lib/cdb++/internal.h
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     1 // Copyright (C) 1999,2000 Bruce Guenter <bruceg@em.ca>
       
     2 //
       
     3 // This program is free software; you can redistribute it and/or modify
       
     4 // it under the terms of the GNU General Public License as published by
       
     5 // the Free Software Foundation; either version 2 of the License, or
       
     6 // (at your option) any later version.
       
     7 //
       
     8 // This program is distributed in the hope that it will be useful,
       
     9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
       
    10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
       
    11 // GNU General Public License for more details.
       
    12 //
       
    13 // You should have received a copy of the GNU General Public License
       
    14 // along with this program; if not, write to the Free Software
       
    15 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
       
    16 
       
    17 #ifndef CDBXX__INTERNAL__H__
       
    18 #define CDBXX__INTERNAL__H__
       
    19 
       
    20 #include "cdb++.h"
       
    21 
       
    22 #define CDB_HASHSTART ((uint32) 5381)
       
    23 
       
    24 inline void pack(unsigned char* buf, uint32 num)
       
    25 {
       
    26     *buf++ = num; num >>= 8;
       
    27     *buf++ = num; num >>= 8;
       
    28     *buf++ = num; num >>= 8;
       
    29     *buf = num;
       
    30 }
       
    31 
       
    32 inline uint32 unpack(const unsigned char* p)
       
    33 {
       
    34   return uint32(p[0]) |
       
    35     uint32(p[1]) << 8 |
       
    36     uint32(p[2]) << 16 |
       
    37     uint32(p[3]) << 24;
       
    38 }
       
    39 
       
    40 inline uint32 hash(const mystring& s)
       
    41 {
       
    42   uint32 h = CDB_HASHSTART;
       
    43   const char* p = s.c_str();
       
    44   for(unsigned len = s.length(); len > 0; len--)
       
    45     h = ((h << 5) + h) ^ *p++;
       
    46   return h;
       
    47 }
       
    48 
       
    49 #endif