--- mem_align.c 2003/06/09 13:55:38 1.15.2.2 +++ mem_align.c 2003/09/29 00:30:31 1.15.2.3 @@ -19,7 +19,7 @@ * along with this program ; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * - * $Id: mem_align.c,v 1.15.2.2 2003/06/09 13:55:38 edgomez Exp $ + * $Id: mem_align.c,v 1.15.2.3 2003/09/29 00:30:31 edgomez Exp $ * ****************************************************************************/ @@ -56,21 +56,16 @@ if ((mem_ptr = (uint8_t *) malloc(size + 1)) != NULL) { /* Store (mem_ptr - "real allocated memory") in *(mem_ptr-1) */ - *mem_ptr = 1; + *mem_ptr = (uint8_t)1; /* Return the mem_ptr pointer */ - return (void *)(mem_ptr+1); - + return ((void *)(mem_ptr+1)); } - } else { uint8_t *tmp; - /* - * Allocate the required size memory + alignment so we - * can realign the data if necessary - */ - + /* 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 */ @@ -78,30 +73,24 @@ (uint8_t *) ((ptr_t) (tmp + alignment - 1) & (~(ptr_t) (alignment - 1))); - /* - * Special case where malloc have already satisfied the alignment + /* 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 - */ + * 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 - 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 ((void *)mem_ptr); } } - return NULL; - + return(NULL); } /***************************************************************************** @@ -118,8 +107,18 @@ xvid_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)); + uint8_t *ptr; + + if (mem_ptr == NULL) + return; + + /* Aligned pointer */ + ptr = mem_ptr; + + /* *(ptr - 1) holds the offset to the real allocated block + * we sub that offset os we free the real pointer */ + ptr -= *(ptr - 1); + /* Free the memory */ + free(ptr); }