dict/lookup.c

   1 /* This file is part of the Zebra server.
   2    Copyright (C) 1994-2011 Index Data
   3
   4 Zebra is free software; you can redistribute it and/or modify it under
   5 the terms of the GNU General Public License as published by the Free
   6 Software Foundation; either version 2, or (at your option) any later
   7 version.
   8
   9 Zebra is distributed in the hope that it will be useful, but WITHOUT ANY
  10 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17
  18 */
  19
  20
  21
  22 #if HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <stdio.h>
  28 #include <assert.h>
  29
  30 #include "dict-p.h"
  31
  32 static char *dict_look(Dict dict, const Dict_char *str, Dict_ptr ptr)
  33 {
  34     int mid, lo, hi;
  35     int cmp;
  36     void *p;
  37     short *indxp;
  38     char *info;
  39
  40     dict_bf_readp(dict->dbf, ptr, &p);
  41     mid = lo = 0;
  42     hi = DICT_nodir(p)-1;
  43     indxp = (short*) ((char*) p+DICT_bsize(p)-sizeof(short));
  44     while (lo <= hi)
  45     {
  46         mid = (lo+hi)/2;
  47         if (indxp[-mid] > 0)
  48         {
  49             /* string (Dict_char *) DICT_EOS terminated */
  50             /* unsigned char        length of information */
  51             /* char *               information */
  52             info = (char*)p + indxp[-mid];
  53             cmp = dict_strcmp((Dict_char*) info, str);
  54             if (!cmp)
  55                 return info+(dict_strlen ((Dict_char*) info)+1)
  56                     *sizeof(Dict_char);
  57         }
  58         else
  59         {
  60             Dict_char dc;
  61             Dict_ptr subptr;
  62
  63             /* Dict_ptr             subptr */
  64             /* Dict_char            sub char */
  65             /* unsigned char        length of information */
  66             /* char *               information */
  67             info = (char*)p - indxp[-mid];
  68             memcpy(&dc, info+sizeof(Dict_ptr), sizeof(Dict_char));
  69             cmp = dc- *str;
  70             if (!cmp)
  71             {
  72                 memcpy(&subptr, info, sizeof(Dict_ptr));
  73                 if (*++str == DICT_EOS)
  74                 {
  75                     if (info[sizeof(Dict_ptr)+sizeof(Dict_char)])
  76                         return info+sizeof(Dict_ptr)+sizeof(Dict_char);
  77                     return NULL;
  78                 }
  79                 else
  80                 {
  81                     if (subptr == 0)
  82                         return NULL;
  83                     ptr = subptr;
  84                     dict_bf_readp(dict->dbf, ptr, &p);
  85                     mid = lo = 0;
  86                     hi = DICT_nodir(p)-1;
  87                     indxp = (short*) ((char*) p+DICT_bsize(p)-sizeof(short));
  88                     continue;
  89                 }
  90             }
  91         }
  92         if (cmp < 0)
  93             lo = mid+1;
  94         else
  95             hi = mid-1;
  96     }
  97     return NULL;
  98 }
  99
 100 char *dict_lookup(Dict dict, const char *p)
 101 {
 102     dict->no_lookup++;
 103     if (!dict->head.root)
 104         return NULL;
 105     return dict_look(dict, (const Dict_char *) p, dict->head.root);
 106 }
 107 /*
 108  * Local variables:
 109  * c-basic-offset: 4
 110  * c-file-style: "Stroustrup"
 111  * indent-tabs-mode: nil
 112  * End:
 113  * vim: shiftwidth=4 tabstop=8 expandtab
 114  */
 115