xref: /dflybsd-src/contrib/gcc-4.7/libstdc++-v3/libsupc++/hash_bytes.h (revision 04febcfb30580676d3e95f58a16c5137ee478b32)
1*e4b17023SJohn Marino // Declarations for hash functions. -*- C++ -*-
2*e4b17023SJohn Marino 
3*e4b17023SJohn Marino // Copyright (C) 2010, 2011 Free Software Foundation, Inc.
4*e4b17023SJohn Marino //
5*e4b17023SJohn Marino // This file is part of the GNU ISO C++ Library.  This library is free
6*e4b17023SJohn Marino // software; you can redistribute it and/or modify it under the
7*e4b17023SJohn Marino // terms of the GNU General Public License as published by the
8*e4b17023SJohn Marino // Free Software Foundation; either version 3, or (at your option)
9*e4b17023SJohn Marino // any later version.
10*e4b17023SJohn Marino 
11*e4b17023SJohn Marino // This library is distributed in the hope that it will be useful,
12*e4b17023SJohn Marino // but WITHOUT ANY WARRANTY; without even the implied warranty of
13*e4b17023SJohn Marino // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14*e4b17023SJohn Marino // GNU General Public License for more details.
15*e4b17023SJohn Marino 
16*e4b17023SJohn Marino // Under Section 7 of GPL version 3, you are granted additional
17*e4b17023SJohn Marino // permissions described in the GCC Runtime Library Exception, version
18*e4b17023SJohn Marino // 3.1, as published by the Free Software Foundation.
19*e4b17023SJohn Marino 
20*e4b17023SJohn Marino // You should have received a copy of the GNU General Public License and
21*e4b17023SJohn Marino // a copy of the GCC Runtime Library Exception along with this program;
22*e4b17023SJohn Marino // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23*e4b17023SJohn Marino // <http://www.gnu.org/licenses/>.
24*e4b17023SJohn Marino 
25*e4b17023SJohn Marino /** @file bits/hash_bytes.h
26*e4b17023SJohn Marino  *  This is an internal header file, included by other library headers.
27*e4b17023SJohn Marino  *  Do not attempt to use it directly. @headername{functional}
28*e4b17023SJohn Marino  */
29*e4b17023SJohn Marino 
30*e4b17023SJohn Marino #ifndef _HASH_BYTES_H
31*e4b17023SJohn Marino #define _HASH_BYTES_H 1
32*e4b17023SJohn Marino 
33*e4b17023SJohn Marino #pragma GCC system_header
34*e4b17023SJohn Marino 
35*e4b17023SJohn Marino #include <bits/c++config.h>
36*e4b17023SJohn Marino 
37*e4b17023SJohn Marino namespace std
38*e4b17023SJohn Marino {
39*e4b17023SJohn Marino _GLIBCXX_BEGIN_NAMESPACE_VERSION
40*e4b17023SJohn Marino 
41*e4b17023SJohn Marino   // Hash function implementation for the nontrivial specialization.
42*e4b17023SJohn Marino   // All of them are based on a primitive that hashes a pointer to a
43*e4b17023SJohn Marino   // byte array. The actual hash algorithm is not guaranteed to stay
44*e4b17023SJohn Marino   // the same from release to release -- it may be updated or tuned to
45*e4b17023SJohn Marino   // improve hash quality or speed.
46*e4b17023SJohn Marino   size_t
47*e4b17023SJohn Marino   _Hash_bytes(const void* __ptr, size_t __len, size_t __seed);
48*e4b17023SJohn Marino 
49*e4b17023SJohn Marino   // A similar hash primitive, using the FNV hash algorithm. This
50*e4b17023SJohn Marino   // algorithm is guaranteed to stay the same from release to release.
51*e4b17023SJohn Marino   // (although it might not produce the same values on different
52*e4b17023SJohn Marino   // machines.)
53*e4b17023SJohn Marino   size_t
54*e4b17023SJohn Marino   _Fnv_hash_bytes(const void* __ptr, size_t __len, size_t __seed);
55*e4b17023SJohn Marino 
56*e4b17023SJohn Marino _GLIBCXX_END_NAMESPACE_VERSION
57*e4b17023SJohn Marino } // namespace
58*e4b17023SJohn Marino 
59*e4b17023SJohn Marino #endif
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