* coding.c (ALLOC_CONVERSION_WORK_AREA): Prefer ptrdiff_t to int and

so avoid integer overflow if decoded gap size exceeds INT_MAX bytes.

2 files changed, 7 insertions, 7 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 10984d5ce25..fa79ac43bdf 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -15,6 +15,9 @@
         * xfont.c (xfont_open):
         * xftfont.c (xftfont_open): All users changed.
 
+        * coding.c (ALLOC_CONVERSION_WORK_AREA): Prefer ptrdiff_t to int and
+        so avoid integer overflow if decoded gap size exceeds INT_MAX bytes.
+
 2014-07-09  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (move_it_to): Adjust calculation of line_start_x to what
diff --git a/src/coding.c b/src/coding.c
index d4c468cfbbf..5e7a676aecd 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -7273,15 +7273,12 @@ produce_charset (struct coding_system *coding, int *charbuf, ptrdiff_t pos)
 
 #define ALLOC_CONVERSION_WORK_AREA(coding, size)                \
   do {                                                          \
-    int units = (size) + MAX_CHARBUF_EXTRA_SIZE;                \
-                                                                \
-    if (units > MAX_CHARBUF_SIZE)                               \
-      units = MAX_CHARBUF_SIZE;                                 \
-    coding->charbuf = SAFE_ALLOCA ((units) * sizeof (int));     \
-    coding->charbuf_size = (units);                             \
+    ptrdiff_t units = min ((size) + MAX_CHARBUF_EXTRA_SIZE,     \
+                           MAX_CHARBUF_SIZE);                   \
+    coding->charbuf = SAFE_ALLOCA (units * sizeof (int));       \
+    coding->charbuf_size = units;                               \
   } while (0)
 
-
 static void
 produce_annotation (struct coding_system *coding, ptrdiff_t pos)
 {