man_hash.c

   1 /*      $Id: man_hash.c,v 1.15 2009/09/23 11:53:45 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 #include <sys/types.h>
  18
  19 #include <assert.h>
  20 #include <limits.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24 #include "libman.h"
  25
  26 static  u_char          table[26 * 6];
  27
  28 /*
  29  * XXX - this hash has global scope, so if intended for use as a library
  30  * with multiple callers, it will need re-invocation protection.
  31  */
  32 void
  33 man_hash_init(void)
  34 {
  35         int              i, j, x;
  36
  37         memset(table, UCHAR_MAX, sizeof(table));
  38
  39         for (i = 0; i < MAN_MAX; i++) {
  40                 x = man_macronames[i][0];
  41                 assert((x >= 65 && x <= 90) ||
  42                                 (x >= 97 && x <= 122));
  43
  44                 x -= (x <= 90) ? 65 : 97;
  45                 x *= 6;
  46
  47                 for (j = 0; j < 6; j++)
  48                         if (UCHAR_MAX == table[x + j]) {
  49                                 table[x + j] = (u_char)i;
  50                                 break;
  51                         }
  52                 assert(j < 6);
  53         }
  54 }
  55
  56 int
  57 man_hash_find(const char *tmp)
  58 {
  59         int              x, i, tok;
  60
  61         if (0 == (x = tmp[0]))
  62                 return(MAN_MAX);
  63         if ( ! ((x >= 65 && x <= 90) || (x >= 97 && x <= 122)))
  64                 return(MAN_MAX);
  65
  66         x -= (x <= 90) ? 65 : 97;
  67         x *= 6;
  68
  69         for (i = 0; i < 6; i++) {
  70                 if (UCHAR_MAX == (tok = table[x + i]))
  71                         return(MAN_MAX);
  72                 if (0 == strcmp(tmp, man_macronames[tok]))
  73                         return(tok);
  74         }
  75
  76         return(MAN_MAX);
  77 }