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// -*-c++-*-
/* $Id: keyfunc.h,v 1.5 2001/07/18 03:02:17 dm Exp $ */
/*
*
* Copyright (C) 1998 David Mazieres (dm@uun.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*/
#ifndef _KEYFUNC_H_
#define _KEYFUNC_H_ 1
template<class T> struct unref_t {
typedef T base_type;
typedef T unref_type;
typedef const T &ref_type;
typedef T &ncref_type;
};
template<class T> struct unref_t<const T> {
typedef T base_type;
typedef const T unref_type;
typedef const T &ref_type;
typedef T &ncref_type;
};
template<class T> struct unref_t<T &> {
typedef T base_type;
typedef T unref_type;
typedef const T &ref_type;
typedef T &ncref_type;
};
template<class T> struct unref_t<const T &> {
typedef T base_type;
typedef const T unref_type;
typedef const T &ref_type;
typedef T &ncref_type;
};
#define CREF(T) unref_t<T>::ref_type
#define UNREF(T) unref_t<T>::unref_type
#define UNCREF(T) unref_t<T>::base_type
#define NCREF(T) unref_t<T>::ncref_type
#define HASHSEED 5381
inline u_int
hash_bytes (const void *_key, int len, u_int seed = HASHSEED)
{
const u_char *key = (const u_char *) _key;
const u_char *end;
for (end = key + len; key < end; key++)
seed = ((seed << 5) + seed) ^ *key;
return seed;
}
inline u_int
hash_string (const void *_p, u_int v = HASHSEED)
{
const char *p = (const char *) _p;
while (*p)
v = (33 * v) ^ (unsigned char) *p++;
return v;
}
inline u_int
hash_rotate (u_int val, u_int rot)
{
rot %= 8 * sizeof (val);
return (val << rot) | (val >> (8 * sizeof (val) - rot));
}
class hash_t {
u_int val;
public:
hash_t () {}
hash_t (u_int v) : val (v) {}
operator u_int() const { return val; }
};
template<class T>
struct compare {
compare () {}
int operator() (CREF (T) a, CREF (T) b) const
{ return a < b ? -1 : b < a; }
};
template<class T>
struct compare<const T> : compare<T>
{
compare () {}
};
template<class T>
struct equals {
equals () {}
bool operator() (CREF (T) a, CREF (T) b) const
{ return a == b; }
};
template<class T>
struct equals<const T> : equals<T>
{
equals () {}
};
template<class T>
struct hashfn {
hashfn () {}
hash_t operator() (CREF (T) a) const
{ return a; }
};
template<class T>
struct hashfn<const T> : hashfn<T>
{
hashfn () {}
};
template<class T1, class T2>
struct hash2fn {
hashfn<T1> h1;
hashfn<T2> h2;
hash2fn () {}
hash_t operator() (CREF (T1) t1, CREF (T2) t2) const
{ return h1 (t1) ^ h2 (t2); }
};
/* Don't compare pointers by accident */
template<class T> struct compare<T *>;
template<class T> struct hashfn<T *>;
/* Specializations for (char *) */
#define _CHAR_PTR(T, u) \
template<> \
struct compare<T> { \
compare () {} \
int operator() (const u char *a, const u char *b) const \
{ return strcmp ((char *) a, (char *) b); } \
}; \
template<> \
struct equals<T> { \
equals () {} \
bool operator() (const u char *a, const u char *b) const \
{ return !strcmp ((char *) a, (char *) b); } \
}; \
template<> \
struct hashfn<T> { \
hashfn () {} \
hash_t operator() (const u char *a) const \
{ return hash_string (a); } \
};
#define CHAR_PTR(T, u) _CHAR_PTR(T, u) _CHAR_PTR(T const, u)
CHAR_PTR(char *,)
CHAR_PTR(const char *,)
CHAR_PTR(signed char *, signed)
CHAR_PTR(const signed char *, signed)
CHAR_PTR(unsigned char *, unsigned)
CHAR_PTR(const unsigned char *, unsigned)
template<class R, class V, class K, K V::*key, class F>
class keyfunc_1 {
public:
const F kf;
keyfunc_1 () {}
keyfunc_1 (const F &f) : kf (f) {}
R operator() (CREF (V) a) const
{ return kf (a.*key); }
};
template<class R, class V, class K, K V::*key, class F>
class keyfunc_2 {
public:
const F kf;
keyfunc_2 () {}
keyfunc_2 (const F &f) : kf (f) {}
R operator() (CREF (V) a, CREF (V) b) const
{ return kf (a.*key, b.*key); }
};
#endif /* !KEYFUNC_H_ */
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