| 1 | /* hash.c |
| 2 | * |
| 3 | * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002, |
| 4 | * 2005 by Larry Wall and others |
| 5 | * |
| 6 | * You may distribute under the terms of either the GNU General Public |
| 7 | * License or the Artistic License, as specified in the README file. |
| 8 | */ |
| 9 | |
| 10 | #include <stdio.h> |
| 11 | #include "EXTERN.h" |
| 12 | #include "a2p.h" |
| 13 | #include "util.h" |
| 14 | |
| 15 | #ifdef NETWARE |
| 16 | char *savestr(char *str); |
| 17 | #endif |
| 18 | |
| 19 | STR * |
| 20 | hfetch(register HASH *tb, char *key) |
| 21 | { |
| 22 | register char *s; |
| 23 | register int i; |
| 24 | register int hash; |
| 25 | register HENT *entry; |
| 26 | |
| 27 | if (!tb) |
| 28 | return Nullstr; |
| 29 | for (s=key, i=0, hash = 0; |
| 30 | /* while */ *s; |
| 31 | s++, i++, hash *= 5) { |
| 32 | hash += *s * coeff[i]; |
| 33 | } |
| 34 | entry = tb->tbl_array[hash & tb->tbl_max]; |
| 35 | for (; entry; entry = entry->hent_next) { |
| 36 | if (entry->hent_hash != hash) /* strings can't be equal */ |
| 37 | continue; |
| 38 | if (strNE(entry->hent_key,key)) /* is this it? */ |
| 39 | continue; |
| 40 | return entry->hent_val; |
| 41 | } |
| 42 | return Nullstr; |
| 43 | } |
| 44 | |
| 45 | bool |
| 46 | hstore(register HASH *tb, char *key, STR *val) |
| 47 | { |
| 48 | register char *s; |
| 49 | register int i; |
| 50 | register int hash; |
| 51 | register HENT *entry; |
| 52 | register HENT **oentry; |
| 53 | |
| 54 | if (!tb) |
| 55 | return FALSE; |
| 56 | for (s=key, i=0, hash = 0; |
| 57 | /* while */ *s; |
| 58 | s++, i++, hash *= 5) { |
| 59 | hash += *s * coeff[i]; |
| 60 | } |
| 61 | |
| 62 | oentry = &(tb->tbl_array[hash & tb->tbl_max]); |
| 63 | i = 1; |
| 64 | |
| 65 | for (entry = *oentry; entry; i=0, entry = entry->hent_next) { |
| 66 | if (entry->hent_hash != hash) /* strings can't be equal */ |
| 67 | continue; |
| 68 | if (strNE(entry->hent_key,key)) /* is this it? */ |
| 69 | continue; |
| 70 | /*NOSTRICT*/ |
| 71 | safefree(entry->hent_val); |
| 72 | entry->hent_val = val; |
| 73 | return TRUE; |
| 74 | } |
| 75 | /*NOSTRICT*/ |
| 76 | entry = (HENT*) safemalloc(sizeof(HENT)); |
| 77 | |
| 78 | entry->hent_key = savestr(key); |
| 79 | entry->hent_val = val; |
| 80 | entry->hent_hash = hash; |
| 81 | entry->hent_next = *oentry; |
| 82 | *oentry = entry; |
| 83 | |
| 84 | if (i) { /* initial entry? */ |
| 85 | tb->tbl_fill++; |
| 86 | if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) |
| 87 | hsplit(tb); |
| 88 | } |
| 89 | |
| 90 | return FALSE; |
| 91 | } |
| 92 | |
| 93 | void |
| 94 | hsplit(HASH *tb) |
| 95 | { |
| 96 | const int oldsize = tb->tbl_max + 1; |
| 97 | register int newsize = oldsize * 2; |
| 98 | register int i; |
| 99 | register HENT **a; |
| 100 | register HENT **b; |
| 101 | register HENT *entry; |
| 102 | register HENT **oentry; |
| 103 | |
| 104 | a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); |
| 105 | memset(&a[oldsize], 0, oldsize * sizeof(HENT*)); /* zero second half */ |
| 106 | tb->tbl_max = --newsize; |
| 107 | tb->tbl_array = a; |
| 108 | |
| 109 | for (i=0; i<oldsize; i++,a++) { |
| 110 | if (!*a) /* non-existent */ |
| 111 | continue; |
| 112 | b = a+oldsize; |
| 113 | for (oentry = a, entry = *a; entry; entry = *oentry) { |
| 114 | if ((entry->hent_hash & newsize) != i) { |
| 115 | *oentry = entry->hent_next; |
| 116 | entry->hent_next = *b; |
| 117 | if (!*b) |
| 118 | tb->tbl_fill++; |
| 119 | *b = entry; |
| 120 | continue; |
| 121 | } |
| 122 | else |
| 123 | oentry = &entry->hent_next; |
| 124 | } |
| 125 | if (!*a) /* everything moved */ |
| 126 | tb->tbl_fill--; |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | HASH * |
| 131 | hnew(void) |
| 132 | { |
| 133 | register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); |
| 134 | |
| 135 | tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); |
| 136 | tb->tbl_fill = 0; |
| 137 | tb->tbl_max = 7; |
| 138 | hiterinit(tb); /* so each() will start off right */ |
| 139 | memset(tb->tbl_array, 0, 8 * sizeof(HENT*)); |
| 140 | return tb; |
| 141 | } |
| 142 | |
| 143 | int |
| 144 | hiterinit(register HASH *tb) |
| 145 | { |
| 146 | tb->tbl_riter = -1; |
| 147 | tb->tbl_eiter = Null(HENT*); |
| 148 | return tb->tbl_fill; |
| 149 | } |