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[emacs.git] / src / casetab.c
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1 /* GNU Emacs routines to deal with case tables.
2 Copyright (C) 1987 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
6 GNU Emacs is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 1, or (at your option)
9 any later version.
11 GNU Emacs is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
20 /* Written by Howard Gayle. See chartab.c for details. */
22 #include "config.h"
23 #include "lisp.h"
24 #include "buffer.h"
26 Lisp_Object Qcase_table_p;
27 Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
28 Lisp_Object Vascii_canon_table, Vascii_eqv_table;
30 void compute_trt_inverse ();
32 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
33 "Return t iff ARG is a case table.\n\
34 See `set-case-table' for more information on these data structures.")
35 (table)
36 Lisp_Object table;
38 Lisp_Object down, up, canon, eqv;
39 down = Fcar_safe (table);
40 up = Fcar_safe (Fcdr_safe (table));
41 canon = Fcar_safe (Fcdr_safe (Fcdr_safe (table)));
42 eqv = Fcar_safe (Fcdr_safe (Fcdr_safe (Fcdr_safe (table))));
44 #define STRING256_P(obj) \
45 (XTYPE (obj) == Lisp_String && XSTRING (obj)->size == 256)
47 return (STRING256_P (down)
48 && (NILP (up) || STRING256_P (up))
49 && ((NILP (canon) && NILP (eqv))
50 || (STRING256_P (canon) && STRING256_P (eqv)))
51 ? Qt : Qnil);
54 static Lisp_Object
55 check_case_table (obj)
56 Lisp_Object obj;
58 register Lisp_Object tem;
60 while (tem = Fcase_table_p (obj), NILP (tem))
61 obj = wrong_type_argument (Qcase_table_p, obj, 0);
62 return (obj);
65 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
66 "Return the case table of the current buffer.")
69 Lisp_Object down, up, canon, eqv;
71 down = current_buffer->downcase_table;
72 up = current_buffer->upcase_table;
73 canon = current_buffer->case_canon_table;
74 eqv = current_buffer->case_eqv_table;
76 return Fcons (down, Fcons (up, Fcons (canon, Fcons (eqv, Qnil))));
79 DEFUN ("standard-case-table", Fstandard_case_table,
80 Sstandard_case_table, 0, 0, 0,
81 "Return the standard case table.\n\
82 This is the one used for new buffers.")
85 return Fcons (Vascii_downcase_table,
86 Fcons (Vascii_upcase_table,
87 Fcons (Vascii_canon_table,
88 Fcons (Vascii_eqv_table, Qnil))));
91 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
92 "Select a new case table for the current buffer.\n\
93 A case table is a list (DOWNCASE UPCASE CANONICALIZE EQUIVALENCES)\n\
94 where each element is either nil or a string of length 256.\n\
95 DOWNCASE maps each character to its lower-case equivalent.\n\
96 UPCASE maps each character to its upper-case equivalent;\n\
97 if lower and upper case characters are in 1-1 correspondence,\n\
98 you may use nil and the upcase table will be deduced from DOWNCASE.\n\
99 CANONICALIZE maps each character to a canonical equivalent;\n\
100 any two characters that are related by case-conversion have the same\n\
101 canonical equivalent character.\n\
102 EQUIVALENCES is a map that cyclicly permutes each equivalence class\n\
103 (of characters with the same canonical equivalent).\n\
104 Both CANONICALIZE and EQUIVALENCES may be nil, in which case\n\
105 both are deduced from DOWNCASE and UPCASE.")
106 (table)
107 Lisp_Object table;
109 set_case_table (table, 0);
112 DEFUN ("set-standard-case-table",
113 Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
114 "Select a new standard case table for new buffers.\n\
115 See `set-case-table' for more info on case tables.")
116 (table)
117 Lisp_Object table;
119 set_case_table (table, 1);
122 set_case_table (table, standard)
123 Lisp_Object table;
124 int standard;
126 Lisp_Object down, up, canon, eqv;
128 check_case_table (table);
130 down = Fcar_safe (table);
131 up = Fcar_safe (Fcdr_safe (table));
132 canon = Fcar_safe (Fcdr_safe (Fcdr_safe (table)));
133 eqv = Fcar_safe (Fcdr_safe (Fcdr_safe (Fcdr_safe (table))));
135 if (NILP (up))
137 up = Fmake_string (make_number (256), make_number (0));
138 compute_trt_inverse (XSTRING (down)->data, XSTRING (up)->data);
141 if (NILP (canon))
143 register int i;
144 unsigned char *upvec = XSTRING (up)->data;
145 unsigned char *downvec = XSTRING (down)->data;
147 canon = Fmake_string (make_number (256), make_number (0));
148 eqv = Fmake_string (make_number (256), make_number (0));
150 /* Set up the CANON vector; for each character,
151 this sequence of upcasing and downcasing ought to
152 get the "preferred" lowercase equivalent. */
153 for (i = 0; i < 256; i++)
154 XSTRING (canon)->data[i] = downvec[upvec[downvec[i]]];
156 compute_trt_inverse (XSTRING (canon)->data, XSTRING (eqv)->data);
159 if (standard)
161 Vascii_downcase_table = down;
162 Vascii_upcase_table = up;
163 Vascii_canon_table = canon;
164 Vascii_eqv_table = eqv;
166 else
168 current_buffer->downcase_table = down;
169 current_buffer->upcase_table = up;
170 current_buffer->case_canon_table = canon;
171 current_buffer->case_eqv_table = eqv;
173 return table;
176 /* Given a translate table TRT, store the inverse mapping into INVERSE.
177 Since TRT is not one-to-one, INVERSE is not a simple mapping.
178 Instead, it divides the space of characters into equivalence classes.
179 All characters in a given class form one circular list, chained through
180 the elements of INVERSE. */
182 void
183 compute_trt_inverse (trt, inverse)
184 register unsigned char *trt;
185 register unsigned char *inverse;
187 register int i = 0400;
188 register unsigned char c, q;
190 while (i--)
191 inverse[i] = i;
192 i = 0400;
193 while (i--)
195 if ((q = trt[i]) != (unsigned char) i)
197 c = inverse[q];
198 inverse[q] = i;
199 inverse[i] = c;
204 init_casetab_once ()
206 register int i;
207 Lisp_Object tem;
209 tem = Fmake_string (make_number (256), make_number (0));
210 Vascii_downcase_table = tem;
211 Vascii_canon_table = tem;
213 for (i = 0; i < 256; i++)
214 XSTRING (tem)->data[i] = (i >= 'A' && i <= 'Z') ? i + 040 : i;
216 tem = Fmake_string (make_number (256), make_number (0));
217 Vascii_upcase_table = tem;
218 Vascii_eqv_table = tem;
220 for (i = 0; i < 256; i++)
221 XSTRING (tem)->data[i]
222 = ((i >= 'A' && i <= 'Z')
223 ? i + ('a' - 'A')
224 : ((i >= 'a' && i <= 'z')
225 ? i + ('A' - 'a')
226 : i));
229 syms_of_casetab ()
231 Qcase_table_p = intern ("case-table-p");
232 staticpro (&Qcase_table_p);
233 staticpro (&Vascii_downcase_table);
234 staticpro (&Vascii_upcase_table);
235 staticpro (&Vascii_canon_table);
236 staticpro (&Vascii_eqv_table);
238 defsubr (&Scase_table_p);
239 defsubr (&Scurrent_case_table);
240 defsubr (&Sstandard_case_table);
241 defsubr (&Sset_case_table);
242 defsubr (&Sset_standard_case_table);
244 #if 0
245 DEFVAR_LISP ("ascii-downcase-table", &Vascii_downcase_table,
246 "String mapping ASCII characters to lowercase equivalents.");
247 DEFVAR_LISP ("ascii-upcase-table", &Vascii_upcase_table,
248 "String mapping ASCII characters to uppercase equivalents.");
249 #endif