made the progress meter display not overflow even if _very_ large files

are transfered. The maximum size we support now is 8 exabytes, which equals
to 8192 petabytes...

lib/progress.c

@@ -68,8 +68,10 @@ static void time2str(char *r, long t)
 static char *max5data(curl_off_t bytes, char *max5)
 {
 #define ONE_KILOBYTE 1024
-#define ONE_MEGABYTE (1024*1024)
-#define ONE_GIGABYTE (1024*1024*1024)
+#define ONE_MEGABYTE (1024* ONE_KILOBYTE)
+#define ONE_GIGABYTE (1024* ONE_MEGABYTE)
+#define ONE_TERRABYTE ((curl_off_t)1024* ONE_GIGABYTE)
+#define ONE_PETABYTE ((curl_off_t)1024* ONE_TERRABYTE)
 
   if(bytes < 100000) {
     sprintf(max5, "%5" FORMAT_OFF_T, bytes);
@@ -84,14 +86,31 @@ static char *max5data(curl_off_t bytes, char *max5)
             (int)(bytes%ONE_MEGABYTE)/(ONE_MEGABYTE/10) );
   }
 #if SIZEOF_CURL_OFF_T > 4
-  else if(bytes < ((curl_off_t)10000*ONE_MEGABYTE)) {
+  else if(bytes < ( (curl_off_t)10000*ONE_MEGABYTE))
+    /* 'XXXXM' is good until we're at 10000MB or above */
     sprintf(max5, "%4" FORMAT_OFF_T "M", (curl_off_t)(bytes/ONE_MEGABYTE));
-  }
-  else
-    /* 10000 MB - 8589934587 GB !! */
+
+  else if(bytes < (curl_off_t)100*ONE_GIGABYTE)
+    /* 10000 MB - 100 GB, we show it as XX.XG */
     sprintf(max5, "%2d.%0dG",
             (int)(bytes/ONE_GIGABYTE),
             (int)(bytes%ONE_GIGABYTE)/(ONE_GIGABYTE/10) );
+
+  else if(bytes < (curl_off_t)10000 * ONE_GIGABYTE)
+    /* up to 10000GB, display without decimal: XXXXG */
+    sprintf(max5, "%4dG", (int)(bytes/ONE_GIGABYTE));
+
+  else if(bytes < (curl_off_t)10000 * ONE_TERRABYTE)
+    /* up to 10000TB, display without decimal: XXXXT */
+    sprintf(max5, "%4dT", (int)(bytes/ONE_TERRABYTE));
+  else {
+    /* up to 10000PB, display without decimal: XXXXP */
+    sprintf(max5, "%4dP", (int)(bytes/ONE_PETABYTE));
+
+    /* 16384 petabytes (16 exabytes) is maximum a 64 bit number can hold,
+       but this type is signed so 8192PB will be max.*/
+  }
+
 #else
   else
     sprintf(max5, "%4" FORMAT_OFF_T "M", (curl_off_t)(bytes/ONE_MEGABYTE));