1 /* $Id: man_hash.c,v 1.29 2014/12/01 08:05:52 schwarze 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 #include "config.h" 18 19 #include <sys/types.h> 20 21 #include <assert.h> 22 #include <ctype.h> 23 #include <limits.h> 24 #include <string.h> 25 26 #include "man.h" 27 #include "libman.h" 28 29 #define HASH_DEPTH 6 30 31 #define HASH_ROW(x) do { \ 32 if (isupper((unsigned char)(x))) \ 33 (x) -= 65; \ 34 else \ 35 (x) -= 97; \ 36 (x) *= HASH_DEPTH; \ 37 } while (/* CONSTCOND */ 0) 38 39 /* 40 * Lookup table is indexed first by lower-case first letter (plus one 41 * for the period, which is stored in the last row), then by lower or 42 * uppercase second letter. Buckets correspond to the index of the 43 * macro (the integer value of the enum stored as a char to save a bit 44 * of space). 45 */ 46 static unsigned char table[26 * HASH_DEPTH]; 47 48 49 /* 50 * XXX - this hash has global scope, so if intended for use as a library 51 * with multiple callers, it will need re-invocation protection. 52 */ 53 void 54 man_hash_init(void) 55 { 56 int i, j, x; 57 58 memset(table, UCHAR_MAX, sizeof(table)); 59 60 assert(MAN_MAX < UCHAR_MAX); 61 62 for (i = 0; i < (int)MAN_MAX; i++) { 63 x = man_macronames[i][0]; 64 65 assert(isalpha((unsigned char)x)); 66 67 HASH_ROW(x); 68 69 for (j = 0; j < HASH_DEPTH; j++) 70 if (UCHAR_MAX == table[x + j]) { 71 table[x + j] = (unsigned char)i; 72 break; 73 } 74 75 assert(j < HASH_DEPTH); 76 } 77 } 78 79 enum mant 80 man_hash_find(const char *tmp) 81 { 82 int x, y, i; 83 enum mant tok; 84 85 if ('\0' == (x = tmp[0])) 86 return(MAN_MAX); 87 if ( ! (isalpha((unsigned char)x))) 88 return(MAN_MAX); 89 90 HASH_ROW(x); 91 92 for (i = 0; i < HASH_DEPTH; i++) { 93 if (UCHAR_MAX == (y = table[x + i])) 94 return(MAN_MAX); 95 96 tok = (enum mant)y; 97 if (0 == strcmp(tmp, man_macronames[tok])) 98 return(tok); 99 } 100 101 return(MAN_MAX); 102 } 103