usr/src/cmd/mandoc/man_hash.c

   1 /*      $Id: man_hash.c,v 1.34 2015/10/06 18:32:19 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2008, 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>
   4  * Copyright (c) 2015 Ingo Schwarze <schwarze@openbsd.org>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include "config.h"
  19
  20 #include <sys/types.h>
  21
  22 #include <assert.h>
  23 #include <ctype.h>
  24 #include <limits.h>
  25 #include <string.h>
  26
  27 #include "roff.h"
  28 #include "man.h"
  29 #include "libman.h"
  30
  31 #define HASH_DEPTH       6
  32
  33 #define HASH_ROW(x) do { \
  34                 if (isupper((unsigned char)(x))) \
  35                         (x) -= 65; \
  36                 else \
  37                         (x) -= 97; \
  38                 (x) *= HASH_DEPTH; \
  39         } while (/* CONSTCOND */ 0)
  40
  41 /*
  42  * Lookup table is indexed first by lower-case first letter (plus one
  43  * for the period, which is stored in the last row), then by lower or
  44  * uppercase second letter.  Buckets correspond to the index of the
  45  * macro (the integer value of the enum stored as a char to save a bit
  46  * of space).
  47  */
  48 static  unsigned char    table[26 * HASH_DEPTH];
  49
  50
  51 void
  52 man_hash_init(void)
  53 {
  54         int              i, j, x;
  55
  56         if (*table != '\0')
  57                 return;
  58
  59         memset(table, UCHAR_MAX, sizeof(table));
  60
  61         for (i = 0; i < (int)MAN_MAX; i++) {
  62                 x = man_macronames[i][0];
  63
  64                 assert(isalpha((unsigned char)x));
  65
  66                 HASH_ROW(x);
  67
  68                 for (j = 0; j < HASH_DEPTH; j++)
  69                         if (UCHAR_MAX == table[x + j]) {
  70                                 table[x + j] = (unsigned char)i;
  71                                 break;
  72                         }
  73
  74                 assert(j < HASH_DEPTH);
  75         }
  76 }
  77
  78 int
  79 man_hash_find(const char *tmp)
  80 {
  81         int              x, y, i;
  82         int              tok;
  83
  84         if ('\0' == (x = tmp[0]))
  85                 return TOKEN_NONE;
  86         if ( ! (isalpha((unsigned char)x)))
  87                 return TOKEN_NONE;
  88
  89         HASH_ROW(x);
  90
  91         for (i = 0; i < HASH_DEPTH; i++) {
  92                 if (UCHAR_MAX == (y = table[x + i]))
  93                         return TOKEN_NONE;
  94
  95                 tok = y;
  96                 if (0 == strcmp(tmp, man_macronames[tok]))
  97                         return tok;
  98         }
  99
 100         return TOKEN_NONE;
 101 }