1 files changed, 15 insertions, 18 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 6027ccdda9f..fe198b0770a 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -218,9 +218,10 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
   int fd[2];
   int filefd;
   register int pid;
-  char buf[16384];
-  char *bufptr = buf;
-  int bufsize = sizeof buf;
+#define CALLPROC_BUFFER_SIZE_MIN (16 * 1024)
+#define CALLPROC_BUFFER_SIZE_MAX (4 * CALLPROC_BUFFER_SIZE_MIN)
+  char buf[CALLPROC_BUFFER_SIZE_MAX];
+  int bufsize = CALLPROC_BUFFER_SIZE_MIN;
   int count = SPECPDL_INDEX ();
 
   register const unsigned char **new_argv
@@ -765,7 +766,7 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
         nread = carryover;
         while (nread < bufsize - 1024)
           {
-            int this_read = emacs_read (fd[0], bufptr + nread,
+            int this_read = emacs_read (fd[0], buf + nread,
                                         bufsize - nread);
 
             if (this_read < 0)
@@ -790,7 +791,7 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
         if (!NILP (buffer))
           {
             if (! CODING_MAY_REQUIRE_DECODING (&process_coding))
-              insert_1_both (bufptr, nread, nread, 0, 1, 0);
+              insert_1_both (buf, nread, nread, 0, 1, 0);
             else
               {                 /* We have to decode the input.  */
                 int size;
@@ -807,7 +808,7 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
                    requires text-encoding detection.  */
                 if (process_coding.type == coding_type_undecided)
                   {
-                    detect_coding (&process_coding, bufptr, nread);
+                    detect_coding (&process_coding, buf, nread);
                     if (process_coding.composing != COMPOSITION_DISABLED)
                       /* We have not yet allocated the composition
                          data because the coding type was undecided.  */
@@ -816,7 +817,7 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
                 if (process_coding.cmp_data)
                   process_coding.cmp_data->char_offset = PT;
 
-                decode_coding (&process_coding, bufptr, decoding_buf,
+                decode_coding (&process_coding, buf, decoding_buf,
                                nread, size);
 
                 if (display_on_the_fly
@@ -905,7 +906,7 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
                 if (carryover > 0)
                   /* As CARRYOVER should not be that large, we had
                      better avoid overhead of bcopy.  */
-                  BCOPY_SHORT (bufptr + process_coding.consumed, bufptr,
+                  BCOPY_SHORT (buf + process_coding.consumed, buf,
                                carryover);
                 if (process_coding.result == CODING_FINISH_INSUFFICIENT_CMP)
                   {
@@ -922,17 +923,13 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
         if (process_coding.mode & CODING_MODE_LAST_BLOCK)
           break;
 
+#if (CALLPROC_BUFFER_SIZE_MIN != CALLPROC_BUFFER_SIZE_MAX)
         /* Make the buffer bigger as we continue to read more data,
-           but not past 64k.  */
-        if (bufsize < 64 * 1024 && total_read > 32 * bufsize)
-          {
-            char *tempptr;
-            bufsize *= 2;
-
-            tempptr = (char *) alloca (bufsize);
-            bcopy (bufptr, tempptr, bufsize / 2);
-            bufptr = tempptr;
-          }
+           but not past CALLPROC_BUFFER_SIZE_MAX.  */
+        if (bufsize < CALLPROC_BUFFER_SIZE_MAX && total_read > 32 * bufsize)
+          if ((bufsize *= 2) > CALLPROC_BUFFER_SIZE_MAX)
+            bufsize = CALLPROC_BUFFER_SIZE_MAX;
+#endif
 
         if (display_p)
           {