(Vchar_coding_system_table): Remove this variable.

(Vcoding_system_safe_chars): New variable.
(intersection): Remove this function.
(find_safe_codings): Don't use Vchar_coding_system_table, but try
all codings in SAFE_CODINGS.
(Ffind_coding_systems_region_internal): Adjusted for the change of
find_safe_codings.  Get generic coding systems from
Vcoding_system_safe_chars.
(Fdefine_coding_system_internal): New function.
(syms_of_coding): Defsubr Sdefine_coding_system_internal.
Initialize and staticpro Vcoding_system_safe_chars.

1 files changed, 8 insertions, 164 deletions

diff --git a/src/coding.c b/src/coding.c
index b192f984489..f5b4f808681 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -506,8 +506,6 @@ Lisp_Object Vtranslation_table_for_input;
    to avoid infinite recursive call.  */
 static int inhibit_pre_post_conversion;
 
-/* Char-table containing safe coding systems of each character.  */
-Lisp_Object Vchar_coding_system_table;
 Lisp_Object Qchar_coding_system;
 
 /* Return `safe-chars' property of CODING_SYSTEM (symbol).  Don't check
@@ -6388,26 +6386,6 @@ highest priority.  */)
                                STRING_MULTIBYTE (string));
 }
 
-/* Return an intersection of lists L1 and L2.  */
-
-static Lisp_Object
-intersection (l1, l2)
-     Lisp_Object l1, l2;
-{
-  Lisp_Object val = Fcons (Qnil, Qnil), tail;
-
-  for (tail = val; CONSP (l1); l1 = XCDR (l1))
-    {
-      if (!NILP (Fmemq (XCAR (l1), l2)))
-        {
-          XSETCDR (tail, Fcons (XCAR (l1), Qnil));
-          tail = XCDR (tail);
-        }
-    }
-  return XCDR (val);
-}
-
-
 /*  Subroutine for Fsafe_coding_systems_region_internal.
 
     Return a list of coding systems that safely encode the multibyte
@@ -6427,133 +6405,6 @@ find_safe_codings (p, pend, safe_codings, work_table, single_byte_char_found)
      Lisp_Object safe_codings, work_table;
      int *single_byte_char_found;
 {
-  int c, len, idx;
-  Lisp_Object val;
-
-  while (p < pend)
-    {
-      c = STRING_CHAR_AND_LENGTH (p, pend - p, len);
-      p += len;
-      if (ASCII_BYTE_P (c))
-        /* We can ignore ASCII characters here.  */
-        continue;
-      if (SINGLE_BYTE_CHAR_P (c))
-        *single_byte_char_found = 1;
-      if (NILP (safe_codings))
-        continue;
-      /* Check the safe coding systems for C.  */
-      val = char_table_ref_and_index (work_table, c, &idx);
-      if (EQ (val, Qt))
-        /* This element was already checked.  Ignore it.  */
-        continue;
-      /* Remember that we checked this element.  */
-      CHAR_TABLE_SET (work_table, make_number (idx), Qt);
-
-      /* If there are some safe coding systems for C and we have
-         already found the other set of coding systems for the
-         different characters, get the intersection of them.  */
-      if (!EQ (safe_codings, Qt) && !NILP (val))
-        val = intersection (safe_codings, val);
-      safe_codings = val;
-    }
-  return safe_codings;
-}
-
-
-/* Return a list of coding systems that safely encode the text between
-   START and END.  If the text contains only ASCII or is unibyte,
-   return t.  */
-
-DEFUN ("find-coding-systems-region-internal",
-       Ffind_coding_systems_region_internal,
-       Sfind_coding_systems_region_internal, 2, 2, 0,
-       doc: /* Internal use only.  */)
-     (start, end)
-     Lisp_Object start, end;
-{
-  Lisp_Object work_table, safe_codings;
-  int non_ascii_p = 0;
-  int single_byte_char_found = 0;
-  const unsigned char *p1, *p1end, *p2, *p2end, *p;
-
-  if (STRINGP (start))
-    {
-      if (!STRING_MULTIBYTE (start))
-        return Qt;
-      p1 = SDATA (start), p1end = p1 + SBYTES (start);
-      p2 = p2end = p1end;
-      if (SCHARS (start) != SBYTES (start))
-        non_ascii_p = 1;
-    }
-  else
-    {
-      int from, to, stop;
-
-      CHECK_NUMBER_COERCE_MARKER (start);
-      CHECK_NUMBER_COERCE_MARKER (end);
-      if (XINT (start) < BEG || XINT (end) > Z || XINT (start) > XINT (end))
-        args_out_of_range (start, end);
-      if (NILP (current_buffer->enable_multibyte_characters))
-        return Qt;
-      from = CHAR_TO_BYTE (XINT (start));
-      to = CHAR_TO_BYTE (XINT (end));
-      stop = from < GPT_BYTE && GPT_BYTE < to ? GPT_BYTE : to;
-      p1 = BYTE_POS_ADDR (from), p1end = p1 + (stop - from);
-      if (stop == to)
-        p2 = p2end = p1end;
-      else
-        p2 = BYTE_POS_ADDR (stop), p2end = p2 + (to - stop);
-      if (XINT (end) - XINT (start) != to - from)
-        non_ascii_p = 1;
-    }
-
-  if (!non_ascii_p)
-    {
-      /* We are sure that the text contains no multibyte character.
-         Check if it contains eight-bit-graphic.  */
-      p = p1;
-      for (p = p1; p < p1end && ASCII_BYTE_P (*p); p++);
-      if (p == p1end)
-        {
-          for (p = p2; p < p2end && ASCII_BYTE_P (*p); p++);
-          if (p == p2end)
-            return Qt;
-        }
-    }
-
-  /* The text contains non-ASCII characters.  */
-  work_table = Fcopy_sequence (Vchar_coding_system_table);
-  safe_codings = find_safe_codings (p1, p1end, Qt, work_table,
-                                    &single_byte_char_found);
-  if (p2 < p2end)
-    safe_codings = find_safe_codings (p2, p2end, safe_codings, work_table,
-                                      &single_byte_char_found);
-
-  if (EQ (safe_codings, Qt))
-    ; /* Nothing to be done.  */
-  else if (!single_byte_char_found)
-    {
-      /* Append generic coding systems.  */
-      Lisp_Object args[2];
-      args[0] = safe_codings;
-      args[1] = Fchar_table_extra_slot (Vchar_coding_system_table,
-                                        make_number (0));
-      safe_codings = Fappend (2, args);
-    }
-  else
-    safe_codings = Fcons (Qraw_text,
-                          Fcons (Qemacs_mule,
-                                 Fcons (Qno_conversion, safe_codings)));
-  return safe_codings;
-}
-
-
-static Lisp_Object
-find_safe_codings_2 (p, pend, safe_codings, work_table, single_byte_char_found)
-     unsigned char *p, *pend;
-     Lisp_Object safe_codings, work_table;
-     int *single_byte_char_found;
-{
   int c, len, i;
   Lisp_Object val, ch;
   Lisp_Object prev, tail;
@@ -6597,9 +6448,9 @@ find_safe_codings_2 (p, pend, safe_codings, work_table, single_byte_char_found)
   return safe_codings;
 }
 
-DEFUN ("find-coding-systems-region-internal-2",
-       Ffind_coding_systems_region_internal_2,
-       Sfind_coding_systems_region_internal_2, 2, 2, 0,
+DEFUN ("find-coding-systems-region-internal",
+       Ffind_coding_systems_region_internal,
+       Sfind_coding_systems_region_internal, 2, 2, 0,
        doc: /* Internal use only.  */)
      (start, end)
      Lisp_Object start, end;
@@ -6659,11 +6510,11 @@ DEFUN ("find-coding-systems-region-internal-2",
   work_table = Fmake_char_table (Qchar_coding_system, Qnil);
   safe_codings = Fcopy_sequence (XCDR (Vcoding_system_safe_chars));
 
-  safe_codings = find_safe_codings_2 (p1, p1end, safe_codings, work_table,
-                                      &single_byte_char_found);
+  safe_codings = find_safe_codings (p1, p1end, safe_codings, work_table,
+                                    &single_byte_char_found);
   if (p2 < p2end)
-    safe_codings = find_safe_codings_2 (p2, p2end, safe_codings, work_table,
-                                        &single_byte_char_found);
+    safe_codings = find_safe_codings (p2, p2end, safe_codings, work_table,
+                                      &single_byte_char_found);
   if (EQ (safe_codings, XCDR (Vcoding_system_safe_chars)))
     safe_codings = Qt;
   else
@@ -7534,7 +7385,7 @@ syms_of_coding ()
      But don't staticpro it here--that is done in alloc.c.  */
   Qchar_table_extra_slots = intern ("char-table-extra-slots");
   Fput (Qsafe_chars, Qchar_table_extra_slots, make_number (0));
-  Fput (Qchar_coding_system, Qchar_table_extra_slots, make_number (2));
+  Fput (Qchar_coding_system, Qchar_table_extra_slots, make_number (0));
 
   Qvalid_codes = intern ("valid-codes");
   staticpro (&Qvalid_codes);
@@ -7552,7 +7403,6 @@ syms_of_coding ()
   defsubr (&Sdetect_coding_region);
   defsubr (&Sdetect_coding_string);
   defsubr (&Sfind_coding_systems_region_internal);
-  defsubr (&Sfind_coding_systems_region_internal_2);
   defsubr (&Sunencodable_char_position);
   defsubr (&Sdecode_coding_region);
   defsubr (&Sencode_coding_region);
@@ -7774,12 +7624,6 @@ called even if `coding-system-for-write' is non-nil.  The command
   coding_system_require_warning = 0;
 
 
-  DEFVAR_LISP ("char-coding-system-table", &Vchar_coding_system_table,
-               doc: /* Char-table containing safe coding systems of each characters.
-Each element doesn't include such generic coding systems that can
-encode any characters.  They are in the first extra slot.  */);
-  Vchar_coding_system_table = Fmake_char_table (Qchar_coding_system, Qnil);
-
   DEFVAR_BOOL ("inhibit-iso-escape-detection",
                &inhibit_iso_escape_detection,
                doc: /* If non-nil, Emacs ignores ISO2022's escape sequence on code detection.