calloc.cpp

ICEExt for Driver Studio3.2的sourcecode

// this file is slightly modified version from MS VC 6.0 CRT Sources.
// .\libmad\layer3.c needs calloc() function so I implement it here

/***
*void *calloc(size_t num, size_t size) - allocate storage for an array from
*       the heap
*
*Purpose:
*       Allocate a block of memory from heap big enough for an array of num
*       elements of size bytes each, initialize all bytes in the block to 0
*       and return a pointer to it.
*
*Entry:
*       size_t num  - number of elements in the array
*       size_t size - size of each element
*
*Exit:
*       Success:  void pointer to allocated block block
*       Failure:  NULL
*
*Uses:
*
*Exceptions:
*
*******************************************************************************/
extern "C" {
#pragma warning ( push, 3 )
#include <ntddk.h>
#pragma warning ( pop )
}

#pragma warning ( disable: 4514 ) // unreferenced inline function has been removed
#pragma warning ( disable: 4273 ) // inconsistent dll linkage.  dllexport assumed.

#include <malloc.h>

void * __cdecl calloc (
        size_t num,
        size_t size
        )
{
        void *retp;
        size_t *startptr;
        size_t *lastptr;

        /* try to malloc the requested space
         */
        retp = malloc(size *= num);

        /* if malloc() succeeded, initialize the allocated space to zeros.
         * note the assumptions that the size of the allocation block is an
         * integral number of sizeof(size_t) bytes and that (size_t)0 is
         * sizeof(size_t) bytes of 0.
         */

        if ( retp != NULL ) {
            startptr = (size_t *)retp;
            lastptr = startptr + ((size + sizeof(size_t) - 1) /
            sizeof(size_t));
            while ( startptr < lastptr )
                *(startptr++) = 0;
        }

        return retp;
}