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.

7 files changed, 33 insertions, 18 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 30af92a57e9..b3125b2c183 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,16 @@
 2011-07-19  Paul Eggert  <eggert@cs.ucla.edu>
 
+	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.
+
 	Use ptrdiff_t for hash table indexes.
 	* category.c (hash_get_category_set):
 	* ccl.c (ccl_driver):
diff --git a/src/character.c b/src/character.c
index c2f23e0d8ec..5e2eccf54db 100644
--- a/src/character.c
+++ b/src/character.c
@@ -423,7 +423,7 @@ lisp_string_width (Lisp_Object string, EMACS_INT precision,
     {
       EMACS_INT chars, bytes, thiswidth;
       Lisp_Object val;
-      int cmp_id;
+      ptrdiff_t cmp_id;
       EMACS_INT ignore, end;
 
       if (find_composition (i, -1, &ignore, &end, &val, string)
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);
 
diff --git a/src/composite.h b/src/composite.h
index 8cedfdbe352..a43e41901ee 100644
--- a/src/composite.h
+++ b/src/composite.h
@@ -204,7 +204,7 @@ struct composition {
    COMPOSITION-ID.  */
 extern struct composition **composition_table;
 /* Number of the currently registered compositions.  */
-extern int n_compositions;
+extern ptrdiff_t n_compositions;
 
 /* Mask bits for CHECK_MASK arg to update_compositions.
    For a change in the region FROM and TO, check compositions ... */
@@ -216,8 +216,8 @@ extern int n_compositions;
 
 extern Lisp_Object Qcomposition;
 extern Lisp_Object composition_hash_table;
-extern int get_composition_id (EMACS_INT, EMACS_INT, EMACS_INT,
-			       Lisp_Object, Lisp_Object);
+extern ptrdiff_t get_composition_id (EMACS_INT, EMACS_INT, EMACS_INT,
+				     Lisp_Object, Lisp_Object);
 extern int find_composition (EMACS_INT, EMACS_INT, EMACS_INT *, EMACS_INT *,
 			     Lisp_Object *, Lisp_Object);
 extern void update_compositions (EMACS_INT, EMACS_INT, int);
@@ -299,7 +299,7 @@ struct face;
 struct font_metrics;
 
 extern Lisp_Object composition_gstring_put_cache (Lisp_Object, EMACS_INT);
-extern Lisp_Object composition_gstring_from_id (int);
+extern Lisp_Object composition_gstring_from_id (ptrdiff_t);
 extern int composition_gstring_p (Lisp_Object);
 extern int composition_gstring_width (Lisp_Object, EMACS_INT, EMACS_INT,
                                       struct font_metrics *);
diff --git a/src/dispextern.h b/src/dispextern.h
index bb4da7d52a8..1d7bf5d53ec 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1240,7 +1240,7 @@ struct glyph_string
   struct composition *cmp;
 
   /* If not negative, this string describes a compos.  */
-  int cmp_id;
+  ptrdiff_t cmp_id;
 
   /* Start and end glyph indices in a glyph-string.  */
   int cmp_from, cmp_to;
@@ -2056,7 +2056,7 @@ struct composition_it
   EMACS_INT stop_pos;
   /* ID number of the composition or glyph-string.  If negative, we
      are not iterating over a composition now.  */
-  int id;
+  ptrdiff_t id;
   /* If non-negative, character that triggers the automatic
      composition at `stop_pos', and this is an automatic composition.
      If negative, this is a static composition.  This is set to -2
diff --git a/src/window.c b/src/window.c
index 3f5a743f5c6..04fea6b9bf6 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5069,7 +5069,7 @@ and redisplay normally--don't erase and redraw the frame.  */)
 	  && (!EQ (Vrecenter_redisplay, Qtty)
 	      || !NILP (Ftty_type (selected_frame))))
 	{
-	  int i;
+	  ptrdiff_t i;
 
 	  /* Invalidate pixel data calculated for all compositions.  */
 	  for (i = 0; i < n_compositions; i++)
diff --git a/src/xdisp.c b/src/xdisp.c
index 43f60abb812..55296db0b8f 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -22002,7 +22002,7 @@ compute_overhangs_and_x (struct glyph_string *s, int x, int backward_p)
   do {									    \
     int face_id = (row)->glyphs[area][START].face_id;			    \
     struct face *base_face = FACE_FROM_ID (f, face_id);			    \
-    int cmp_id = (row)->glyphs[area][START].u.cmp.id;			    \
+    ptrdiff_t cmp_id = (row)->glyphs[area][START].u.cmp.id;		    \
     struct composition *cmp = composition_table[cmp_id];		    \
     XChar2b *char2b;							    \
     struct glyph_string *first_s IF_LINT (= NULL);			    \