From de00a933e4b35b42398582eaba58531e5fdd46ca Mon Sep 17 00:00:00 2001
From: Paul Eggert
Date: Fri, 27 Mar 2020 00:58:31 -0700
Subject: Treat out-of-range positions consistently

If a position argument to get-byte etc. is an out-of-range integer,
treat it the same regardless of whether it is a fixnum or a bignum.
* src/buffer.c (fix_position): New function.
* src/buffer.c (validate_region):
* src/character.c (Fget_byte):
* src/coding.c (Ffind_coding_systems_region_internal)
(Fcheck_coding_systems_region):
* src/composite.c (Ffind_composition_internal):
* src/editfns.c (Fposition_bytes, Fchar_after, Fchar_before)
(Finsert_buffer_substring, Fcompare_buffer_substrings)
(Fnarrow_to_region):
* src/fns.c (Fsecure_hash_algorithms):
* src/font.c (Finternal_char_font, Ffont_at):
* src/fringe.c (Ffringe_bitmaps_at_pos):
* src/search.c (search_command):
* src/textprop.c (get_char_property_and_overlay):
* src/window.c (Fpos_visible_in_window_p):
* src/xdisp.c (Fwindow_text_pixel_size):
Use it instead of CHECK_FIXNUM_COERCE_MARKER, so that
the code is simpler and treats bignums consistently with fixnums.
* src/buffer.h (CHECK_FIXNUM_COERCE_MARKER): Define here
rather than in lisp.h, and reimplement in terms of fix_position
so that it treats bignums consistently with fixnums.
* src/lisp.h (CHECK_FIXNUM_COERCE_MARKER): Move to buffer.h.
* src/textprop.c (validate_interval_range): Signal with original
bounds rather than modified ones.
---
 src/buffer.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

(limited to 'src/buffer.c')

diff --git a/src/buffer.c b/src/buffer.c
index cc7d4e4817c..70598a7a22a 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -131,6 +131,23 @@ CHECK_OVERLAY (Lisp_Object x)
   CHECK_TYPE (OVERLAYP (x), Qoverlayp, x);
 }
 
+/* Convert the position POS to an EMACS_INT that fits in a fixnum.
+   Yield POS's value if POS is already a fixnum, POS's marker position
+   if POS is a marker, and MOST_NEGATIVE_FIXNUM or
+   MOST_POSITIVE_FIXNUM if POS is a negative or positive bignum.
+   Signal an error if POS is not of the proper form.  */
+
+EMACS_INT
+fix_position (Lisp_Object pos)
+{
+  if (FIXNUMP (pos))
+    return XFIXNUM (pos);
+  if (MARKERP (pos))
+    return marker_position (pos);
+  CHECK_TYPE (BIGNUMP (pos), Qinteger_or_marker_p, pos);
+  return !NILP (Fnatnump (pos)) ? MOST_POSITIVE_FIXNUM : MOST_NEGATIVE_FIXNUM;
+}
+
 /* These setters are used only in this file, so they can be private.
    The public setters are inline functions defined in buffer.h.  */
 static void
@@ -2257,19 +2274,20 @@ so the buffer is truly empty after this.  */)
 }
 
 void
-validate_region (register Lisp_Object *b, register Lisp_Object *e)
+validate_region (Lisp_Object *b, Lisp_Object *e)
 {
-  CHECK_FIXNUM_COERCE_MARKER (*b);
-  CHECK_FIXNUM_COERCE_MARKER (*e);
+  EMACS_INT beg = fix_position (*b), end = fix_position (*e);
 
-  if (XFIXNUM (*b) > XFIXNUM (*e))
+  if (end < beg)
     {
-      Lisp_Object tem;
-      tem = *b;  *b = *e;  *e = tem;
+      EMACS_INT tem = beg;  beg = end;  end = tem;
     }
 
-  if (! (BEGV <= XFIXNUM (*b) && XFIXNUM (*e) <= ZV))
+  if (! (BEGV <= beg && end <= ZV))
     args_out_of_range_3 (Fcurrent_buffer (), *b, *e);
+
+  *b = make_fixnum (beg);
+  *e = make_fixnum (end);
 }
 
 /* Advance BYTE_POS up to a character boundary
-- 
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