src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1987 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 1, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 /* Written by Howard Gayle.  See chartab.c for details. */
  21
  22 #include "config.h"
  23 #include "lisp.h"
  24 #include "buffer.h"
  25
  26 Lisp_Object Qcase_table_p;
  27 Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
  28 Lisp_Object Vascii_canon_table, Vascii_eqv_table;
  29
  30 void compute_trt_inverse ();
  31
  32 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
  33   "Return t iff ARG is a case table.\n\
  34 See `set-case-table' for more information on these data structures.")
  35   (table)
  36      Lisp_Object table;
  37 {
  38   Lisp_Object down, up, canon, eqv;
  39   down = Fcar_safe (table);
  40   up = Fcar_safe (Fcdr_safe (table));
  41   canon = Fcar_safe (Fcdr_safe (Fcdr_safe (table)));
  42   eqv = Fcar_safe (Fcdr_safe (Fcdr_safe (Fcdr_safe (table))));
  43
  44 #define STRING256_P(obj) \
  45   (XTYPE (obj) == Lisp_String && XSTRING (obj)->size == 256)
  46
  47   return (STRING256_P (down)
  48           && (NILP (up) || STRING256_P (up))
  49           && ((NILP (canon) && NILP (eqv))
  50               || (STRING256_P (canon) && STRING256_P (eqv)))
  51           ? Qt : Qnil);
  52 }
  53
  54 static Lisp_Object
  55 check_case_table (obj)
  56      Lisp_Object obj;
  57 {
  58   register Lisp_Object tem;
  59
  60   while (tem = Fcase_table_p (obj), NILP (tem))
  61     obj = wrong_type_argument (Qcase_table_p, obj);
  62   return (obj);
  63 }
  64
  65 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  66   "Return the case table of the current buffer.")
  67   ()
  68 {
  69   Lisp_Object down, up, canon, eqv;
  70
  71   down = current_buffer->downcase_table;
  72   up = current_buffer->upcase_table;
  73   canon = current_buffer->case_canon_table;
  74   eqv = current_buffer->case_eqv_table;
  75
  76   return Fcons (down, Fcons (up, Fcons (canon, Fcons (eqv, Qnil))));
  77 }
  78
  79 DEFUN ("standard-case-table", Fstandard_case_table,
  80   Sstandard_case_table, 0, 0, 0,
  81   "Return the standard case table.\n\
  82 This is the one used for new buffers.")
  83   ()
  84 {
  85   return Fcons (Vascii_downcase_table,
  86                 Fcons (Vascii_upcase_table,
  87                        Fcons (Vascii_canon_table,
  88                               Fcons (Vascii_eqv_table, Qnil))));
  89 }
  90
  91 static Lisp_Object set_case_table ();
  92
  93 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  94   "Select a new case table for the current buffer.\n\
  95 A case table is a list (DOWNCASE UPCASE CANONICALIZE EQUIVALENCES)\n\
  96  where each element is either nil or a string of length 256.\n\
  97 DOWNCASE maps each character to its lower-case equivalent.\n\
  98 UPCASE maps each character to its upper-case equivalent;\n\
  99  if lower and upper case characters are in 1-1 correspondence,\n\
 100  you may use nil and the upcase table will be deduced from DOWNCASE.\n\
 101 CANONICALIZE maps each character to a canonical equivalent;\n\
 102  any two characters that are related by case-conversion have the same\n\
 103  canonical equivalent character.\n\
 104 EQUIVALENCES is a map that cyclicly permutes each equivalence class\n\
 105  (of characters with the same canonical equivalent).\n\
 106 Both CANONICALIZE and EQUIVALENCES may be nil, in which case\n\
 107  both are deduced from DOWNCASE and UPCASE.")
 108   (table)
 109      Lisp_Object table;
 110 {
 111   return set_case_table (table, 0);
 112 }
 113
 114 DEFUN ("set-standard-case-table",
 115        Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
 116   "Select a new standard case table for new buffers.\n\
 117 See `set-case-table' for more info on case tables.")
 118   (table)
 119      Lisp_Object table;
 120 {
 121   return set_case_table (table, 1);
 122 }
 123
 124 static Lisp_Object
 125 set_case_table (table, standard)
 126      Lisp_Object table;
 127      int standard;
 128 {
 129   Lisp_Object down, up, canon, eqv;
 130
 131   check_case_table (table);
 132
 133   down = Fcar_safe (table);
 134   up = Fcar_safe (Fcdr_safe (table));
 135   canon = Fcar_safe (Fcdr_safe (Fcdr_safe (table)));
 136   eqv = Fcar_safe (Fcdr_safe (Fcdr_safe (Fcdr_safe (table))));
 137
 138   if (NILP (up))
 139     {
 140       up = Fmake_string (make_number (256), make_number (0));
 141       compute_trt_inverse (XSTRING (down)->data, XSTRING (up)->data);
 142     }
 143
 144   if (NILP (canon))
 145     {
 146       register int i;
 147       unsigned char *upvec = XSTRING (up)->data;
 148       unsigned char *downvec = XSTRING (down)->data;
 149
 150       canon = Fmake_string (make_number (256), make_number (0));
 151       eqv = Fmake_string (make_number (256), make_number (0));
 152
 153       /* Set up the CANON vector; for each character,
 154          this sequence of upcasing and downcasing ought to
 155          get the "preferred" lowercase equivalent.  */
 156       for (i = 0; i < 256; i++)
 157         XSTRING (canon)->data[i] = downvec[upvec[downvec[i]]];
 158
 159       compute_trt_inverse (XSTRING (canon)->data, XSTRING (eqv)->data);
 160     }
 161
 162   if (standard)
 163     {
 164       Vascii_downcase_table = down;
 165       Vascii_upcase_table = up;
 166       Vascii_canon_table = canon;
 167       Vascii_eqv_table = eqv;
 168     }
 169   else
 170     {
 171       current_buffer->downcase_table = down;
 172       current_buffer->upcase_table = up;
 173       current_buffer->case_canon_table = canon;
 174       current_buffer->case_eqv_table = eqv;
 175     }
 176   return table;
 177 }
 178 \f
 179 /* Given a translate table TRT, store the inverse mapping into INVERSE.
 180    Since TRT is not one-to-one, INVERSE is not a simple mapping.
 181    Instead, it divides the space of characters into equivalence classes.
 182    All characters in a given class form one circular list, chained through
 183    the elements of INVERSE.  */
 184
 185 void
 186 compute_trt_inverse (trt, inverse)
 187      register unsigned char *trt;
 188      register unsigned char *inverse;
 189 {
 190   register int i = 0400;
 191   register unsigned char c, q;
 192
 193   while (i--)
 194     inverse[i] = i;
 195   i = 0400;
 196   while (i--)
 197     {
 198       if ((q = trt[i]) != (unsigned char) i)
 199         {
 200           c = inverse[q];
 201           inverse[q] = i;
 202           inverse[i] = c;
 203         }
 204     }
 205 }
 206 \f
 207 init_casetab_once ()
 208 {
 209   register int i;
 210   Lisp_Object tem;
 211
 212   tem = Fmake_string (make_number (256), make_number (0));
 213   Vascii_downcase_table = tem;
 214   Vascii_canon_table = tem;
 215
 216   for (i = 0; i < 256; i++)
 217     XSTRING (tem)->data[i] = (i >= 'A' && i <= 'Z') ? i + 040 : i;
 218
 219   tem = Fmake_string (make_number (256), make_number (0));
 220   Vascii_upcase_table = tem;
 221   Vascii_eqv_table = tem;
 222
 223   for (i = 0; i < 256; i++)
 224     XSTRING (tem)->data[i]
 225       = ((i >= 'A' && i <= 'Z')
 226          ? i + ('a' - 'A')
 227          : ((i >= 'a' && i <= 'z')
 228             ? i + ('A' - 'a')
 229             : i));
 230 }
 231
 232 syms_of_casetab ()
 233 {
 234   Qcase_table_p = intern ("case-table-p");
 235   staticpro (&Qcase_table_p);
 236   staticpro (&Vascii_downcase_table);
 237   staticpro (&Vascii_upcase_table);
 238   staticpro (&Vascii_canon_table);
 239   staticpro (&Vascii_eqv_table);
 240
 241   defsubr (&Scase_table_p);
 242   defsubr (&Scurrent_case_table);
 243   defsubr (&Sstandard_case_table);
 244   defsubr (&Sset_case_table);
 245   defsubr (&Sset_standard_case_table);
 246
 247 #if 0
 248   DEFVAR_LISP ("ascii-downcase-table", &Vascii_downcase_table,
 249                "String mapping ASCII characters to lowercase equivalents.");
 250   DEFVAR_LISP ("ascii-upcase-table", &Vascii_upcase_table,
 251                "String mapping ASCII characters to uppercase equivalents.");
 252 #endif
 253 }