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1 /* GNU Emacs routines to deal with case tables.
2 Copyright (C) 1993-1994, 2001-2011 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 #include <setjmp.h>
23 #include "lisp.h"
24 #include "buffer.h"
25 #include "character.h"
26
27 static Lisp_Object Qcase_table_p, Qcase_table;
28 Lisp_Object Vascii_downcase_table;
29 static Lisp_Object Vascii_upcase_table;
30 Lisp_Object Vascii_canon_table;
31 static Lisp_Object Vascii_eqv_table;
32
33 static void set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt);
34 static void set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
35 static void shuffle (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
36
37 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
38 doc: /* Return t if OBJECT is a case table.
39 See `set-case-table' for more information on these data structures. */)
40 (Lisp_Object object)
41 {
42 Lisp_Object up, canon, eqv;
43
44 if (! CHAR_TABLE_P (object))
45 return Qnil;
46 if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
47 return Qnil;
48
49 up = XCHAR_TABLE (object)->extras[0];
50 canon = XCHAR_TABLE (object)->extras[1];
51 eqv = XCHAR_TABLE (object)->extras[2];
52
53 return ((NILP (up) || CHAR_TABLE_P (up))
54 && ((NILP (canon) && NILP (eqv))
55 || (CHAR_TABLE_P (canon)
56 && (NILP (eqv) || CHAR_TABLE_P (eqv))))
57 ? Qt : Qnil);
58 }
59
60 static Lisp_Object
61 check_case_table (Lisp_Object obj)
62 {
63 CHECK_TYPE (!NILP (Fcase_table_p (obj)), Qcase_table_p, obj);
64 return (obj);
65 }
66
67 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
68 doc: /* Return the case table of the current buffer. */)
69 (void)
70 {
71 return BVAR (current_buffer, downcase_table);
72 }
73
74 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
75 doc: /* Return the standard case table.
76 This is the one used for new buffers. */)
77 (void)
78 {
79 return Vascii_downcase_table;
80 }
81
82 static Lisp_Object set_case_table (Lisp_Object table, int standard);
83
84 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
85 doc: /* Select a new case table for the current buffer.
86 A case table is a char-table which maps characters
87 to their lower-case equivalents. It also has three \"extra\" slots
88 which may be additional char-tables or nil.
89 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
90 UPCASE maps each non-upper-case character to its upper-case equivalent.
91 (The value in UPCASE for an upper-case character is never used.)
92 If lower and upper case characters are in 1-1 correspondence,
93 you may use nil and the upcase table will be deduced from DOWNCASE.
94 CANONICALIZE maps each character to a canonical equivalent;
95 any two characters that are related by case-conversion have the same
96 canonical equivalent character; it may be nil, in which case it is
97 deduced from DOWNCASE and UPCASE.
98 EQUIVALENCES is a map that cyclically permutes each equivalence class
99 (of characters with the same canonical equivalent); it may be nil,
100 in which case it is deduced from CANONICALIZE. */)
101 (Lisp_Object table)
102 {
103 return set_case_table (table, 0);
104 }
105
106 DEFUN ("set-standard-case-table", Fset_standard_case_table,
107 Sset_standard_case_table, 1, 1, 0,
108 doc: /* Select a new standard case table for new buffers.
109 See `set-case-table' for more info on case tables. */)
110 (Lisp_Object table)
111 {
112 return set_case_table (table, 1);
113 }
114
115 static Lisp_Object
116 set_case_table (Lisp_Object table, int standard)
117 {
118 Lisp_Object up, canon, eqv;
119
120 check_case_table (table);
121
122 up = XCHAR_TABLE (table)->extras[0];
123 canon = XCHAR_TABLE (table)->extras[1];
124 eqv = XCHAR_TABLE (table)->extras[2];
125
126 if (NILP (up))
127 {
128 up = Fmake_char_table (Qcase_table, Qnil);
129 map_char_table (set_identity, Qnil, table, up);
130 map_char_table (shuffle, Qnil, table, up);
131 XCHAR_TABLE (table)->extras[0] = up;
132 }
133
134 if (NILP (canon))
135 {
136 canon = Fmake_char_table (Qcase_table, Qnil);
137 XCHAR_TABLE (table)->extras[1] = canon;
138 map_char_table (set_canon, Qnil, table, table);
139 }
140
141 if (NILP (eqv))
142 {
143 eqv = Fmake_char_table (Qcase_table, Qnil);
144 map_char_table (set_identity, Qnil, canon, eqv);
145 map_char_table (shuffle, Qnil, canon, eqv);
146 XCHAR_TABLE (table)->extras[2] = eqv;
147 }
148
149 /* This is so set_image_of_range_1 in regex.c can find the EQV table. */
150 XCHAR_TABLE (canon)->extras[2] = eqv;
151
152 if (standard)
153 {
154 Vascii_downcase_table = table;
155 Vascii_upcase_table = up;
156 Vascii_canon_table = canon;
157 Vascii_eqv_table = eqv;
158 }
159 else
160 {
161 BVAR (current_buffer, downcase_table) = table;
162 BVAR (current_buffer, upcase_table) = up;
163 BVAR (current_buffer, case_canon_table) = canon;
164 BVAR (current_buffer, case_eqv_table) = eqv;
165 }
166
167 return table;
168 }
169 \f
170 /* The following functions are called in map_char_table. */
171
172 /* Set CANON char-table element for characters in RANGE to a
173 translated ELT by UP and DOWN char-tables. This is done only when
174 ELT is a character. The char-tables CANON, UP, and DOWN are in
175 CASE_TABLE. */
176
177 static void
178 set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt)
179 {
180 Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
181 Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
182
183 if (NATNUMP (elt))
184 Fset_char_table_range (canon, range, Faref (case_table, Faref (up, elt)));
185 }
186
187 /* Set elements of char-table TABLE for C to C itself. C may be a
188 cons specifying a character range. In that case, set characters in
189 that range to themselves. This is done only when ELT is a
190 character. This is called in map_char_table. */
191
192 static void
193 set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt)
194 {
195 if (NATNUMP (elt))
196 {
197 int from;
198 unsigned to;
199
200 if (CONSP (c))
201 {
202 from = XINT (XCAR (c));
203 to = XINT (XCDR (c));
204 }
205 else
206 from = to = XINT (c);
207 for (to++; 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;
223 unsigned to;
224
225 if (CONSP (c))
226 {
227 from = XINT (XCAR (c));
228 to = XINT (XCDR (c));
229 }
230 else
231 from = to = XINT (c);
232
233 for (to++; 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;
247 DEFSYM (Qcase_table, "case-table");
248
249 /* Intern this now in case it isn't already done.
250 Setting this variable twice is harmless.
251 But don't staticpro it here--that is done in alloc.c. */
252 Qchar_table_extra_slots = intern_c_string ("char-table-extra-slots");
253
254 /* Now we are ready to set up this property, so we can
255 create char tables. */
256 Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
257
258 down = Fmake_char_table (Qcase_table, Qnil);
259 Vascii_downcase_table = down;
260 XCHAR_TABLE (down)->purpose = Qcase_table;
261
262 for (i = 0; i < 128; i++)
263 {
264 int c = (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i;
265 CHAR_TABLE_SET (down, i, make_number (c));
266 }
267
268 XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
269
270 up = Fmake_char_table (Qcase_table, Qnil);
271 XCHAR_TABLE (down)->extras[0] = up;
272
273 for (i = 0; i < 128; i++)
274 {
275 int c = ((i >= 'A' && i <= 'Z') ? i + ('a' - 'A')
276 : ((i >= 'a' && i <= 'z') ? i + ('A' - 'a')
277 : i));
278 CHAR_TABLE_SET (up, i, make_number (c));
279 }
280
281 XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
282
283 /* Fill in what isn't filled in. */
284 set_case_table (down, 1);
285 }
286
287 void
288 syms_of_casetab (void)
289 {
290 DEFSYM (Qcase_table_p, "case-table-p");
291
292 staticpro (&Vascii_canon_table);
293 staticpro (&Vascii_downcase_table);
294 staticpro (&Vascii_eqv_table);
295 staticpro (&Vascii_upcase_table);
296
297 defsubr (&Scase_table_p);
298 defsubr (&Scurrent_case_table);
299 defsubr (&Sstandard_case_table);
300 defsubr (&Sset_case_table);
301 defsubr (&Sset_standard_case_table);
302 }