Adjust in response to jan.h.d's comments.

See, for example <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=9196#26>.

1 files changed, 17 insertions, 23 deletions

diff --git a/src/ccl.c b/src/ccl.c
index 0a9b3d90708..dc0adae6877 100644
--- a/src/ccl.c
+++ b/src/ccl.c
@@ -2067,6 +2067,7 @@ usage: (ccl-execute-on-string CCL-PROGRAM STATUS STRING &optional CONTINUE UNIBY
 #define CCL_EXECUTE_BUF_SIZE 1024
   int source[CCL_EXECUTE_BUF_SIZE], destination[CCL_EXECUTE_BUF_SIZE];
   ptrdiff_t consumed_chars, consumed_bytes, produced_chars;
+  int buf_magnification;
 
   if (setup_ccl_program (&ccl, ccl_prog) < 0)
     error ("Invalid CCL program");
@@ -2093,9 +2094,9 @@ usage: (ccl-execute-on-string CCL-PROGRAM STATUS STRING &optional CONTINUE UNIBY
         ccl.ic = i;
     }
 
-  if (((min (PTRDIFF_MAX, SIZE_MAX) - 256)
-       / (ccl.buf_magnification ? ccl.buf_magnification : 1))
-      < str_bytes)
+  buf_magnification = ccl.buf_magnification ? ccl.buf_magnification : 1;
+
+  if ((min (PTRDIFF_MAX, SIZE_MAX) - 256) / buf_magnification < str_bytes)
     memory_full (SIZE_MAX);
   outbufsize = (ccl.buf_magnification
                 ? str_bytes * ccl.buf_magnification + 256
@@ -2131,20 +2132,18 @@ usage: (ccl-execute-on-string CCL-PROGRAM STATUS STRING &optional CONTINUE UNIBY
           produced_chars += ccl.produced;
           if (NILP (unibyte_p))
             {
+              /* FIXME: Surely this should be buf_magnification instead.
+                 MAX_MULTIBYTE_LENGTH overestimates the storage needed.  */
+              int magnification = MAX_MULTIBYTE_LENGTH;
+
               ptrdiff_t offset = outp - outbuf;
-              if ((outbufsize - offset) / MAX_MULTIBYTE_LENGTH < ccl.produced)
+              ptrdiff_t shortfall;
+              if (INT_MULTIPLY_OVERFLOW (ccl.produced, magnification))
+                memory_full (SIZE_MAX);
+              shortfall = ccl.produced * magnification - (outbufsize - offset);
+              if (0 < shortfall)
                 {
-                  ptrdiff_t produced;
-                  if (((min (PTRDIFF_MAX, SIZE_MAX) - outbufsize)
-                       / MAX_MULTIBYTE_LENGTH)
-                      < ccl.produced)
-                    {
-                      xfree (outbuf);
-                      memory_full (SIZE_MAX);
-                    }
-                  produced = ccl.produced;
-                  outbufsize += MAX_MULTIBYTE_LENGTH * produced;
-                  outbuf = (unsigned char *) xrealloc (outbuf, outbufsize);
+                  outbuf = xpalloc (outbuf, &outbufsize, shortfall, -1, 1);
                   outp = outbuf + offset;
                 }
               for (j = 0; j < ccl.produced; j++)
@@ -2153,15 +2152,10 @@ usage: (ccl-execute-on-string CCL-PROGRAM STATUS STRING &optional CONTINUE UNIBY
           else
             {
               ptrdiff_t offset = outp - outbuf;
-              if (outbufsize - offset < ccl.produced)
+              ptrdiff_t shortfall = ccl.produced - (outbufsize - offset);
+              if (0 < shortfall)
                 {
-                  if (min (PTRDIFF_MAX, SIZE_MAX) - outbufsize < ccl.produced)
-                    {
-                      xfree (outbuf);
-                      memory_full (SIZE_MAX);
-                    }
-                  outbufsize += ccl.produced;
-                  outbuf = (unsigned char *) xrealloc (outbuf, outbufsize);
+                  outbuf = xpalloc (outbuf, &outbufsize, shortfall, -1, 1);
                   outp = outbuf + offset;
                 }
               for (j = 0; j < ccl.produced; j++)