src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1993-1994, 2001-2015 Free Software Foundation, Inc.
   3
   4 Author: Howard Gayle
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software: you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation, either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <config.h>
  22
  23 #include "lisp.h"
  24 #include "character.h"
  25 #include "buffer.h"
  26
  27 Lisp_Object Vascii_downcase_table;
  28 static Lisp_Object Vascii_upcase_table;
  29 Lisp_Object Vascii_canon_table;
  30 static Lisp_Object Vascii_eqv_table;
  31
  32 static void set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt);
  33 static void set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
  34 static void shuffle (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
  35
  36 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
  37        doc: /* Return t if OBJECT is a case table.
  38 See `set-case-table' for more information on these data structures.  */)
  39   (Lisp_Object object)
  40 {
  41   Lisp_Object up, canon, eqv;
  42
  43   if (! CHAR_TABLE_P (object))
  44     return Qnil;
  45   if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
  46     return Qnil;
  47
  48   up = XCHAR_TABLE (object)->extras[0];
  49   canon = XCHAR_TABLE (object)->extras[1];
  50   eqv = XCHAR_TABLE (object)->extras[2];
  51
  52   return ((NILP (up) || CHAR_TABLE_P (up))
  53           && ((NILP (canon) && NILP (eqv))
  54               || (CHAR_TABLE_P (canon)
  55                   && (NILP (eqv) || CHAR_TABLE_P (eqv))))
  56           ? Qt : Qnil);
  57 }
  58
  59 static Lisp_Object
  60 check_case_table (Lisp_Object obj)
  61 {
  62   CHECK_TYPE (!NILP (Fcase_table_p (obj)), Qcase_table_p, obj);
  63   return (obj);
  64 }
  65
  66 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  67        doc: /* Return the case table of the current buffer.  */)
  68   (void)
  69 {
  70   return BVAR (current_buffer, downcase_table);
  71 }
  72
  73 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
  74        doc: /* Return the standard case table.
  75 This is the one used for new buffers.  */)
  76   (void)
  77 {
  78   return Vascii_downcase_table;
  79 }
  80
  81 static Lisp_Object set_case_table (Lisp_Object, bool);
  82
  83 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  84        doc: /* Select a new case table for the current buffer.
  85 A case table is a char-table which maps characters
  86 to their lower-case equivalents.  It also has three \"extra\" slots
  87 which may be additional char-tables or nil.
  88 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
  89 UPCASE maps each non-upper-case character to its upper-case equivalent.
  90  (The value in UPCASE for an upper-case character is never used.)
  91  If lower and upper case characters are in 1-1 correspondence,
  92  you may use nil and the upcase table will be deduced from DOWNCASE.
  93 CANONICALIZE maps each character to a canonical equivalent;
  94  any two characters that are related by case-conversion have the same
  95  canonical equivalent character; it may be nil, in which case it is
  96  deduced from DOWNCASE and UPCASE.
  97 EQUIVALENCES is a map that cyclically permutes each equivalence class
  98  (of characters with the same canonical equivalent); it may be nil,
  99  in which case it is deduced from CANONICALIZE.  */)
 100   (Lisp_Object table)
 101 {
 102   return set_case_table (table, 0);
 103 }
 104
 105 DEFUN ("set-standard-case-table", Fset_standard_case_table,
 106        Sset_standard_case_table, 1, 1, 0,
 107        doc: /* Select a new standard case table for new buffers.
 108 See `set-case-table' for more info on case tables.  */)
 109   (Lisp_Object table)
 110 {
 111   return set_case_table (table, 1);
 112 }
 113
 114 static Lisp_Object
 115 set_case_table (Lisp_Object table, bool standard)
 116 {
 117   Lisp_Object up, canon, eqv;
 118
 119   check_case_table (table);
 120
 121   up = XCHAR_TABLE (table)->extras[0];
 122   canon = XCHAR_TABLE (table)->extras[1];
 123   eqv = XCHAR_TABLE (table)->extras[2];
 124
 125   if (NILP (up))
 126     {
 127       up = Fmake_char_table (Qcase_table, Qnil);
 128       map_char_table (set_identity, Qnil, table, up);
 129       map_char_table (shuffle, Qnil, table, up);
 130       set_char_table_extras (table, 0, up);
 131     }
 132
 133   if (NILP (canon))
 134     {
 135       canon = Fmake_char_table (Qcase_table, Qnil);
 136       set_char_table_extras (table, 1, canon);
 137       map_char_table (set_canon, Qnil, table, table);
 138     }
 139
 140   if (NILP (eqv))
 141     {
 142       eqv = Fmake_char_table (Qcase_table, Qnil);
 143       map_char_table (set_identity, Qnil, canon, eqv);
 144       map_char_table (shuffle, Qnil, canon, eqv);
 145       set_char_table_extras (table, 2, eqv);
 146     }
 147
 148   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 149   set_char_table_extras (canon, 2, eqv);
 150
 151   if (standard)
 152     {
 153       Vascii_downcase_table = table;
 154       Vascii_upcase_table = up;
 155       Vascii_canon_table = canon;
 156       Vascii_eqv_table = eqv;
 157     }
 158   else
 159     {
 160       bset_downcase_table (current_buffer, table);
 161       bset_upcase_table (current_buffer, up);
 162       bset_case_canon_table (current_buffer, canon);
 163       bset_case_eqv_table (current_buffer, eqv);
 164     }
 165
 166   return table;
 167 }
 168 \f
 169 /* The following functions are called in map_char_table.  */
 170
 171 /* Set CANON char-table element for characters in RANGE to a
 172    translated ELT by UP and DOWN char-tables.  This is done only when
 173    ELT is a character.  The char-tables CANON, UP, and DOWN are in
 174    CASE_TABLE.  */
 175
 176 static void
 177 set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt)
 178 {
 179   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 180   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 181
 182   if (NATNUMP (elt))
 183     Fset_char_table_range (canon, range, Faref (case_table, Faref (up, elt)));
 184 }
 185
 186 /* Set elements of char-table TABLE for C to C itself.  C may be a
 187    cons specifying a character range.  In that case, set characters in
 188    that range to themselves.  This is done only when ELT is a
 189    character.  This is called in map_char_table.  */
 190
 191 static void
 192 set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt)
 193 {
 194   if (NATNUMP (elt))
 195     {
 196       int from, to;
 197
 198       if (CONSP (c))
 199         {
 200           from = XINT (XCAR (c));
 201           to = XINT (XCDR (c));
 202         }
 203       else
 204         from = to = XINT (c);
 205
 206       to++;
 207       for (; from < to; from++)
 208         CHAR_TABLE_SET (table, from, make_number (from));
 209     }
 210 }
 211
 212 /* Permute the elements of TABLE (which is initially an identity
 213    mapping) so that it has one cycle for each equivalence class
 214    induced by the translation table on which map_char_table is
 215    operated.  */
 216
 217 static void
 218 shuffle (Lisp_Object table, Lisp_Object c, Lisp_Object elt)
 219 {
 220   if (NATNUMP (elt))
 221     {
 222       int from, to;
 223
 224       if (CONSP (c))
 225         {
 226           from = XINT (XCAR (c));
 227           to = XINT (XCDR (c));
 228         }
 229       else
 230         from = to = XINT (c);
 231
 232       to++;
 233       for (; from < to; from++)
 234         {
 235           Lisp_Object tem = Faref (table, elt);
 236           Faset (table, elt, make_number (from));
 237           Faset (table, make_number (from), tem);
 238         }
 239     }
 240 }
 241 \f
 242 void
 243 init_casetab_once (void)
 244 {
 245   register int i;
 246   Lisp_Object down, up, eqv;
 247
 248   DEFSYM (Qcase_table, "case-table");
 249   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 250
 251   down = Fmake_char_table (Qcase_table, Qnil);
 252   Vascii_downcase_table = down;
 253   set_char_table_purpose (down, Qcase_table);
 254
 255   for (i = 0; i < 128; i++)
 256     {
 257       int c = (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i;
 258       CHAR_TABLE_SET (down, i, make_number (c));
 259     }
 260
 261   set_char_table_extras (down, 1, Fcopy_sequence (down));
 262
 263   up = Fmake_char_table (Qcase_table, Qnil);
 264   set_char_table_extras (down, 0, up);
 265
 266   for (i = 0; i < 128; i++)
 267     {
 268       int c = (i >= 'a' && i <= 'z') ? i + ('A' - 'a') : i;
 269       CHAR_TABLE_SET (up, i, make_number (c));
 270     }
 271
 272   eqv = Fmake_char_table (Qcase_table, Qnil);
 273
 274    for (i = 0; i < 128; i++)
 275      {
 276       int c = ((i >= 'A' && i <= 'Z') ? i + ('a' - 'A')
 277                : ((i >= 'a' && i <= 'z') ? i + ('A' - 'a')
 278                   : i));
 279       CHAR_TABLE_SET (eqv, i, make_number (c));
 280     }
 281
 282   set_char_table_extras (down, 2, eqv);
 283
 284   /* Fill in what isn't filled in.  */
 285   set_case_table (down, 1);
 286 }
 287
 288 void
 289 syms_of_casetab (void)
 290 {
 291   DEFSYM (Qcase_table_p, "case-table-p");
 292
 293   staticpro (&Vascii_canon_table);
 294   staticpro (&Vascii_downcase_table);
 295   staticpro (&Vascii_eqv_table);
 296   staticpro (&Vascii_upcase_table);
 297
 298   defsubr (&Scase_table_p);
 299   defsubr (&Scurrent_case_table);
 300   defsubr (&Sstandard_case_table);
 301   defsubr (&Sset_case_table);
 302   defsubr (&Sset_standard_case_table);
 303 }