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allow print_size to print large numbers on 32-bit systems

PATCH Superseded Timur Tabi 1 participant 1 message Apr 12, 2010

v4 of 6 Superseded Latest is v6 →

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Timur Tabi

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PATCH v4 1/1 allow print_size to print large numbers on 32-bit systems

Modify print_size() so that it can accept numbers larger than 4GB on 32-bit systems.

Add support for display terabyte, petabyte, and exabyte sizes. Change the output to use International Electrotechnical Commission binary prefix standard.

---

optimized the loop. If I had a log-base-10 function, I could eliminate it completely, but it appears only ppc has __ilog2.

 lib_generic/display_options.c |   29 +++++++++++++++++------------
 1 files changed, 17 insertions(+), 12 deletions(-)
lib_generic/display_options.c +18 -13
index da17a62..86df05d 100644
@@ -39,25 +39,30 @@ int display_options (void)
 }
 
 /*
- * print sizes as "xxx kB", "xxx.y kB", "xxx MB", "xxx.y MB",
- * xxx GB, or xxx.y GB as needed; allow for optional trailing string
+ * print sizes as "xxx KiB", "xxx.y KiB", "xxx MiB", "xxx.y MiB",
+ * xxx GiB, xxx.y GiB, etc as needed; allow for optional trailing string
  * (like "\n")
  */
 void print_size(unsigned long long size, const char *s)
 {
 	unsigned long m = 0, n;
-	unsigned long long d = 1 << 30; 	/* 1 GB */
-	char  c = 'G';
-
-	if (size < d) {			/* try MB */
-		c = 'M';
-		d = 1 << 20;
-		if (size < d) {		/* print in kB */
-			c = 'k';
-			d = 1 << 10;
+	static const char names[] = {'E', 'P', 'T', 'G', 'M', 'K'};
+	unsigned long long d = 1ULL << (10 * ARRAY_SIZE(names));
+	char c = 0;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(names); i++, d >>= 10) {
+		if (size >= d) {
+			c = names[i];
+			break;
 		}
 	}
 
+	if (!c) {
+		printf("%llu Bytes%s", size, s);
+		return;
+	}
+
 	n = size / d;
 
 	/* If there's a remainder, deal with it */
@@ -70,11 +75,11 @@ void print_size(unsigned long long size, const char *s)
 		}
 	}
 
-	printf ("%2ld", n);
+	printf ("%lu", n);
 	if (m) {
 		printf (".%ld", m);
 	}
-	printf (" %cB%s", c, s);
+	printf (" %ciB%s", c, s);
 }
 
 /*
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