root/src/casetab.c

DEFINITIONS

1. DEFUN
2. check_case_table
3. DEFUN
4. DEFUN
5. DEFUN
6. DEFUN
7. set_case_table
8. set_canon
9. set_identity
10. shuffle
11. init_casetab_once
12. syms_of_casetab

     1 /* GNU Emacs routines to deal with case tables.
     2    Copyright (C) 1993-1994, 2001-2023 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 (at
    11 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 <https://www.gnu.org/licenses/>.  */
    20 
    21 #include <config.h>
    22 
    23 #include "lisp.h"
    24 #include "buffer.h"
    25 
    26 Lisp_Object Vascii_downcase_table;
    27 static Lisp_Object Vascii_upcase_table;
    28 Lisp_Object Vascii_canon_table;
    29 static Lisp_Object Vascii_eqv_table;
    30 
    31 static void set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt);
    32 static void set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
    33 static void shuffle (Lisp_Object table, Lisp_Object c, Lisp_Object elt);
    34 
    35 DEFUN ("case-table-p", Fcase_table_p, Scase_table_p, 1, 1, 0,
    36        doc: /* Return t if OBJECT is a case table.
    37 See `set-case-table' for more information on these data structures.  */)
    38   (Lisp_Object object)
    39 {
    40   Lisp_Object up, canon, eqv;
    41 
    42   if (! CHAR_TABLE_P (object))
    43     return Qnil;
    44   if (! EQ (XCHAR_TABLE (object)->purpose, Qcase_table))
    45     return Qnil;
    46 
    47   up = XCHAR_TABLE (object)->extras[0];
    48   canon = XCHAR_TABLE (object)->extras[1];
    49   eqv = XCHAR_TABLE (object)->extras[2];
    50 
    51   return ((NILP (up) || CHAR_TABLE_P (up))
    52           && ((NILP (canon) && NILP (eqv))
    53               || (CHAR_TABLE_P (canon)
    54                   && (NILP (eqv) || CHAR_TABLE_P (eqv))))
    55           ? Qt : Qnil);
    56 }
    57 
    58 static Lisp_Object
    59 check_case_table (Lisp_Object obj)
    60 {
    61   CHECK_TYPE (!NILP (Fcase_table_p (obj)), Qcase_table_p, obj);
    62   return (obj);
    63 }
    64 
    65 DEFUN ("current-case-table", Fcurrent_case_table, Scurrent_case_table, 0, 0, 0,
    66        doc: /* Return the case table of the current buffer.  */)
    67   (void)
    68 {
    69   return BVAR (current_buffer, downcase_table);
    70 }
    71 
    72 DEFUN ("standard-case-table", Fstandard_case_table, Sstandard_case_table, 0, 0, 0,
    73        doc: /* Return the standard case table.
    74 This is the one used for new buffers.  */)
    75   (void)
    76 {
    77   return Vascii_downcase_table;
    78 }
    79 
    80 static Lisp_Object set_case_table (Lisp_Object, bool);
    81 
    82 DEFUN ("set-case-table", Fset_case_table, Sset_case_table, 1, 1, 0,
    83        doc: /* Select a new case table for the current buffer.
    84 A case table is a char-table which maps characters
    85 to their lower-case equivalents.  It also has three \"extra\" slots
    86 which may be additional char-tables or nil.
    87 These slots are called UPCASE, CANONICALIZE and EQUIVALENCES.
    88 UPCASE maps each non-upper-case character to its upper-case equivalent.
    89  (The value in UPCASE for an upper-case character is never used.)
    90  If lower and upper case characters are in 1-1 correspondence,
    91  you may use nil and the upcase table will be deduced from DOWNCASE.
    92 CANONICALIZE maps each character to a canonical equivalent;
    93  any two characters that are related by case-conversion have the same
    94  canonical equivalent character; it may be nil, in which case it is
    95  deduced from DOWNCASE and UPCASE.
    96 EQUIVALENCES is a map that cyclically permutes each equivalence class
    97  (of characters with the same canonical equivalent); it may be nil,
    98  in which case it is deduced from CANONICALIZE.  */)
    99   (Lisp_Object table)
   100 {
   101   return set_case_table (table, 0);
   102 }
   103 
   104 DEFUN ("set-standard-case-table", Fset_standard_case_table,
   105        Sset_standard_case_table, 1, 1, 0,
   106        doc: /* Select a new standard case table for new buffers.
   107 See `set-case-table' for more info on case tables.  */)
   108   (Lisp_Object table)
   109 {
   110   return set_case_table (table, 1);
   111 }
   112 
   113 static Lisp_Object
   114 set_case_table (Lisp_Object table, bool standard)
   115 {
   116   Lisp_Object up, canon, eqv;
   117 
   118   check_case_table (table);
   119 
   120   up = XCHAR_TABLE (table)->extras[0];
   121   canon = XCHAR_TABLE (table)->extras[1];
   122   eqv = XCHAR_TABLE (table)->extras[2];
   123 
   124   if (NILP (up))
   125     {
   126       up = Fmake_char_table (Qcase_table, Qnil);
   127       map_char_table (set_identity, Qnil, table, up);
   128       map_char_table (shuffle, Qnil, table, up);
   129       set_char_table_extras (table, 0, up);
   130     }
   131 
   132   if (NILP (canon))
   133     {
   134       canon = Fmake_char_table (Qcase_table, Qnil);
   135       set_char_table_extras (table, 1, canon);
   136       map_char_table (set_canon, Qnil, table, table);
   137     }
   138 
   139   if (NILP (eqv))
   140     {
   141       eqv = Fmake_char_table (Qcase_table, Qnil);
   142       map_char_table (set_identity, Qnil, canon, eqv);
   143       map_char_table (shuffle, Qnil, canon, eqv);
   144       set_char_table_extras (table, 2, eqv);
   145     }
   146 
   147   /* This is so set_image_of_range_1 in regex-emacs.c can find the EQV
   148      table.  */
   149   set_char_table_extras (canon, 2, eqv);
   150 
   151   if (standard)
   152     {
   153       Vascii_downcase_table = table;
   154       Vascii_upcase_table = up;
   155       Vascii_canon_table = canon;
   156       Vascii_eqv_table = eqv;
   157     }
   158   else
   159     {
   160       bset_downcase_table (current_buffer, table);
   161       bset_upcase_table (current_buffer, up);
   162       bset_case_canon_table (current_buffer, canon);
   163       bset_case_eqv_table (current_buffer, eqv);
   164     }
   165 
   166   return table;
   167 }
   168 
   169 /* The following functions are called in map_char_table.  */
   170 
   171 /* Set CANON char-table element for characters in RANGE to a
   172    translated ELT by UP and DOWN char-tables.  This is done only when
   173    ELT is a character.  The char-tables CANON, UP, and DOWN are in
   174    CASE_TABLE.  */
   175 
   176 static void
   177 set_canon (Lisp_Object case_table, Lisp_Object range, Lisp_Object elt)
   178 {
   179   Lisp_Object up = XCHAR_TABLE (case_table)->extras[0];
   180   Lisp_Object canon = XCHAR_TABLE (case_table)->extras[1];
   181 
   182   if (FIXNATP (elt))
   183     Fset_char_table_range (canon, range, Faref (case_table, Faref (up, elt)));
   184 }
   185 
   186 /* Set elements of char-table TABLE for C to C itself.  C may be a
   187    cons specifying a character range.  In that case, set characters in
   188    that range to themselves.  This is done only when ELT is a
   189    character.  This is called in map_char_table.  */
   190 
   191 static void
   192 set_identity (Lisp_Object table, Lisp_Object c, Lisp_Object elt)
   193 {
   194   if (FIXNATP (elt))
   195     {
   196       int from, to;
   197 
   198       if (CONSP (c))
   199         {
   200           from = XFIXNUM (XCAR (c));
   201           to = XFIXNUM (XCDR (c));
   202         }
   203       else
   204         from = to = XFIXNUM (c);
   205 
   206       to++;
   207       for (; from < to; from++)
   208         CHAR_TABLE_SET (table, from, make_fixnum (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 (FIXNATP (elt))
   221     {
   222       int from, to;
   223 
   224       if (CONSP (c))
   225         {
   226           from = XFIXNUM (XCAR (c));
   227           to = XFIXNUM (XCDR (c));
   228         }
   229       else
   230         from = to = XFIXNUM (c);
   231 
   232       to++;
   233       for (; from < to; from++)
   234         {
   235           Lisp_Object tem = Faref (table, elt);
   236           Faset (table, elt, make_fixnum (from));
   237           Faset (table, make_fixnum (from), tem);
   238         }
   239     }
   240 }
   241 
   242 void
   243 init_casetab_once (void)
   244 {
   245   register int i;
   246   Lisp_Object down, up, eqv;
   247 
   248   DEFSYM (Qcase_table, "case-table");
   249   Fput (Qcase_table, Qchar_table_extra_slots, make_fixnum (3));
   250 
   251   down = Fmake_char_table (Qcase_table, Qnil);
   252   Vascii_downcase_table = down;
   253   set_char_table_purpose (down, Qcase_table);
   254 
   255   for (i = 0; i < 128; i++)
   256     {
   257       int c = (i >= 'A' && i <= 'Z') ? i + ('a' - 'A') : i;
   258       CHAR_TABLE_SET (down, i, make_fixnum (c));
   259     }
   260 
   261   set_char_table_extras (down, 1, Fcopy_sequence (down));
   262 
   263   up = Fmake_char_table (Qcase_table, Qnil);
   264   set_char_table_extras (down, 0, up);
   265 
   266   for (i = 0; i < 128; i++)
   267     {
   268       int c = (i >= 'a' && i <= 'z') ? i + ('A' - 'a') : i;
   269       CHAR_TABLE_SET (up, i, make_fixnum (c));
   270     }
   271 
   272   eqv = Fmake_char_table (Qcase_table, Qnil);
   273 
   274    for (i = 0; i < 128; i++)
   275      {
   276       int c = ((i >= 'A' && i <= 'Z') ? i + ('a' - 'A')
   277                : ((i >= 'a' && i <= 'z') ? i + ('A' - 'a')
   278                   : i));
   279       CHAR_TABLE_SET (eqv, i, make_fixnum (c));
   280     }
   281 
   282   set_char_table_extras (down, 2, eqv);
   283 
   284   /* Fill in what isn't filled in.  */
   285   set_case_table (down, 1);
   286 }
   287 
   288 void
   289 syms_of_casetab (void)
   290 {
   291   DEFSYM (Qcase_table_p, "case-table-p");
   292 
   293   staticpro (&Vascii_canon_table);
   294   staticpro (&Vascii_downcase_table);
   295   staticpro (&Vascii_eqv_table);
   296   staticpro (&Vascii_upcase_table);
   297 
   298   defsubr (&Scase_table_p);
   299   defsubr (&Scurrent_case_table);
   300   defsubr (&Sstandard_case_table);
   301   defsubr (&Sset_case_table);
   302   defsubr (&Sset_standard_case_table);
   303 }