xapian-core/common/unaligned.h

   1 /** @file unaligned.h
   2  * @brief Read/write unaligned 1, 2, 4 byte integers.
   3  */
   4 /* Copyright 1999,2000,2001 BrightStation PLC
   5  * Copyright 2002,2004,2008,2011 Olly Betts
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
  20  * USA
  21  */
  22
  23 #ifndef XAPIAN_INCLUDED_UNALIGNED_H
  24 #define XAPIAN_INCLUDED_UNALIGNED_H
  25
  26 #include "omassert.h"
  27
  28 // FIXME: 65536 in Asserts below is the max chert block size.  We should
  29 // abstract this out, and use the current block_size to catch overruns better.
  30 inline int
  31 getint1(const unsigned char *p, int c)
  32 {
  33     AssertRel(c, >=, 0);
  34     AssertRel(c, <, 65536);
  35     return p[c];
  36 }
  37
  38 inline void
  39 setint1(unsigned char *p, int c, int x)
  40 {
  41     AssertRel(c, >=, 0);
  42     AssertRel(c, <, 65536);
  43     p[c] = static_cast<unsigned char>(x);
  44 }
  45
  46 inline int
  47 getint2(const unsigned char *p, int c)
  48 {
  49     AssertRel(c, >=, 0);
  50     AssertRel(c, <, 65536 - 1);
  51     return p[c] << 8 | p[c + 1];
  52 }
  53
  54 inline void
  55 setint2(unsigned char *p, int c, int x)
  56 {
  57     AssertRel(c, >=, 0);
  58     AssertRel(c, <, 65536 - 1);
  59     p[c] = static_cast<unsigned char>(x >> 8);
  60     p[c + 1] = static_cast<unsigned char>(x);
  61 }
  62
  63 inline int
  64 getint4(const unsigned char *p, int c)
  65 {
  66     AssertRel(c, >=, 0);
  67     AssertRel(c, <, 65536 - 3);
  68     return p[c] << 24 | p[c + 1] << 16 | p[c + 2] << 8 | p[c + 3];
  69 }
  70
  71 inline void
  72 setint4(unsigned char *p, int c, int x)
  73 {
  74     AssertRel(c, >=, 0);
  75     AssertRel(c, <, 65536 - 3);
  76     p[c] = static_cast<unsigned char>(x >> 24);
  77     p[c + 1] = static_cast<unsigned char>(x >> 16);
  78     p[c + 2] = static_cast<unsigned char>(x >> 8);
  79     p[c + 3] = static_cast<unsigned char>(x);
  80 }
  81
  82 #endif // XAPIAN_INCLUDED_UNALIGNED_H