src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1993, 1994, 2002, 2003, 2004,
   3                  2005, 2006 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, USA.  */
  21
  22 /* Written by Howard Gayle.  */
  23
  24 #include <config.h>
  25 #include "lisp.h"
  26 #include "buffer.h"
  27 #include "charset.h"
  28
  29 Lisp_Object Qcase_table_p, Qcase_table;
  30 Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
  31 Lisp_Object Vascii_canon_table, Vascii_eqv_table;
  32
  33 /* Used as a temporary in DOWNCASE and other macros in lisp.h.  No
  34    need to mark it, since it is used only very temporarily.  */
  35 int case_temp1;
  36 Lisp_Object case_temp2;
  37
  38 static void set_canon ();
  39 static void set_identity ();
  40 static void shuffle ();
  41
  42 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
  43        doc: /* Return t iff OBJECT is a case table.
  44 See `set-case-table' for more information on these data structures.  */)
  45      (object)
  46      Lisp_Object object;
  47 {
  48   Lisp_Object up, canon, eqv;
  49
  50   if (! CHAR_TABLE_P (object))
  51     return Qnil;
  52   if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
  53     return Qnil;
  54
  55   up = XCHAR_TABLE (object)->extras[0];
  56   canon = XCHAR_TABLE (object)->extras[1];
  57   eqv = XCHAR_TABLE (object)->extras[2];
  58
  59   return ((NILP (up) || CHAR_TABLE_P (up))
  60           && ((NILP (canon) && NILP (eqv))
  61               || (CHAR_TABLE_P (canon)
  62                   && (NILP (eqv) || CHAR_TABLE_P (eqv))))
  63           ? Qt : Qnil);
  64 }
  65
  66 static Lisp_Object
  67 check_case_table (obj)
  68      Lisp_Object obj;
  69 {
  70   register Lisp_Object tem;
  71
  72   while (tem = Fcase_table_p (obj), NILP (tem))
  73     obj = wrong_type_argument (Qcase_table_p, obj);
  74   return (obj);
  75 }
  76
  77 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  78        doc: /* Return the case table of the current buffer.  */)
  79      ()
  80 {
  81   return current_buffer->downcase_table;
  82 }
  83
  84 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
  85        doc: /* Return the standard case table.
  86 This is the one used for new buffers.  */)
  87      ()
  88 {
  89   return Vascii_downcase_table;
  90 }
  91
  92 static Lisp_Object set_case_table ();
  93
  94 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  95        doc: /* Select a new case table for the current buffer.
  96 A case table is a char-table which maps characters
  97 to their lower-case equivalents.  It also has three \"extra\" slots
  98 which may be additional char-tables or nil.
  99 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
 100 UPCASE maps each non-upper-case character to its upper-case equivalent.
 101  (The value in UPCASE for an upper-case character is never used.)
 102  If lower and upper case characters are in 1-1 correspondence,
 103  you may use nil and the upcase table will be deduced from DOWNCASE.
 104 CANONICALIZE maps each character to a canonical equivalent;
 105  any two characters that are related by case-conversion have the same
 106  canonical equivalent character; it may be nil, in which case it is
 107  deduced from DOWNCASE and UPCASE.
 108 EQUIVALENCES is a map that cyclicly permutes each equivalence class
 109  (of characters with the same canonical equivalent); it may be nil,
 110  in which case it is deduced from CANONICALIZE.  */)
 111      (table)
 112      Lisp_Object table;
 113 {
 114   return set_case_table (table, 0);
 115 }
 116
 117 DEFUN ("set-standard-case-table", Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
 118        doc: /* Select a new standard case table for new buffers.
 119 See `set-case-table' for more info on case tables.  */)
 120      (table)
 121      Lisp_Object table;
 122 {
 123   return set_case_table (table, 1);
 124 }
 125
 126 static Lisp_Object
 127 set_case_table (table, standard)
 128      Lisp_Object table;
 129      int standard;
 130 {
 131   Lisp_Object up, canon, eqv;
 132   Lisp_Object indices[3];
 133
 134   check_case_table (table);
 135
 136   up = XCHAR_TABLE (table)->extras[0];
 137   canon = XCHAR_TABLE (table)->extras[1];
 138   eqv = XCHAR_TABLE (table)->extras[2];
 139
 140   if (NILP (up))
 141     {
 142       up = Fmake_char_table (Qcase_table, Qnil);
 143       map_char_table (set_identity, Qnil, table, table, up, 0, indices);
 144       map_char_table (shuffle, Qnil, table, table, up, 0, indices);
 145       XCHAR_TABLE (table)->extras[0] = up;
 146     }
 147
 148   if (NILP (canon))
 149     {
 150       canon = Fmake_char_table (Qcase_table, Qnil);
 151       XCHAR_TABLE (table)->extras[1] = canon;
 152       map_char_table (set_canon, Qnil, table, table, table, 0, indices);
 153     }
 154
 155   if (NILP (eqv))
 156     {
 157       eqv = Fmake_char_table (Qcase_table, Qnil);
 158       map_char_table (set_identity, Qnil, canon, canon, eqv, 0, indices);
 159       map_char_table (shuffle, Qnil, canon, canon, eqv, 0, indices);
 160       XCHAR_TABLE (table)->extras[2] = eqv;
 161     }
 162
 163   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 164   XCHAR_TABLE (canon)->extras[2] = eqv;
 165
 166   if (standard)
 167     {
 168       Vascii_downcase_table = table;
 169       Vascii_upcase_table = up;
 170       Vascii_canon_table = canon;
 171       Vascii_eqv_table = eqv;
 172     }
 173   else
 174     {
 175       current_buffer->downcase_table = table;
 176       current_buffer->upcase_table = up;
 177       current_buffer->case_canon_table = canon;
 178       current_buffer->case_eqv_table = eqv;
 179     }
 180
 181   return table;
 182 }
 183 \f
 184 /* The following functions are called in map_char_table.  */
 185
 186 /*  Set CANON char-table element for C to a translated ELT by UP and
 187    DOWN char-tables.  This is done only when ELT is a character.  The
 188    char-tables CANON, UP, and DOWN are in CASE_TABLE.  */
 189
 190 static void
 191 set_canon (case_table, c, elt)
 192      Lisp_Object case_table, c, elt;
 193 {
 194   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 195   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 196
 197   if (NATNUMP (elt))
 198     Faset (canon, c, Faref (case_table, Faref (up, elt)));
 199 }
 200
 201 /* Set elements of char-table TABLE for C to C itself.  This is done
 202    only when ELT is a character.  This is called in map_char_table.  */
 203
 204 static void
 205 set_identity (table, c, elt)
 206      Lisp_Object table, c, elt;
 207 {
 208   if (NATNUMP (elt))
 209     Faset (table, c, c);
 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 (table, c, elt)
 219      Lisp_Object table, c, elt;
 220 {
 221   if (NATNUMP (elt) && !EQ (c, elt))
 222     {
 223       Lisp_Object tem = Faref (table, elt);
 224       Faset (table, elt, c);
 225       Faset (table, c, tem);
 226     }
 227 }
 228 \f
 229 void
 230 init_casetab_once ()
 231 {
 232   register int i;
 233   Lisp_Object down, up;
 234   Qcase_table = intern ("case-table");
 235   staticpro (&Qcase_table);
 236
 237   /* Intern this now in case it isn't already done.
 238      Setting this variable twice is harmless.
 239      But don't staticpro it here--that is done in alloc.c.  */
 240   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 241
 242   /* Now we are ready to set up this property, so we can
 243      create char tables.  */
 244   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 245
 246   down = Fmake_char_table (Qcase_table, Qnil);
 247   Vascii_downcase_table = down;
 248   XCHAR_TABLE (down)->purpose = Qcase_table;
 249
 250   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 251     XSETFASTINT (XCHAR_TABLE (down)->contents[i],
 252                  (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i);
 253
 254   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 255
 256   up = Fmake_char_table (Qcase_table, Qnil);
 257   XCHAR_TABLE (down)->extras[0] = up;
 258
 259   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 260     XSETFASTINT (XCHAR_TABLE (up)->contents[i],
 261                  ((i >= 'A' && i <= 'Z')
 262                   ? i + ('a' - 'A')
 263                   : ((i >= 'a' && i <= 'z')
 264                      ? i + ('A' - 'a')
 265                      : i)));
 266
 267   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 268 }
 269
 270 void
 271 syms_of_casetab ()
 272 {
 273   Qcase_table_p = intern ("case-table-p");
 274   staticpro (&Qcase_table_p);
 275
 276   staticpro (&Vascii_canon_table);
 277   staticpro (&Vascii_downcase_table);
 278   staticpro (&Vascii_eqv_table);
 279   staticpro (&Vascii_upcase_table);
 280
 281   defsubr (&Scase_table_p);
 282   defsubr (&Scurrent_case_table);
 283   defsubr (&Sstandard_case_table);
 284   defsubr (&Sset_case_table);
 285   defsubr (&Sset_standard_case_table);
 286 }
 287
 288 /* arch-tag: e06388ad-99fe-40ec-ba67-9d010fcc4916
 289    (do not change this comment) */