Date: Mon, 29 Aug 2005 14:04:57 -0700 From: Toby Peterson <toby@apple.com> To: freebsd-bugs@freebsd.org Subject: [PATCH] hexdump -s speedup on /dev Message-ID: <E0887C36-EC54-4A86-A21A-F1EF485EB171@apple.com>
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[-- Attachment #1 --]
This patch vastly increases the performance of hexdump -s <large
offset> on devices. Test:
hexdump -s 100m /dev/ad0
- Toby
[-- Attachment #2 --]
? hexdump
? hexdump.1.gz
? od.1.gz
Index: display.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/hexdump/display.c,v
retrieving revision 1.22
diff -u -r1.22 display.c
--- display.c 4 Aug 2004 02:47:32 -0000 1.22
+++ display.c 29 Aug 2005 20:59:10 -0000
@@ -44,6 +44,7 @@
#include <ctype.h>
#include <err.h>
+#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -384,12 +385,13 @@
return;
}
}
- if (S_ISREG(sb.st_mode)) {
- if (fseeko(stdin, skip, SEEK_SET))
- err(1, "%s", fname);
+ /* try to seek first; fall back on ESPIPE */
+ if (fseeko(stdin, skip, SEEK_SET) == 0) {
address += skip;
skip = 0;
} else {
+ if (errno != ESPIPE)
+ err(1, "%s", fname);
for (cnt = 0; cnt < skip; ++cnt)
if (getchar() == EOF)
break;
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