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
5This file is part of GNU Emacs.
6
7GNU Emacs is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2, or (at your option)
10any later version.
11
12GNU Emacs is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with GNU Emacs; see the file COPYING.  If not, write to
19the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20Boston, 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
29Lisp_Object Qcase_table_p, Qcase_table;
30Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
31Lisp_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.  */
35int case_temp1;
36Lisp_Object case_temp2;
37
38static void set_canon ();
39static void set_identity ();
40static void shuffle ();
41
42DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
43       doc: /* Return t iff OBJECT is a case table.
44See `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
66static Lisp_Object
67check_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
74DEFUN ("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
81DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
82       doc: /* Return the standard case table.
83This is the one used for new buffers.  */)
84     ()
85{
86  return Vascii_downcase_table;
87}
88
89static Lisp_Object set_case_table ();
90
91DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
92       doc: /* Select a new case table for the current buffer.
93A case table is a char-table which maps characters
94to their lower-case equivalents.  It also has three \"extra\" slots
95which may be additional char-tables or nil.
96These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
97UPCASE 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.
101CANONICALIZE 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.
105EQUIVALENCES 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
114DEFUN ("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.
116See `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
123static Lisp_Object
124set_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
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
187static void
188set_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
201static void
202set_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
214static void
215shuffle (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
226void
227init_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
270void
271syms_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) */
290