--- mem_align.c 2002/12/28 13:53:08 1.14 +++ mem_align.c 2004/03/22 22:36:24 1.16 @@ -1,57 +1,25 @@ /***************************************************************************** * * XVID MPEG-4 VIDEO CODEC - * - Aligned memory allocator - + * - Aligned Memory Allocator - * - * Copyright(C) 2002 Michael Militzer - * 2002 Edouard Gomez + * Copyright(C) 2002-2003 Edouard Gomez * - * This file is part of XviD, a free MPEG-4 video encoder/decoder - * - * XviD is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or + * This program is free software ; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation ; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of + * but WITHOUT ANY WARRANTY ; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software + * along with this program ; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * - * Under section 8 of the GNU General Public License, the copyright - * holders of XVID explicitly forbid distribution in the following - * countries: - * - * - Japan - * - United States of America - * - * Linking XviD statically or dynamically with other modules is making a - * combined work based on XviD. Thus, the terms and conditions of the - * GNU General Public License cover the whole combination. - * - * As a special exception, the copyright holders of XviD give you - * permission to link XviD with independent modules that communicate with - * XviD solely through the VFW1.1 and DShow interfaces, regardless of the - * license terms of these independent modules, and to copy and distribute - * the resulting combined work under terms of your choice, provided that - * every copy of the combined work is accompanied by a complete copy of - * the source code of XviD (the version of XviD used to produce the - * combined work), being distributed under the terms of the GNU General - * Public License plus this exception. An independent module is a module - * which is not derived from or based on XviD. - * - * Note that people who make modified versions of XviD are not obligated - * to grant this special exception for their modified versions; it is - * their choice whether to do so. The GNU General Public License gives - * permission to release a modified version without this exception; this - * exception also makes it possible to release a modified version which - * carries forward this exception. - * - * $Id: mem_align.c,v 1.14 2002/12/28 13:53:08 edgomez Exp $ + * $Id: mem_align.c,v 1.16 2004/03/22 22:36:24 edgomez Exp $ * ****************************************************************************/ @@ -88,21 +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 */ @@ -110,30 +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); } /***************************************************************************** @@ -150,8 +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); }