Xapian: Internal Source Documentation: xapian-core: common/unaligned.h Source File

00001 /* unaligned.h: Read/write unaligned 1, 2, 4 byte integers.
00002  *
00003  * Copyright 1999,2000,2001 BrightStation PLC
00004  * Copyright 2002,2004,2008 Olly Betts
00005  *
00006  * This program is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU General Public License as
00008  * published by the Free Software Foundation; either version 2 of the
00009  * License, or (at your option) any later version.
00010  *
00011  * This program is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  * GNU General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU General Public License
00017  * along with this program; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
00019  * USA
00020  */
00021 
00022 #ifndef XAPIAN_INCLUDED_UNALIGNED_H
00023 #define XAPIAN_INCLUDED_UNALIGNED_H
00024 
00025 #include "omassert.h"
00026 
00027 // FIXME: 65536 in Asserts below is the max flint/chert block size.  We should
00028 // abstract this out, and use the current block_size to catch overruns better.
00029 inline int
00030 getint1(const unsigned char *p, int c)
00031 {
00032     AssertRel(c, >=, 0);
00033     AssertRel(c, <, 65536);
00034     return p[c];
00035 }
00036 
00037 inline void
00038 setint1(unsigned char *p, int c, int x)
00039 {
00040     AssertRel(c, >=, 0);
00041     AssertRel(c, <, 65536);
00042     p[c] = static_cast<unsigned char>(x);
00043 }
00044 
00045 inline int
00046 getint2(const unsigned char *p, int c)
00047 {
00048     AssertRel(c, >=, 0);
00049     AssertRel(c, <, 65536 - 1);
00050     return p[c] << 8 | p[c + 1];
00051 }
00052 
00053 inline void
00054 setint2(unsigned char *p, int c, int x)
00055 {
00056     AssertRel(c, >=, 0);
00057     AssertRel(c, <, 65536 - 1);
00058     p[c] = static_cast<unsigned char>(x >> 8);
00059     p[c + 1] = static_cast<unsigned char>(x);
00060 }
00061 
00062 inline int
00063 getint4(const unsigned char *p, int c)
00064 {
00065     AssertRel(c, >=, 0);
00066     AssertRel(c, <, 65536 - 3);
00067     return p[c] << 24 | p[c + 1] << 16 | p[c + 2] << 8 | p[c + 3];
00068 }
00069 
00070 inline void
00071 setint4(unsigned char *p, int c, int x)
00072 {
00073     AssertRel(c, >=, 0);
00074     AssertRel(c, <, 65536 - 3);
00075     p[c] = static_cast<unsigned char>(x >> 24);
00076     p[c + 1] = static_cast<unsigned char>(x >> 16);
00077     p[c + 2] = static_cast<unsigned char>(x >> 8);
00078     p[c + 3] = static_cast<unsigned char>(x);
00079 }
00080 
00081 #endif // XAPIAN_INCLUDED_UNALIGNED_H