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/* GNU Emacs routines to deal with case tables.
Copyright (C) 1993, 1994 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* Written by Howard Gayle. See chartab.c for details. */
#include <config.h>
#include "lisp.h"
#include "buffer.h"
Lisp_Object Qcase_table_p, Qcase_table;
Lisp_Object Vascii_downcase_table, Vascii_upcase_table;
Lisp_Object Vascii_canon_table, Vascii_eqv_table;
static void compute_trt_inverse ();
DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
"Return t iff OBJECT is a case table.\n\
See `set-case-table' for more information on these data structures.")
(object)
Lisp_Object object;
{
Lisp_Object up, canon, eqv;
if (! CHAR_TABLE_P (object))
return Qnil;
if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
return Qnil;
up = XCHAR_TABLE (object)->extras[0];
canon = XCHAR_TABLE (object)->extras[1];
eqv = XCHAR_TABLE (object)->extras[2];
return ((NILP (up) || CHAR_TABLE_P (up))
&& ((NILP (canon) && NILP (eqv))
|| (CHAR_TABLE_P (canon)
&& (NILP (eqv) || CHAR_TABLE_P (eqv))))
? Qt : Qnil);
}
static Lisp_Object
check_case_table (obj)
Lisp_Object obj;
{
register Lisp_Object tem;
while (tem = Fcase_table_p (obj), NILP (tem))
obj = wrong_type_argument (Qcase_table_p, obj);
return (obj);
}
DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
"Return the case table of the current buffer.")
()
{
return current_buffer->downcase_table;
}
DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
"Return the standard case table.\n\
This is the one used for new buffers.")
()
{
return Vascii_downcase_table;
}
static Lisp_Object set_case_table ();
DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
"Select a new case table for the current buffer.\n\
A case table is a char-table which maps characters\n\
to their lower-case equivalents. It also has three \"extra\" slots\n\
which may be additional char-tables or nil.\n\
These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.\n\
UPCASE maps each character to its upper-case equivalent;\n\
if lower and upper case characters are in 1-1 correspondence,\n\
you may use nil and the upcase table will be deduced from DOWNCASE.\n\
CANONICALIZE maps each character to a canonical equivalent;\n\
any two characters that are related by case-conversion have the same\n\
canonical equivalent character; it may be nil, in which case it is\n\
deduced from DOWNCASE and UPCASE.\n\
EQUIVALENCES is a map that cyclicly permutes each equivalence class\n\
(of characters with the same canonical equivalent); it may be nil,\n\
in which case it is deduced from CANONICALIZE.")
(table)
Lisp_Object table;
{
return set_case_table (table, 0);
}
DEFUN ("set-standard-case-table", Fset_standard_case_table, Sset_standard_case_table, 1, 1, 0,
"Select a new standard case table for new buffers.\n\
See `set-case-table' for more info on case tables.")
(table)
Lisp_Object table;
{
return set_case_table (table, 1);
}
static Lisp_Object
set_case_table (table, standard)
Lisp_Object table;
int standard;
{
Lisp_Object up, canon, eqv;
check_case_table (table);
up = XCHAR_TABLE (table)->extras[0];
canon = XCHAR_TABLE (table)->extras[1];
eqv = XCHAR_TABLE (table)->extras[2];
if (NILP (up))
{
up = Fmake_char_table (Qcase_table, Qnil);
compute_trt_inverse (XCHAR_TABLE (table), XCHAR_TABLE (up));
XCHAR_TABLE (table)->extras[0] = up;
}
if (NILP (canon))
{
register int i;
Lisp_Object *upvec = XCHAR_TABLE (up)->contents;
Lisp_Object *downvec = XCHAR_TABLE (table)->contents;
canon = Fmake_char_table (Qcase_table, Qnil);
/* Set up the CANON vector; for each character,
this sequence of upcasing and downcasing ought to
get the "preferred" lowercase equivalent. */
for (i = 0; i < 256; i++)
XCHAR_TABLE (canon)->contents[i] = downvec[upvec[downvec[i]]];
XCHAR_TABLE (table)->extras[1] = canon;
}
if (NILP (eqv))
{
eqv = Fmake_char_table (Qcase_table, Qnil);
compute_trt_inverse (XCHAR_TABLE (canon), XCHAR_TABLE (eqv));
XCHAR_TABLE (table)->extras[2] = eqv;
}
if (standard)
Vascii_downcase_table = table;
else
{
current_buffer->downcase_table = table;
current_buffer->upcase_table = up;
current_buffer->case_canon_table = canon;
current_buffer->case_eqv_table = eqv;
}
return table;
}
/* Given a translate table TRT, store the inverse mapping into INVERSE.
Since TRT is not one-to-one, INVERSE is not a simple mapping.
Instead, it divides the space of characters into equivalence classes.
All characters in a given class form one circular list, chained through
the elements of INVERSE. */
static void
compute_trt_inverse (trt, inverse)
struct Lisp_Char_Table *trt, *inverse;
{
register int i = 0400;
register unsigned char c, q;
while (i--)
inverse->contents[i] = i;
i = 0400;
while (i--)
{
if ((q = trt->contents[i]) != (unsigned char) i)
{
c = inverse->contents[q];
inverse->contents[q] = i;
inverse->contents[i] = c;
}
}
}
init_casetab_once ()
{
register int i;
Lisp_Object down, up;
Qcase_table = intern ("case-table");
staticpro (&Qcase_table);
/* Intern this now in case it isn't already done.
Setting this variable twice is harmless.
But don't staticpro it here--that is done in alloc.c. */
Qchar_table_extra_slots = intern ("char-table-extra-slots");
/* Now we are ready to set up this property, so we can
create char tables. */
Fput (Qcase_table, Qchar_table_extra_slots, make_number (3));
down = Fmake_char_table (Qcase_table, Qnil);
Vascii_downcase_table = down;
for (i = 0; i < 256; i++)
XCHAR_TABLE (down)->contents[i] = (i >= 'A' && i <= 'Z') ? i + 040 : i;
XCHAR_TABLE (down)->extras[1] = Fcopy_sequence (down);
up = Fmake_char_table (Qcase_table, Qnil);
XCHAR_TABLE (down)->extras[0] = up;
for (i = 0; i < 256; i++)
XCHAR_TABLE (up)->contents[i]
= ((i >= 'A' && i <= 'Z')
? i + ('a' - 'A')
: ((i >= 'a' && i <= 'z')
? i + ('A' - 'a')
: i));
XCHAR_TABLE (down)->extras[2] = Fcopy_sequence (up);
}
syms_of_casetab ()
{
Qcase_table_p = intern ("case-table-p");
staticpro (&Qcase_table_p);
staticpro (&Vascii_downcase_table);
defsubr (&Scase_table_p);
defsubr (&Scurrent_case_table);
defsubr (&Sstandard_case_table);
defsubr (&Sset_case_table);
defsubr (&Sset_standard_case_table);
}
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