libguile/hash.c

   1 /*      Copyright (C) 1995,1996, 1997 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41 \f
  42
  43 #include <stdio.h>
  44 #include "_scm.h"
  45 #include "chars.h"
  46
  47 #include "hash.h"
  48 \f
  49
  50 #ifndef floor
  51 extern double floor();
  52 #endif
  53
  54
  55 unsigned long
  56 scm_hasher(obj, n, d)
  57      SCM obj;
  58      unsigned long n;
  59      scm_sizet d;
  60 {
  61   switch (7 & (int) obj) {
  62   case 2: case 6:               /* SCM_INUMP(obj) */
  63     return SCM_INUM(obj) % n;
  64   case 4:
  65     if SCM_ICHRP(obj)
  66       return (unsigned)(scm_downcase(SCM_ICHR(obj))) % n;
  67     switch ((int) obj) {
  68 #ifndef SICP
  69     case (int) SCM_EOL: d = 256; break;
  70 #endif
  71     case (int) SCM_BOOL_T: d = 257; break;
  72     case (int) SCM_BOOL_F: d = 258; break;
  73     case (int) SCM_EOF_VAL: d = 259; break;
  74     default: d = 263;           /* perhaps should be error */
  75     }
  76     return d % n;
  77   default: return 263 % n;      /* perhaps should be error */
  78   case 0:
  79     switch SCM_TYP7(obj) {
  80     default: return 263 % n;
  81     case scm_tc7_smob:
  82       switch SCM_TYP16(obj) {
  83       case scm_tcs_bignums:
  84       bighash: return SCM_INUM(scm_modulo(obj, SCM_MAKINUM(n)));
  85       default: return 263 % n;
  86 #ifdef SCM_FLOATS
  87       case scm_tc16_flo:
  88         if SCM_REALP(obj) {
  89           double r = SCM_REALPART(obj);
  90           if (floor(r)==r) {
  91             obj = scm_inexact_to_exact (obj);
  92             if SCM_IMP(obj) return SCM_INUM(obj) % n;
  93             goto bighash;
  94           }
  95         }
  96         obj = scm_number_to_string(obj, SCM_MAKINUM(10));
  97 #endif
  98       }
  99     case scm_tcs_symbols:
 100     case scm_tc7_string:
 101     case scm_tc7_substring:
 102       return scm_strhash(SCM_ROUCHARS(obj), (scm_sizet) SCM_ROLENGTH(obj), n);
 103     case scm_tc7_wvect:
 104     case scm_tc7_vector:
 105       {
 106         scm_sizet len = SCM_LENGTH(obj);
 107         SCM *data = SCM_VELTS(obj);
 108         if (len>5)
 109           {
 110             scm_sizet i = d/2;
 111             unsigned long h = 1;
 112             while (i--) h = ((h<<8) + (scm_hasher(data[h % len], n, 2))) % n;
 113             return h;
 114           }
 115         else
 116           {
 117             scm_sizet i = len;
 118             unsigned long h = (n)-1;
 119             while (i--) h = ((h<<8) + (scm_hasher(data[i], n, d/len))) % n;
 120             return h;
 121           }
 122       }
 123     case scm_tcs_cons_imcar: case scm_tcs_cons_nimcar:
 124       if (d) return (scm_hasher(SCM_CAR(obj), n, d/2)+scm_hasher(SCM_CDR(obj), n, d/2)) % n;
 125       else return 1;
 126     case scm_tc7_port:
 127       return ((SCM_RDNG & SCM_CAR(obj)) ? 260 : 261) % n;
 128     case scm_tcs_closures: case scm_tc7_contin: case scm_tcs_subrs:
 129       return 262 % n;
 130     }
 131   }
 132 }
 133
 134
 135 \f
 136
 137
 138 unsigned int
 139 scm_ihashq (obj, n)
 140      SCM obj;
 141      unsigned int n;
 142 {
 143   return (((unsigned int) obj) >> 1) % n;
 144 }
 145
 146
 147 SCM_PROC(s_hashq, "hashq", 2, 0, 0, scm_hashq);
 148
 149 SCM
 150 scm_hashq(obj, n)
 151      SCM obj;
 152      SCM n;
 153 {
 154   SCM_ASSERT(SCM_INUMP(n) && 0 <= n, n, SCM_ARG2, s_hashq);
 155   return SCM_MAKINUM(scm_ihashq (obj, SCM_INUM (n)));
 156 }
 157
 158
 159 \f
 160
 161
 162 unsigned int
 163 scm_ihashv (obj, n)
 164      SCM obj;
 165      unsigned int n;
 166 {
 167   if (SCM_ICHRP(obj))
 168     return ((unsigned int)(scm_downcase(SCM_ICHR(obj)))) % n; /* downcase!?!! */
 169
 170   if (SCM_NIMP(obj) && SCM_NUMP(obj))
 171     return (unsigned int) scm_hasher(obj, n, 10);
 172   else
 173     return ((unsigned int)obj) % n;
 174 }
 175
 176
 177 SCM_PROC(s_hashv, "hashv", 2, 0, 0, scm_hashv);
 178
 179 SCM
 180 scm_hashv(obj, n)
 181      SCM obj;
 182      SCM n;
 183 {
 184   SCM_ASSERT(SCM_INUMP(n) && 0 <= n, n, SCM_ARG2, s_hashv);
 185   return SCM_MAKINUM(scm_ihashv (obj, SCM_INUM (n)));
 186 }
 187
 188
 189 \f
 190
 191
 192 unsigned int
 193 scm_ihash (obj, n)
 194      SCM obj;
 195      unsigned int n;
 196 {
 197   return (unsigned int)scm_hasher (obj, n, 10);
 198 }
 199
 200 SCM_PROC(s_hash, "hash", 2, 0, 0, scm_hash);
 201
 202 SCM
 203 scm_hash(obj, n)
 204      SCM obj;
 205      SCM n;
 206 {
 207   SCM_ASSERT(SCM_INUMP(n) && 0 <= n, n, SCM_ARG2, s_hash);
 208   return SCM_MAKINUM(scm_ihash(obj, SCM_INUM(n)));
 209 }
 210
 211
 212 \f
 213
 214
 215 void
 216 scm_init_hash ()
 217 {
 218 #include "hash.x"
 219 }
 220