Use INT_ADD_WRAPV etc. to check integer overflow

* src/alloc.c (xnmalloc, xnrealloc, xpalloc, Fmake_string):
* src/buffer.c (record_overlay_string, overlay_strings):
* src/casefiddle.c (casify_object):
* src/ccl.c (Fccl_execute_on_string):
* src/character.c (char_width, c_string_width, lisp_string_width)
(count_size_as_multibyte, string_escape_byte8):
* src/coding.c (coding_alloc_by_realloc, produce_chars):
* src/data.c (arith_driver):
* src/dispnew.c (realloc_glyph_pool, init_display):
* src/editfns.c (styled_format):
* src/fns.c (Ffillarray):
* src/ftfont.c (ftfont_shape_by_flt):
* src/gnutls.c (gnutls_hex_string):
* src/gtkutil.c (get_utf8_string):
* src/image.c (x_to_xcolors, x_detect_edges, png_load_body):
* src/keymap.c (Fkey_description):
* src/lisp.h (SAFE_ALLOCA_LISP):
* src/term.c (encode_terminal_code):
* src/tparam.c (tparam1):
* src/xselect.c (x_property_data_to_lisp):
* src/xsmfns.c (smc_save_yourself_CB):
* src/xterm.c (x_term_init):
When checking for integer overflow, prefer INT_MULTIPLY_WRAPV to
more-complicated code involving division and/or
INT_MULTIPLY_OVERFLOW, and similarly for INT_ADD_WRAPV and
subtraction and/or INT_ADD_OVERFLOW.
* src/casefiddle.c (casify_object): Simplify multibyte size check.
* src/character.c: Remove some obsolete ‘#ifdef emacs’s.
* src/data.c (arith_driver): Also check for division overflow,
as that’s now possible given that the accumulator can now contain
any Emacs integer.
* src/lisp.h (lisp_word_count): Remove; no longer used.

1 files changed, 19 insertions, 44 deletions

diff --git a/src/character.c b/src/character.c
index 3e2bf1e70c2..bc2fa4a12da 100644
--- a/src/character.c
+++ b/src/character.c
@@ -25,14 +25,10 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* At first, see the document in `character.h' to understand the code
    in this file.  */
 
-#ifdef emacs
 #include <config.h>
-#endif
 
 #include <stdio.h>
 
-#ifdef emacs
-
 #include <sys/types.h>
 #include <intprops.h>
 #include "lisp.h"
@@ -41,12 +37,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "composite.h"
 #include "disptab.h"
 
-#else  /* not emacs */
-
-#include "mulelib.h"
-
-#endif /* emacs */
-
 /* Char-table of information about which character to unify to which
    Unicode character.  Mainly used by the macro MAYBE_UNIFY_CHAR.  */
 Lisp_Object Vchar_unify_table;
@@ -302,9 +292,8 @@ char_width (int c, struct Lisp_Char_Table *dp)
             if (CHARACTERP (ch))
               {
                 int w = CHAR_WIDTH (XFASTINT (ch));
-                if (INT_ADD_OVERFLOW (width, w))
+                if (INT_ADD_WRAPV (width, w, &width))
                   string_overflow ();
-                width += w;
               }
           }
     }
@@ -349,20 +338,16 @@ c_string_width (const unsigned char *str, ptrdiff_t len, int precision,
       int c = STRING_CHAR_AND_LENGTH (str + i_byte, bytes);
       ptrdiff_t thiswidth = char_width (c, dp);
 
-      if (precision <= 0)
-        {
-          if (INT_ADD_OVERFLOW (width, thiswidth))
-            string_overflow ();
-        }
-      else if (precision - width < thiswidth)
+      if (0 < precision && precision - width < thiswidth)
         {
           *nchars = i;
           *nbytes = i_byte;
           return width;
         }
+      if (INT_ADD_WRAPV (thiswidth, width, &width))
+        string_overflow ();
       i++;
       i_byte += bytes;
-      width += thiswidth;
   }
 
   if (precision > 0)
@@ -436,22 +421,16 @@ lisp_string_width (Lisp_Object string, ptrdiff_t precision,
           thiswidth = char_width (c, dp);
         }
 
-      if (precision <= 0)
-        {
-#ifdef emacs
-          if (INT_ADD_OVERFLOW (width, thiswidth))
-            string_overflow ();
-#endif
-        }
-      else if (precision - width < thiswidth)
+      if (0 < precision && precision - width < thiswidth)
         {
           *nchars = i;
           *nbytes = i_byte;
           return width;
         }
+      if (INT_ADD_WRAPV (thiswidth, width, &width))
+        string_overflow ();
       i += chars;
       i_byte += bytes;
-      width += thiswidth;
     }
 
   if (precision > 0)
@@ -657,9 +636,8 @@ count_size_as_multibyte (const unsigned char *str, ptrdiff_t len)
   for (bytes = 0; str < endp; str++)
     {
       int n = *str < 0x80 ? 1 : 2;
-      if (INT_ADD_OVERFLOW (bytes, n))
+      if (INT_ADD_WRAPV (bytes, n, &bytes))
         string_overflow ();
-      bytes += n;
     }
   return bytes;
 }
@@ -795,6 +773,7 @@ string_escape_byte8 (Lisp_Object string)
   ptrdiff_t nbytes = SBYTES (string);
   bool multibyte = STRING_MULTIBYTE (string);
   ptrdiff_t byte8_count;
+  ptrdiff_t thrice_byte8_count, uninit_nchars, uninit_nbytes;
   const unsigned char *src, *src_end;
   unsigned char *dst;
   Lisp_Object val;
@@ -808,23 +787,23 @@ string_escape_byte8 (Lisp_Object string)
   if (byte8_count == 0)
     return string;
 
+  if (INT_MULTIPLY_WRAPV (byte8_count, 3, &thrice_byte8_count))
+    string_overflow ();
+
   if (multibyte)
     {
-      if ((MOST_POSITIVE_FIXNUM - nchars) / 3 < byte8_count
-          || (STRING_BYTES_BOUND - nbytes) / 2 < byte8_count)
-        string_overflow ();
-
       /* Convert 2-byte sequence of byte8 chars to 4-byte octal.  */
-      val = make_uninit_multibyte_string (nchars + byte8_count * 3,
-                                          nbytes + byte8_count * 2);
+      if (INT_ADD_WRAPV (nchars, thrice_byte8_count, &uninit_nchars)
+          || INT_ADD_WRAPV (nbytes, 2 * byte8_count, &uninit_nbytes))
+        string_overflow ();
+      val = make_uninit_multibyte_string (uninit_nchars, uninit_nbytes);
     }
   else
     {
-      if ((STRING_BYTES_BOUND - nbytes) / 3 < byte8_count)
-        string_overflow ();
-
       /* Convert 1-byte sequence of byte8 chars to 4-byte octal.  */
-      val = make_uninit_string (nbytes + byte8_count * 3);
+      if (INT_ADD_WRAPV (thrice_byte8_count, nbytes, &uninit_nbytes))
+        string_overflow ();
+      val = make_uninit_string (uninit_nbytes);
     }
 
   src = SDATA (string);
@@ -981,8 +960,6 @@ character is not ASCII nor 8-bit character, an error is signaled.  */)
   return make_number (c);
 }
 
-#ifdef emacs
-
 /* Return true if C is an alphabetic character.  */
 bool
 alphabeticp (int c)
@@ -1131,5 +1108,3 @@ See The Unicode Standard for the meaning of those values.  */);
   /* The correct char-table is setup in characters.el.  */
   Vunicode_category_table = Qnil;
 }
-
-#endif /* emacs */