SQUASHFS/squashfs-tools-4.4/squashfs-tools/swap.c

   1 /*
   2  * Copyright (c) 2009, 2010
   3  * Phillip Lougher <phillip@squashfs.org.uk>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2,
   8  * or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  *
  19  * swap.c
  20  */
  21
  22 #ifndef linux
  23 #define __BYTE_ORDER BYTE_ORDER
  24 #define __BIG_ENDIAN BIG_ENDIAN
  25 #define __LITTLE_ENDIAN LITTLE_ENDIAN
  26 #else
  27 #include <endian.h>
  28 #endif
  29
  30 #if __BYTE_ORDER == __BIG_ENDIAN
  31 void swap_le16(void *src, void *dest)
  32 {
  33         unsigned char *s = src;
  34         unsigned char *d = dest;
  35
  36         d[0] = s[1];
  37         d[1] = s[0];
  38 }
  39
  40
  41 void swap_le32(void *src, void *dest)
  42 {
  43         unsigned char *s = src;
  44         unsigned char *d = dest;
  45
  46         d[0] = s[3];
  47         d[1] = s[2];
  48         d[2] = s[1];
  49         d[3] = s[0];
  50 }
  51
  52
  53 void swap_le64(void *src, void *dest)
  54 {
  55         unsigned char *s = src;
  56         unsigned char *d = dest;
  57
  58         d[0] = s[7];
  59         d[1] = s[6];
  60         d[2] = s[5];
  61         d[3] = s[4];
  62         d[4] = s[3];
  63         d[5] = s[2];
  64         d[6] = s[1];
  65         d[7] = s[0];
  66 }
  67
  68
  69 unsigned short inswap_le16(unsigned short num)
  70 {
  71         return (num >> 8) |
  72                 ((num & 0xff) << 8);
  73 }
  74
  75
  76 unsigned int inswap_le32(unsigned int num)
  77 {
  78         return (num >> 24) |
  79                 ((num & 0xff0000) >> 8) |
  80                 ((num & 0xff00) << 8) |
  81                 ((num & 0xff) << 24);
  82 }
  83
  84
  85 long long inswap_le64(long long n)
  86 {
  87         unsigned long long num = n;
  88
  89         return (num >> 56) |
  90                 ((num & 0xff000000000000LL) >> 40) |
  91                 ((num & 0xff0000000000LL) >> 24) |
  92                 ((num & 0xff00000000LL) >> 8) |
  93                 ((num & 0xff000000) << 8) |
  94                 ((num & 0xff0000) << 24) |
  95                 ((num & 0xff00) << 40) |
  96                 ((num & 0xff) << 56);
  97 }
  98
  99
 100 #define SWAP_LE_NUM(BITS) \
 101 void swap_le##BITS##_num(void *s, void *d, int n) \
 102 {\
 103         int i;\
 104         for(i = 0; i < n; i++, s += BITS / 8, d += BITS / 8)\
 105                 swap_le##BITS(s, d);\
 106 }
 107
 108 SWAP_LE_NUM(16)
 109 SWAP_LE_NUM(32)
 110 SWAP_LE_NUM(64)
 111
 112 #define INSWAP_LE_NUM(BITS, TYPE) \
 113 void inswap_le##BITS##_num(TYPE *s, int n) \
 114 {\
 115         int i;\
 116         for(i = 0; i < n; i++)\
 117                 s[i] = inswap_le##BITS(s[i]);\
 118 }
 119
 120 INSWAP_LE_NUM(16, unsigned short)
 121 INSWAP_LE_NUM(32, unsigned int)
 122 INSWAP_LE_NUM(64, long long)
 123 #endif