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revision 1.6, Wed Jun 12 20:38:41 2002 UTC revision 1.15.2.2, Mon Jun 9 13:55:38 2003 UTC
# Line 1  Line 1 
1    /*****************************************************************************
2     *
3     *  XVID MPEG-4 VIDEO CODEC
4     *  - Aligned Memory Allocator -
5     *
6     *  Copyright(C) 2002-2003 Edouard Gomez <ed.gomez@free.fr>
7     *
8     *  This program is free software ; you can redistribute it and/or modify
9     *  it under the terms of the GNU General Public License as published by
10     *  the Free Software Foundation ; either version 2 of the License, or
11     *  (at your option) any later version.
12     *
13     *  This program is distributed in the hope that it will be useful,
14     *  but WITHOUT ANY WARRANTY ; without even the implied warranty of
15     *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16     *  GNU General Public License for more details.
17     *
18     *  You should have received a copy of the GNU General Public License
19     *  along with this program ; if not, write to the Free Software
20     *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
21     *
22     * $Id$
23     *
24     ****************************************************************************/
25    
26  #include <stdlib.h>  #include <stdlib.h>
27  #include <stdio.h>  #include <stdio.h>
28  #include "mem_align.h"  #include "mem_align.h"
29    
30    /*****************************************************************************
31     * xvid_malloc
32     *
33     * This function allocates 'size' bytes (usable by the user) on the heap and
34     * takes care of the requested 'alignment'.
35     * In order to align the allocated memory block, the xvid_malloc allocates
36     * 'size' bytes + 'alignment' bytes. So try to keep alignment very small
37     * when allocating small pieces of memory.
38     *
39     * NB : a block allocated by xvid_malloc _must_ be freed with xvid_free
40     *      (the libc free will return an error)
41     *
42     * Returned value : - NULL on error
43     *                  - Pointer to the allocated aligned block
44     *
45     ****************************************************************************/
46    
47  void *  void *
48  xvid_malloc(size_t size,  xvid_malloc(size_t size,
49                          uint8_t alignment)                          uint8_t alignment)
# Line 14  Line 56 
56                  if ((mem_ptr = (uint8_t *) malloc(size + 1)) != NULL) {                  if ((mem_ptr = (uint8_t *) malloc(size + 1)) != NULL) {
57    
58                          /* Store (mem_ptr - "real allocated memory") in *(mem_ptr-1) */                          /* Store (mem_ptr - "real allocated memory") in *(mem_ptr-1) */
59                          *mem_ptr = 0;                          *mem_ptr = 1;
60    
61                          /* Return the mem_ptr pointer */                          /* Return the mem_ptr pointer */
62                          return (void *) mem_ptr++;                          return (void *)(mem_ptr+1);
63    
64                  }                  }
65    
# Line 33  Line 75 
75    
76                          /* Align the tmp pointer */                          /* Align the tmp pointer */
77                          mem_ptr =                          mem_ptr =
78                                  (uint8_t *) ((uint32_t) (tmp + alignment - 1) &                                  (uint8_t *) ((ptr_t) (tmp + alignment - 1) &
79                                                           (~(uint32_t) (alignment - 1)));                                                           (~(ptr_t) (alignment - 1)));
80    
81                          /*                          /*
82                           * Special case where malloc have already satisfied the alignment                           * Special case where malloc have already satisfied the alignment
# Line 62  Line 104 
104    
105  }  }
106    
107    /*****************************************************************************
108     * xvid_free
109     *
110     * Free a previously 'xvid_malloc' allocated block. Does not free NULL
111     * references.
112     *
113     * Returned value : None.
114     *
115     ****************************************************************************/
116    
117  void  void
118  xvid_free(void *mem_ptr)  xvid_free(void *mem_ptr)
119  {  {
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