1 /* $Id: man_hash.c,v 1.25 2011/07/24 18:15:14 kristaps Exp $ */ 2 /* 3 * Copyright (c) 2008, 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv> 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 <ctype.h> 25 #include <limits.h> 26 #include <stdlib.h> 27 #include <string.h> 28 29 #include "man.h" 30 #include "mandoc.h" 31 #include "libman.h" 32 33 #define HASH_DEPTH 6 34 35 #define HASH_ROW(x) do { \ 36 if (isupper((unsigned char)(x))) \ 37 (x) -= 65; \ 38 else \ 39 (x) -= 97; \ 40 (x) *= HASH_DEPTH; \ 41 } while (/* CONSTCOND */ 0) 42 43 /* 44 * Lookup table is indexed first by lower-case first letter (plus one 45 * for the period, which is stored in the last row), then by lower or 46 * uppercase second letter. Buckets correspond to the index of the 47 * macro (the integer value of the enum stored as a char to save a bit 48 * of space). 49 */ 50 static unsigned char table[26 * HASH_DEPTH]; 51 52 /* 53 * XXX - this hash has global scope, so if intended for use as a library 54 * with multiple callers, it will need re-invocation protection. 55 */ 56 void 57 man_hash_init(void) 58 { 59 int i, j, x; 60 61 memset(table, UCHAR_MAX, sizeof(table)); 62 63 assert(/* LINTED */ 64 MAN_MAX < UCHAR_MAX); 65 66 for (i = 0; i < (int)MAN_MAX; i++) { 67 x = man_macronames[i][0]; 68 69 assert(isalpha((unsigned char)x)); 70 71 HASH_ROW(x); 72 73 for (j = 0; j < HASH_DEPTH; j++) 74 if (UCHAR_MAX == table[x + j]) { 75 table[x + j] = (unsigned char)i; 76 break; 77 } 78 79 assert(j < HASH_DEPTH); 80 } 81 } 82 83 84 enum mant 85 man_hash_find(const char *tmp) 86 { 87 int x, y, i; 88 enum mant tok; 89 90 if ('\0' == (x = tmp[0])) 91 return(MAN_MAX); 92 if ( ! (isalpha((unsigned char)x))) 93 return(MAN_MAX); 94 95 HASH_ROW(x); 96 97 for (i = 0; i < HASH_DEPTH; i++) { 98 if (UCHAR_MAX == (y = table[x + i])) 99 return(MAN_MAX); 100 101 tok = (enum mant)y; 102 if (0 == strcmp(tmp, man_macronames[tok])) 103 return(tok); 104 } 105 106 return(MAN_MAX); 107 } 108