Use ptrdiff_t for composition IDs.

* character.c (lisp_string_width):
* composite.c (composition_table_size, n_compositions)
(get_composition_id, composition_gstring_from_id):
* dispextern.h (struct glyph_string.cmp_id, struct composition_it.id):
* xdisp.c (BUILD_COMPOSITE_GLYPH_STRING):
* window.c (Frecenter):
Use ptrdiff_t, not int, for composition IDs.
* composite.c (get_composition_id): Check for integer overflow.
* composite.h: Adjust prototypes to match the above changes.

1 files changed, 13 insertions, 9 deletions

diff --git a/src/composite.c b/src/composite.c
index 43041f7b381..b25699b9ff4 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -142,10 +142,10 @@ Lisp_Object Qcomposition;
 struct composition **composition_table;
 
 /* The current size of `composition_table'.  */
-static int composition_table_size;
+static ptrdiff_t composition_table_size;
 
 /* Number of compositions currently made. */
-int n_compositions;
+ptrdiff_t n_compositions;
 
 /* Hash table for compositions.  The key is COMPONENTS-VEC of
    `composition' property.  The value is the corresponding
@@ -172,7 +172,7 @@ Lisp_Object composition_temp;
 
    If the composition is invalid, return -1.  */
 
-int
+ptrdiff_t
 get_composition_id (EMACS_INT charpos, EMACS_INT bytepos, EMACS_INT nchars,
                     Lisp_Object prop, Lisp_Object string)
 {
@@ -260,18 +260,22 @@ get_composition_id (EMACS_INT charpos, EMACS_INT bytepos, EMACS_INT nchars,
   /* Check if we have sufficient memory to store this information.  */
   if (composition_table_size == 0)
     {
-      composition_table_size = 256;
       composition_table
-        = (struct composition **) xmalloc (sizeof (composition_table[0])
-                                           * composition_table_size);
+        = (struct composition **) xmalloc (sizeof (composition_table[0]) * 256);
+      composition_table_size = 256;
     }
   else if (composition_table_size <= n_compositions)
     {
-      composition_table_size += 256;
+      if ((min (MOST_POSITIVE_FIXNUM,
+                min (PTRDIFF_MAX, SIZE_MAX) / sizeof composition_table[0])
+           - 256)
+          < composition_table_size)
+        memory_full (SIZE_MAX);
       composition_table
         = (struct composition **) xrealloc (composition_table,
                                             sizeof (composition_table[0])
-                                            * composition_table_size);
+                                            * (composition_table_size + 256));
+      composition_table_size += 256;
     }
 
   key_contents = XVECTOR (key)->contents;
@@ -691,7 +695,7 @@ composition_gstring_put_cache (Lisp_Object gstring, EMACS_INT len)
 }
 
 Lisp_Object
-composition_gstring_from_id (int id)
+composition_gstring_from_id (ptrdiff_t id)
 {
   struct Lisp_Hash_Table *h = XHASH_TABLE (gstring_hash_table);