src/casetab.c

   1 /* GNU Emacs routines to deal with case tables.
   2    Copyright (C) 1993, 1994, 2001, 2002, 2003, 2004,
   3                  2005, 2006, 2007  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   CHECK_TYPE (!NILP (Fcase_table_p (obj)), Qcase_table_p, obj);
  71   return (obj);
  72 }
  73
  74 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
  75        doc: /* Return the case table of the current buffer.  */)
  76      ()
  77 {
  78   return current_buffer->downcase_table;
  79 }
  80
  81 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
  82        doc: /* Return the standard case table.
  83 This is the one used for new buffers.  */)
  84      ()
  85 {
  86   return Vascii_downcase_table;
  87 }
  88
  89 static Lisp_Object set_case_table ();
  90
  91 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
  92        doc: /* Select a new case table for the current buffer.
  93 A case table is a char-table which maps characters
  94 to their lower-case equivalents.  It also has three \"extra\" slots
  95 which may be additional char-tables or nil.
  96 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
  97 UPCASE maps each non-upper-case character to its upper-case equivalent.
  98  (The value in UPCASE for an upper-case character is never used.)
  99  If lower and upper case characters are in 1-1 correspondence,
 100  you may use nil and the upcase table will be deduced from DOWNCASE.
 101 CANONICALIZE maps each character to a canonical equivalent;
 102  any two characters that are related by case-conversion have the same
 103  canonical equivalent character; it may be nil, in which case it is
 104  deduced from DOWNCASE and UPCASE.
 105 EQUIVALENCES is a map that cyclicly permutes each equivalence class
 106  (of characters with the same canonical equivalent); it may be nil,
 107  in which case it is deduced from CANONICALIZE.  */)
 108      (table)
 109      Lisp_Object table;
 110 {
 111   return set_case_table (table, 0);
 112 }
 113
 114 DEFUN ("set-standard-case-table", Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
 115        doc: /* Select a new standard case table for new buffers.
 116 See `set-case-table' for more info on case tables.  */)
 117      (table)
 118      Lisp_Object table;
 119 {
 120   return set_case_table (table, 1);
 121 }
 122
 123 static Lisp_Object
 124 set_case_table (table, standard)
 125      Lisp_Object table;
 126      int standard;
 127 {
 128   Lisp_Object up, canon, eqv;
 129   Lisp_Object indices[3];
 130
 131   check_case_table (table);
 132
 133   up = XCHAR_TABLE (table)->extras[0];
 134   canon = XCHAR_TABLE (table)->extras[1];
 135   eqv = XCHAR_TABLE (table)->extras[2];
 136
 137   if (NILP (up))
 138     {
 139       up = Fmake_char_table (Qcase_table, Qnil);
 140       map_char_table (set_identity, Qnil, table, table, up, 0, indices);
 141       map_char_table (shuffle, Qnil, table, table, up, 0, indices);
 142       XCHAR_TABLE (table)->extras[0] = up;
 143     }
 144
 145   if (NILP (canon))
 146     {
 147       canon = Fmake_char_table (Qcase_table, Qnil);
 148       XCHAR_TABLE (table)->extras[1] = canon;
 149       map_char_table (set_canon, Qnil, table, table, table, 0, indices);
 150     }
 151
 152   if (NILP (eqv))
 153     {
 154       eqv = Fmake_char_table (Qcase_table, Qnil);
 155       map_char_table (set_identity, Qnil, canon, canon, eqv, 0, indices);
 156       map_char_table (shuffle, Qnil, canon, canon, eqv, 0, indices);
 157       XCHAR_TABLE (table)->extras[2] = eqv;
 158     }
 159
 160   /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
 161   XCHAR_TABLE (canon)->extras[2] = eqv;
 162
 163   if (standard)
 164     {
 165       Vascii_downcase_table = table;
 166       Vascii_upcase_table = up;
 167       Vascii_canon_table = canon;
 168       Vascii_eqv_table = eqv;
 169     }
 170   else
 171     {
 172       current_buffer->downcase_table = table;
 173       current_buffer->upcase_table = up;
 174       current_buffer->case_canon_table = canon;
 175       current_buffer->case_eqv_table = eqv;
 176     }
 177
 178   return table;
 179 }
 180 \f
 181 /* The following functions are called in map_char_table.  */
 182
 183 /*  Set CANON char-table element for C to a translated ELT by UP and
 184    DOWN char-tables.  This is done only when ELT is a character.  The
 185    char-tables CANON, UP, and DOWN are in CASE_TABLE.  */
 186
 187 static void
 188 set_canon (case_table, c, elt)
 189      Lisp_Object case_table, c, elt;
 190 {
 191   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
 192   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
 193
 194   if (NATNUMP (elt))
 195     Faset (canon, c, Faref (case_table, Faref (up, elt)));
 196 }
 197
 198 /* Set elements of char-table TABLE for C to C itself.  This is done
 199    only when ELT is a character.  This is called in map_char_table.  */
 200
 201 static void
 202 set_identity (table, c, elt)
 203      Lisp_Object table, c, elt;
 204 {
 205   if (NATNUMP (elt))
 206     Faset (table, c, c);
 207 }
 208
 209 /* Permute the elements of TABLE (which is initially an identity
 210    mapping) so that it has one cycle for each equivalence class
 211    induced by the translation table on which map_char_table is
 212    operated.  */
 213
 214 static void
 215 shuffle (table, c, elt)
 216      Lisp_Object table, c, elt;
 217 {
 218   if (NATNUMP (elt) && !EQ (c, elt))
 219     {
 220       Lisp_Object tem = Faref (table, elt);
 221       Faset (table, elt, c);
 222       Faset (table, c, tem);
 223     }
 224 }
 225 \f
 226 void
 227 init_casetab_once ()
 228 {
 229   register int i;
 230   Lisp_Object down, up;
 231   Qcase_table = intern ("case-table");
 232   staticpro (&Qcase_table);
 233
 234   /* Intern this now in case it isn't already done.
 235      Setting this variable twice is harmless.
 236      But don't staticpro it here--that is done in alloc.c.  */
 237   Qchar_table_extra_slots = intern ("char-table-extra-slots");
 238
 239   /* Now we are ready to set up this property, so we can
 240      create char tables.  */
 241   Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
 242
 243   down = Fmake_char_table (Qcase_table, Qnil);
 244   Vascii_downcase_table = down;
 245   XCHAR_TABLE (down)->purpose = Qcase_table;
 246
 247   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 248     XSETFASTINT (XCHAR_TABLE (down)->contents[i],
 249                  (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i);
 250
 251   XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
 252
 253   up = Fmake_char_table (Qcase_table, Qnil);
 254   XCHAR_TABLE (down)->extras[0] = up;
 255
 256   for (i = 0; i < CHAR_TABLE_SINGLE_BYTE_SLOTS; i++)
 257     XSETFASTINT (XCHAR_TABLE (up)->contents[i],
 258                  ((i >= 'A' && i <= 'Z')
 259                   ? i + ('a' - 'A')
 260                   : ((i >= 'a' && i <= 'z')
 261                      ? i + ('A' - 'a')
 262                      : i)));
 263
 264   XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
 265
 266   /* Fill in what isn't filled in.  */
 267   set_case_table (down, 1);
 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) */