libguile/hash.c

   1 /*      Copyright (C) 1995,1996 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, 675 Mass Ave, Cambridge, MA 02139, USA.
  16  *
  17  * As a special exception, the Free Software Foundation gives permission
  18  * for additional uses of the text contained in its release of GUILE.
  19  *
  20  * The exception is that, if you link the GUILE library with other files
  21  * to produce an executable, this does not by itself cause the
  22  * resulting executable to be covered by the GNU General Public License.
  23  * Your use of that executable is in no way restricted on account of
  24  * linking the GUILE library code into it.
  25  *
  26  * This exception does not however invalidate any other reasons why
  27  * the executable file might be covered by the GNU General Public License.
  28  *
  29  * This exception applies only to the code released by the
  30  * Free Software Foundation under the name GUILE.  If you copy
  31  * code from other Free Software Foundation releases into a copy of
  32  * GUILE, as the General Public License permits, the exception does
  33  * not apply to the code that you add in this way.  To avoid misleading
  34  * anyone as to the status of such modified files, you must delete
  35  * this exception notice from them.
  36  *
  37  * If you write modifications of your own for GUILE, it is your choice
  38  * whether to permit this exception to apply to your modifications.
  39  * If you do not wish that, delete this exception notice.
  40  */
  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 #ifdef __STDC__
  55 unsigned long
  56 scm_hasher(SCM obj, unsigned long n, scm_sizet d)
  57 #else
  58 unsigned long
  59 scm_hasher(obj, n, d)
  60      SCM obj;
  61      unsigned long n;
  62      scm_sizet d;
  63 #endif
  64 {
  65   switch (7 & (int) obj) {
  66   case 2: case 6:               /* SCM_INUMP(obj) */
  67     return SCM_INUM(obj) % n;
  68   case 4:
  69     if SCM_ICHRP(obj)
  70       return (unsigned)(scm_downcase(SCM_ICHR(obj))) % n;
  71     switch ((int) obj) {
  72 #ifndef SICP
  73     case (int) SCM_EOL: d = 256; break;
  74 #endif
  75     case (int) SCM_BOOL_T: d = 257; break;
  76     case (int) SCM_BOOL_F: d = 258; break;
  77     case (int) SCM_EOF_VAL: d = 259; break;
  78     default: d = 263;           /* perhaps should be error */
  79     }
  80     return d % n;
  81   default: return 263 % n;      /* perhaps should be error */
  82   case 0:
  83     switch SCM_TYP7(obj) {
  84     default: return 263 % n;
  85     case scm_tc7_smob:
  86       switch SCM_TYP16(obj) {
  87       case scm_tcs_bignums:
  88       bighash: return SCM_INUM(scm_modulo(obj, SCM_MAKINUM(n)));
  89       default: return 263 % n;
  90 #ifdef SCM_FLOATS
  91       case scm_tc16_flo:
  92         if SCM_REALP(obj) {
  93           double r = SCM_REALPART(obj);
  94           if (floor(r)==r) {
  95             obj = scm_inexact_to_exact (obj);
  96             if SCM_IMP(obj) return SCM_INUM(obj) % n;
  97             goto bighash;
  98           }
  99         }
 100         obj = scm_number_to_string(obj, SCM_MAKINUM(10));
 101 #endif
 102       }
 103     case scm_tcs_symbols:
 104     case scm_tc7_string:
 105     case scm_tc7_mb_string:
 106     case scm_tc7_substring:
 107     case scm_tc7_mb_substring:
 108       return scm_strhash(SCM_ROUCHARS(obj), (scm_sizet) SCM_ROLENGTH(obj), n);
 109     case scm_tc7_wvect:
 110     case scm_tc7_vector:
 111       {
 112         scm_sizet len = SCM_LENGTH(obj);
 113         SCM *data = SCM_VELTS(obj);
 114         if (len>5)
 115           {
 116             scm_sizet i = d/2;
 117             unsigned long h = 1;
 118             while (i--) h = ((h<<8) + (scm_hasher(data[h % len], n, 2))) % n;
 119             return h;
 120           }
 121         else
 122           {
 123             scm_sizet i = len;
 124             unsigned long h = (n)-1;
 125             while (i--) h = ((h<<8) + (scm_hasher(data[i], n, d/len))) % n;
 126             return h;
 127           }
 128       }
 129     case scm_tcs_cons_imcar: case scm_tcs_cons_nimcar:
 130       if (d) return (scm_hasher(SCM_CAR(obj), n, d/2)+scm_hasher(SCM_CDR(obj), n, d/2)) % n;
 131       else return 1;
 132     case scm_tc7_port:
 133       return ((SCM_RDNG & SCM_CAR(obj)) ? 260 : 261) % n;
 134     case scm_tcs_closures: case scm_tc7_contin: case scm_tcs_subrs:
 135       return 262 % n;
 136     }
 137   }
 138 }
 139
 140
 141 \f
 142
 143 #ifdef __STDC__
 144 unsigned int
 145 scm_ihashq (SCM obj, unsigned int n)
 146 #else
 147 unsigned int
 148 scm_ihashq (obj, n)
 149      SCM obj;
 150      unsigned int n;
 151 #endif
 152 {
 153   return (((unsigned int) obj) >> 1) % n;
 154 }
 155
 156
 157 SCM_PROC(s_hashq, "hashq", 2, 0, 0, scm_hashq);
 158 #ifdef __STDC__
 159 SCM
 160 scm_hashq(SCM obj, SCM n)
 161 #else
 162 SCM
 163 scm_hashq(obj, n)
 164      SCM obj;
 165      SCM n;
 166 #endif
 167 {
 168   SCM_ASSERT(SCM_INUMP(n) && 0 <= n, n, SCM_ARG2, s_hashq);
 169   return SCM_MAKINUM(scm_ihashq (obj, SCM_INUM (n)));
 170 }
 171
 172
 173 \f
 174
 175 #ifdef __STDC__
 176 unsigned int
 177 scm_ihashv (SCM obj, unsigned int n)
 178 #else
 179 unsigned int
 180 scm_ihashv (obj, n)
 181      SCM obj;
 182      unsigned int n;
 183 #endif
 184 {
 185   if (SCM_ICHRP(obj))
 186     return ((unsigned int)(scm_downcase(SCM_ICHR(obj)))) % n; /* downcase!?!! */
 187
 188   if (SCM_NIMP(obj) && SCM_NUMP(obj))
 189     return (unsigned int) scm_hasher(obj, n, 10);
 190   else
 191     return ((unsigned int)obj) % n;
 192 }
 193
 194
 195 SCM_PROC(s_hashv, "hashv", 2, 0, 0, scm_hashv);
 196 #ifdef __STDC__
 197 SCM
 198 scm_hashv(SCM obj, SCM n)
 199 #else
 200 SCM
 201 scm_hashv(obj, n)
 202      SCM obj;
 203      SCM n;
 204 #endif
 205 {
 206   SCM_ASSERT(SCM_INUMP(n) && 0 <= n, n, SCM_ARG2, s_hashv);
 207   return SCM_MAKINUM(scm_ihashv (obj, SCM_INUM (n)));
 208 }
 209
 210
 211 \f
 212
 213 #ifdef __STDC__
 214 unsigned int
 215 scm_ihash (SCM obj, unsigned int n)
 216 #else
 217 unsigned int
 218 scm_ihash (obj, n)
 219      SCM obj;
 220      unsigned int n;
 221 #endif
 222 {
 223   return (unsigned int)scm_hasher (obj, n, 10);
 224 }
 225
 226 SCM_PROC(s_hash, "hash", 2, 0, 0, scm_hash);
 227 #ifdef __STDC__
 228 SCM
 229 scm_hash(SCM obj, SCM n)
 230 #else
 231 SCM
 232 scm_hash(obj, n)
 233      SCM obj;
 234      SCM n;
 235 #endif
 236 {
 237   SCM_ASSERT(SCM_INUMP(n) && 0 <= n, n, SCM_ARG2, s_hash);
 238   return SCM_MAKINUM(scm_ihash(obj, SCM_INUM(n)));
 239 }
 240
 241
 242 \f
 243
 244 #ifdef __STDC__
 245 void
 246 scm_init_hash (void)
 247 #else
 248 void
 249 scm_init_hash ()
 250 #endif
 251 {
 252 #include "hash.x"
 253 }
 254