocFunction)( pMem, iSize );
}
// default
return LocalReAlloc( pMem, iSize, 0 );
}
VOID
Dns_Free(
IN OUT PVOID pMem
)
/*++
Routine Description:
Free memory
Arguments:
pMem - ptr to existing memory to reallocated
Return Value:
None
--*/
{
if ( !pMem )
{
return;
}
if ( pDnsFreeFunction )
{
(*pDnsFreeFunction)( pMem );
return;
}
// default
LocalFree( pMem );
}
PVOID
Dns_AllocZero(
IN INT iSize
)
/*++
Routine Description:
Allocates and zeros memory.
Arguments:
iSize - number of bytes to allocate
Return Value:
Pointer to memory allocated.
NULL if allocation fails.
--*/
{
if ( pDnsAllocFunction )
{
PCHAR ptr;
ptr = (*pDnsAllocFunction)( iSize );
if ( !ptr )
{
return( NULL );
}
RtlZeroMemory( ptr, iSize );
return( ptr );
}
// default
return LocalAlloc( LPTR, iSize );
}
//
// Helpful util
//
PVOID
Dns_AllocMemCopy(
IN PVOID pMem,
IN INT Size
)
/*++
Routine Description:
Allocates and copies memory
Arguments:
pMem - memory to copy
Size - number of bytes to allocate
Return Value:
Pointer to memory allocated.
NULL if allocation fails.
--*/
{
PBYTE ptr;
ptr = Dns_Alloc( Size );
if ( ptr )
{
if ( pMem )
{
RtlCopyMemory(
ptr,
pMem,
Size );
}
else
{
RtlZeroMemory( ptr, Size );
}
}
return ptr;
}
//
// End of memory.c
//