#include <stdlib.h>#include <stdio.h>#include "mem_align.h"void *xvid_malloc(size_t size,			uint8_t alignment){	uint8_t *mem_ptr;	if (!alignment) {		/* We have not to satisfy any alignment */		if ((mem_ptr = (uint8_t *) malloc(size + 1)) != NULL) {			/* Store (mem_ptr - "real allocated memory") in *(mem_ptr-1) */			*mem_ptr = 0;			/* Return the mem_ptr pointer */			return (void *) mem_ptr++;		}	} else {		uint8_t *tmp;		/*		 * Allocate the required size memory + alignment so we		 * can realign the data if necessary		 */		if ((tmp = (uint8_t *) malloc(size + alignment)) != NULL) {			/* Align the tmp pointer */			mem_ptr =				(uint8_t *) ((ptr_t) (tmp + alignment - 1) &							 (~(ptr_t) (alignment - 1)));			/*			 * Special case where malloc have already satisfied the alignment			 * We must add alignment to mem_ptr because we must store			 * (mem_ptr - tmp) in *(mem_ptr-1)			 * If we do not add alignment to mem_ptr then *(mem_ptr-1) points			 * to a forbidden memory space			 */			if (mem_ptr == tmp)				mem_ptr += alignment;			/*			 * (mem_ptr - tmp) is stored in *(mem_ptr-1) so we are able to retrieve			 * the real malloc block allocated and free it in xvid_free			 */			*(mem_ptr - 1) = (uint8_t) (mem_ptr - tmp);			/* Return the aligned pointer */			return (void *) mem_ptr;		}	}	return NULL;}/***************************************************************************** * xvid_free * * Free a previously 'xvid_malloc' allocated block. Does not free NULL * references. * * Returned value : None. * ****************************************************************************/voidxvid_free(void *mem_ptr){	/* *(mem_ptr - 1) give us the offset to the real malloc block */	if (mem_ptr)		free((uint8_t *) mem_ptr - *((uint8_t *) mem_ptr - 1));}