man_hash.c

   1 /*      $Id: man_hash.c,v 1.16 2010/01/01 17:14:28 kristaps Exp $ */
   2 /*
   3  * Copyright (c) 2008, 2009 Kristaps Dzonsons <kristaps@kth.se>
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17 #ifdef HAVE_CONFIG_H
  18 #include "config.h"
  19 #endif
  20
  21 #include <sys/types.h>
  22
  23 #include <assert.h>
  24 #include <limits.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include "libman.h"
  29
  30 static  u_char          table[26 * 6];
  31
  32 /*
  33  * XXX - this hash has global scope, so if intended for use as a library
  34  * with multiple callers, it will need re-invocation protection.
  35  */
  36 void
  37 man_hash_init(void)
  38 {
  39         int              i, j, x;
  40
  41         memset(table, UCHAR_MAX, sizeof(table));
  42
  43         for (i = 0; i < MAN_MAX; i++) {
  44                 x = man_macronames[i][0];
  45                 assert((x >= 65 && x <= 90) ||
  46                                 (x >= 97 && x <= 122));
  47
  48                 x -= (x <= 90) ? 65 : 97;
  49                 x *= 6;
  50
  51                 for (j = 0; j < 6; j++)
  52                         if (UCHAR_MAX == table[x + j]) {
  53                                 table[x + j] = (u_char)i;
  54                                 break;
  55                         }
  56                 assert(j < 6);
  57         }
  58 }
  59
  60 int
  61 man_hash_find(const char *tmp)
  62 {
  63         int              x, i, tok;
  64
  65         if (0 == (x = tmp[0]))
  66                 return(MAN_MAX);
  67         if ( ! ((x >= 65 && x <= 90) || (x >= 97 && x <= 122)))
  68                 return(MAN_MAX);
  69
  70         x -= (x <= 90) ? 65 : 97;
  71         x *= 6;
  72
  73         for (i = 0; i < 6; i++) {
  74                 if (UCHAR_MAX == (tok = table[x + i]))
  75                         return(MAN_MAX);
  76                 if (0 == strcmp(tmp, man_macronames[tok]))
  77                         return(tok);
  78         }
  79
  80         return(MAN_MAX);
  81 }