ceph/branches/sage/pgs/include/blobhash.h
sageweil 9213a23f14 eek
git-svn-id: https://ceph.svn.sf.net/svnroot/ceph@1138 29311d96-e01e-0410-9327-a35deaab8ce9
2007-02-28 18:42:55 +00:00

46 lines
1020 B
C++

// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef __BLOBHASH_H
#define __BLOBHASH_H
/*
- this is to make some of the STL types work with 64 bit values, string hash keys, etc.
- added when i was using an old STL.. maybe try taking these out and see if things
compile now?
*/
class blobhash {
public:
size_t operator()(const char *p, unsigned len) {
static hash<long> H;
long acc = 0;
while (len >= sizeof(long)) {
acc ^= *(long*)p;
p += sizeof(long);
len -= sizeof(long);
}
int sh = 0;
while (len) {
acc ^= (long)*p << sh;
sh += 8;
len--;
p++;
}
return H(acc);
}
};
#endif