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428
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1 /* Hash tables.
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2 Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
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2515
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3 Copyright (C) 2003, 2004 Ben Wing.
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428
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4
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5 This file is part of XEmacs.
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6
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7 XEmacs is free software; you can redistribute it and/or modify it
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8 under the terms of the GNU General Public License as published by the
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9 Free Software Foundation; either version 2, or (at your option) any
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10 later version.
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11
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12 XEmacs is distributed in the hope that it will be useful, but WITHOUT
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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15 for more details.
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16
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17 You should have received a copy of the GNU General Public License
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18 along with XEmacs; see the file COPYING. If not, write to
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19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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20 Boston, MA 02111-1307, USA. */
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21
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22 /* Synched up with: Not in FSF. */
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23
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1292
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24 /* Author: Lost in the mists of history. At least back to Lucid 19.3,
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25 circa Sep 1992. */
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26
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428
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27 #include <config.h>
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28 #include "lisp.h"
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29 #include "hash.h"
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30
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1204
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31 #define NULL_ENTRY ((void *) 0xdeadbeef) /* -559038737 base 10 */
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428
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32
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33 #define COMFORTABLE_SIZE(size) (21 * (size) / 16)
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34
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3025
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35 #define KEYS_DIFFER_P(old, new_, testfun) \
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36 (((old) != (new_)) && (!(testfun) || !(testfun) ((old),(new_))))
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428
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37
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665
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38 static void rehash (hentry *harray, struct hash_table *ht, Elemcount size);
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428
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39
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665
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40 Hashcode
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41 memory_hash (const void *xv, Bytecount size)
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428
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42 {
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665
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43 Hashcode h = 0;
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442
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44 unsigned const char *x = (unsigned const char *) xv;
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428
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45
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46 if (!x) return 0;
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47
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48 while (size--)
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49 {
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665
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50 Hashcode g;
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428
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51 h = (h << 4) + *x++;
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52 if ((g = h & 0xf0000000) != 0)
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53 h = (h ^ (g >> 24)) ^ g;
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54 }
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55
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56 return h;
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57 }
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58
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2515
|
59 static int
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60 string_equal (const void *st1, const void *st2)
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61 {
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62 if (!st1)
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63 return st2 ? 0 : 1;
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64 else if (!st2)
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65 return 0;
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66 else
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67 return !strcmp ((const char *) st1, (const char *) st2);
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68 }
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69
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70 static Hashcode
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71 string_hash (const void *xv)
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442
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72 {
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665
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73 Hashcode h = 0;
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442
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74 unsigned const char *x = (unsigned const char *) xv;
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75
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76 if (!x) return 0;
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77
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78 while (*x)
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79 {
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665
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80 Hashcode g;
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442
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81 h = (h << 4) + *x++;
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82 if ((g = h & 0xf0000000) != 0)
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83 h = (h ^ (g >> 24)) ^ g;
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84 }
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85
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86 return h;
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87 }
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88
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428
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89 /* Return a suitable size for a hash table, with at least SIZE slots. */
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665
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90 static Elemcount
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91 hash_table_size (Elemcount requested_size)
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428
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92 {
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93 /* Return some prime near, but greater than or equal to, SIZE.
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94 Decades from the time of writing, someone will have a system large
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95 enough that the list below will be too short... */
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665
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96 static const Elemcount primes [] =
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428
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97 {
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98 19, 29, 41, 59, 79, 107, 149, 197, 263, 347, 457, 599, 787, 1031,
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99 1361, 1777, 2333, 3037, 3967, 5167, 6719, 8737, 11369, 14783,
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100 19219, 24989, 32491, 42257, 54941, 71429, 92861, 120721, 156941,
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101 204047, 265271, 344857, 448321, 582821, 757693, 985003, 1280519,
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102 1664681, 2164111, 2813353, 3657361, 4754591, 6180989, 8035301,
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103 10445899, 13579681, 17653589, 22949669, 29834603, 38784989,
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104 50420551, 65546729, 85210757, 110774011, 144006217, 187208107,
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105 243370577, 316381771, 411296309, 534685237, 695090819, 903618083,
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647
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106 1174703521, 1527114613, 1985248999 /* , 2580823717UL, 3355070839UL */
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428
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107 };
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108 /* We've heard of binary search. */
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109 int low, high;
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110 for (low = 0, high = countof (primes) - 1; high - low > 1;)
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111 {
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112 /* Loop Invariant: size < primes [high] */
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113 int mid = (low + high) / 2;
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114 if (primes [mid] < requested_size)
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115 low = mid;
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116 else
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117 high = mid;
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118 }
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119 return primes [high];
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120 }
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121
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442
|
122 const void *
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123 gethash (const void *key, struct hash_table *hash_table, const void **ret_value)
|
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428
|
124 {
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125 if (!key)
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126 {
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127 *ret_value = hash_table->zero_entry;
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128 return (void *) hash_table->zero_set;
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129 }
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130 else
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131 {
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132 hentry *harray = hash_table->harray;
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133 hash_table_test_function test_function = hash_table->test_function;
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665
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134 Elemcount size = hash_table->size;
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135 Hashcode hcode_initial =
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428
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136 hash_table->hash_function ?
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137 hash_table->hash_function (key) :
|
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665
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138 (Hashcode) key;
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139 Elemcount hcode = (Elemcount) (hcode_initial % size);
|
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428
|
140 hentry *e = &harray [hcode];
|
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442
|
141 const void *e_key = e->key;
|
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428
|
142
|
|
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143 if (e_key ?
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144 KEYS_DIFFER_P (e_key, key, test_function) :
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145 e->contents == NULL_ENTRY)
|
|
|
146 {
|
|
665
|
147 Elemcount h2 = size - 2;
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|
|
148 Elemcount incr = (Elemcount) (1 + (hcode_initial % h2));
|
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428
|
149 do
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|
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150 {
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151 hcode += incr; if (hcode >= size) hcode -= size;
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152 e = &harray [hcode];
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153 e_key = e->key;
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154 }
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155 while (e_key ?
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156 KEYS_DIFFER_P (e_key, key, test_function) :
|
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|
157 e->contents == NULL_ENTRY);
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|
|
158 }
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159
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|
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160 *ret_value = e->contents;
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161 return e->key;
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|
162 }
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|
163 }
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164
|
|
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165 void
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166 clrhash (struct hash_table *hash_table)
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|
|
167 {
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|
|
168 memset (hash_table->harray, 0, sizeof (hentry) * hash_table->size);
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|
|
169 hash_table->zero_entry = 0;
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170 hash_table->zero_set = 0;
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171 hash_table->fullness = 0;
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|
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172 }
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|
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173
|
|
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174 void
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|
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175 free_hash_table (struct hash_table *hash_table)
|
|
|
176 {
|
|
1726
|
177 xfree (hash_table->harray, hentry *);
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|
|
178 xfree (hash_table, struct hash_table *);
|
|
428
|
179 }
|
|
|
180
|
|
2515
|
181 struct hash_table *
|
|
665
|
182 make_hash_table (Elemcount size)
|
|
428
|
183 {
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|
|
184 struct hash_table *hash_table = xnew_and_zero (struct hash_table);
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|
|
185 hash_table->size = hash_table_size (COMFORTABLE_SIZE (size));
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|
|
186 hash_table->harray = xnew_array (hentry, hash_table->size);
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|
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187 clrhash (hash_table);
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|
|
188 return hash_table;
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|
|
189 }
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|
|
190
|
|
|
191 struct hash_table *
|
|
2515
|
192 make_string_hash_table (Elemcount size)
|
|
|
193 {
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|
|
194 return make_general_hash_table (size, string_hash, string_equal);
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|
|
195 }
|
|
|
196
|
|
|
197 struct hash_table *
|
|
665
|
198 make_general_hash_table (Elemcount size,
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|
428
|
199 hash_table_hash_function hash_function,
|
|
|
200 hash_table_test_function test_function)
|
|
|
201 {
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|
|
202 struct hash_table* hash_table = make_hash_table (size);
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|
|
203 hash_table->hash_function = hash_function;
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|
|
204 hash_table->test_function = test_function;
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|
|
205 return hash_table;
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|
|
206 }
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|
|
207
|
|
|
208 static void
|
|
665
|
209 grow_hash_table (struct hash_table *hash_table, Elemcount new_size)
|
|
428
|
210 {
|
|
665
|
211 Elemcount old_size = hash_table->size;
|
|
428
|
212 hentry *old_harray = hash_table->harray;
|
|
|
213
|
|
|
214 hash_table->size = hash_table_size (new_size);
|
|
|
215 hash_table->harray = xnew_array (hentry, hash_table->size);
|
|
|
216
|
|
|
217 /* do the rehash on the "grown" table */
|
|
|
218 {
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|
|
219 long old_zero_set = hash_table->zero_set;
|
|
|
220 void *old_zero_entry = hash_table->zero_entry;
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|
|
221 clrhash (hash_table);
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|
|
222 hash_table->zero_set = old_zero_set;
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|
|
223 hash_table->zero_entry = old_zero_entry;
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|
|
224 rehash (old_harray, hash_table, old_size);
|
|
|
225 }
|
|
|
226
|
|
1726
|
227 xfree (old_harray, hentry *);
|
|
428
|
228 }
|
|
|
229
|
|
|
230 void
|
|
1292
|
231 pregrow_hash_table_if_necessary (struct hash_table *hash_table,
|
|
|
232 Elemcount breathing_room)
|
|
|
233 {
|
|
|
234 Elemcount comfortable_size = COMFORTABLE_SIZE (hash_table->fullness);
|
|
|
235 if (hash_table->size < comfortable_size - breathing_room)
|
|
|
236 grow_hash_table (hash_table, comfortable_size + 1);
|
|
|
237 }
|
|
|
238
|
|
|
239 void
|
|
442
|
240 puthash (const void *key, void *contents, struct hash_table *hash_table)
|
|
428
|
241 {
|
|
|
242 if (!key)
|
|
|
243 {
|
|
|
244 hash_table->zero_entry = contents;
|
|
|
245 hash_table->zero_set = 1;
|
|
|
246 }
|
|
|
247 else
|
|
|
248 {
|
|
|
249 hash_table_test_function test_function = hash_table->test_function;
|
|
665
|
250 Elemcount size = hash_table->size;
|
|
428
|
251 hentry *harray = hash_table->harray;
|
|
665
|
252 Hashcode hcode_initial =
|
|
428
|
253 hash_table->hash_function ?
|
|
|
254 hash_table->hash_function (key) :
|
|
665
|
255 (Hashcode) key;
|
|
|
256 Elemcount hcode = (Elemcount) (hcode_initial % size);
|
|
|
257 Elemcount h2 = size - 2;
|
|
|
258 Elemcount incr = (Elemcount) (1 + (hcode_initial % h2));
|
|
442
|
259 const void *e_key = harray [hcode].key;
|
|
|
260 const void *oldcontents;
|
|
428
|
261
|
|
|
262 if (e_key && KEYS_DIFFER_P (e_key, key, test_function))
|
|
|
263 {
|
|
|
264 do
|
|
|
265 {
|
|
|
266 hcode += incr; if (hcode >= size) hcode -= size;
|
|
|
267 e_key = harray [hcode].key;
|
|
|
268 }
|
|
|
269 while (e_key && KEYS_DIFFER_P (e_key, key, test_function));
|
|
|
270 }
|
|
|
271 oldcontents = harray [hcode].contents;
|
|
|
272 harray [hcode].key = key;
|
|
|
273 harray [hcode].contents = contents;
|
|
|
274 /* If the entry that we used was a deleted entry,
|
|
|
275 check for a non deleted entry of the same key,
|
|
|
276 then delete it. */
|
|
|
277 if (!e_key && oldcontents == NULL_ENTRY)
|
|
|
278 {
|
|
|
279 hentry *e;
|
|
|
280
|
|
|
281 do
|
|
|
282 {
|
|
|
283 hcode += incr; if (hcode >= size) hcode -= size;
|
|
|
284 e = &harray [hcode];
|
|
|
285 e_key = e->key;
|
|
|
286 }
|
|
|
287 while (e_key ?
|
|
|
288 KEYS_DIFFER_P (e_key, key, test_function):
|
|
|
289 e->contents == NULL_ENTRY);
|
|
|
290
|
|
|
291 if (e_key)
|
|
|
292 {
|
|
|
293 e->key = 0;
|
|
|
294 e->contents = NULL_ENTRY;
|
|
|
295 }
|
|
|
296 }
|
|
|
297
|
|
|
298 /* only increment the fullness when we used up a new hentry */
|
|
|
299 if (!e_key || KEYS_DIFFER_P (e_key, key, test_function))
|
|
|
300 {
|
|
665
|
301 Elemcount comfortable_size = COMFORTABLE_SIZE (++(hash_table->fullness));
|
|
428
|
302 if (hash_table->size < comfortable_size)
|
|
|
303 grow_hash_table (hash_table, comfortable_size + 1);
|
|
|
304 }
|
|
|
305 }
|
|
|
306 }
|
|
|
307
|
|
|
308 static void
|
|
665
|
309 rehash (hentry *harray, struct hash_table *hash_table, Elemcount size)
|
|
428
|
310 {
|
|
|
311 hentry *limit = harray + size;
|
|
|
312 hentry *e;
|
|
|
313 for (e = harray; e < limit; e++)
|
|
|
314 {
|
|
|
315 if (e->key)
|
|
|
316 puthash (e->key, e->contents, hash_table);
|
|
|
317 }
|
|
|
318 }
|
|
|
319
|
|
|
320 void
|
|
442
|
321 remhash (const void *key, struct hash_table *hash_table)
|
|
428
|
322 {
|
|
|
323 if (!key)
|
|
|
324 {
|
|
|
325 hash_table->zero_entry = 0;
|
|
|
326 hash_table->zero_set = 0;
|
|
|
327 }
|
|
|
328 else
|
|
|
329 {
|
|
|
330 hentry *harray = hash_table->harray;
|
|
|
331 hash_table_test_function test_function = hash_table->test_function;
|
|
665
|
332 Elemcount size = hash_table->size;
|
|
|
333 Hashcode hcode_initial =
|
|
428
|
334 (hash_table->hash_function) ?
|
|
|
335 (hash_table->hash_function (key)) :
|
|
665
|
336 ((Hashcode) key);
|
|
|
337 Elemcount hcode = (Elemcount) (hcode_initial % size);
|
|
428
|
338 hentry *e = &harray [hcode];
|
|
442
|
339 const void *e_key = e->key;
|
|
428
|
340
|
|
|
341 if (e_key ?
|
|
|
342 KEYS_DIFFER_P (e_key, key, test_function) :
|
|
|
343 e->contents == NULL_ENTRY)
|
|
|
344 {
|
|
665
|
345 Elemcount h2 = size - 2;
|
|
|
346 Elemcount incr = (Elemcount) (1 + (hcode_initial % h2));
|
|
428
|
347 do
|
|
|
348 {
|
|
|
349 hcode += incr; if (hcode >= size) hcode -= size;
|
|
|
350 e = &harray [hcode];
|
|
|
351 e_key = e->key;
|
|
|
352 }
|
|
|
353 while (e_key?
|
|
|
354 KEYS_DIFFER_P (e_key, key, test_function):
|
|
|
355 e->contents == NULL_ENTRY);
|
|
|
356 }
|
|
|
357 if (e_key)
|
|
|
358 {
|
|
|
359 e->key = 0;
|
|
|
360 e->contents = NULL_ENTRY;
|
|
|
361 /* Note: you can't do fullness-- here, it breaks the world. */
|
|
|
362 }
|
|
|
363 }
|
|
|
364 }
|
|
|
365
|
|
|
366 void
|
|
|
367 maphash (maphash_function mf, struct hash_table *hash_table, void *arg)
|
|
|
368 {
|
|
|
369 hentry *e;
|
|
|
370 hentry *limit;
|
|
|
371
|
|
|
372 if (hash_table->zero_set)
|
|
|
373 {
|
|
|
374 if (mf (0, hash_table->zero_entry, arg))
|
|
|
375 return;
|
|
|
376 }
|
|
|
377
|
|
|
378 for (e = hash_table->harray, limit = e + hash_table->size; e < limit; e++)
|
|
|
379 {
|
|
|
380 if (e->key && mf (e->key, e->contents, arg))
|
|
|
381 return;
|
|
|
382 }
|
|
|
383 }
|
|
|
384
|
|
|
385 void
|
|
|
386 map_remhash (remhash_predicate predicate, struct hash_table *hash_table, void *arg)
|
|
|
387 {
|
|
|
388 hentry *e;
|
|
|
389 hentry *limit;
|
|
|
390
|
|
|
391 if (hash_table->zero_set && predicate (0, hash_table->zero_entry, arg))
|
|
|
392 {
|
|
|
393 hash_table->zero_set = 0;
|
|
|
394 hash_table->zero_entry = 0;
|
|
|
395 }
|
|
|
396
|
|
|
397 for (e = hash_table->harray, limit = e + hash_table->size; e < limit; e++)
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398 if (predicate (e->key, e->contents, arg))
|
|
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399 {
|
|
|
400 e->key = 0;
|
|
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401 e->contents = NULL_ENTRY;
|
|
|
402 }
|
|
|
403 }
|
