On Mon, 2019-06-24 at 22:37 -0700, Joe Perches wrote:

On Tue, 2019-06-25 at 13:17 +1000, Alastair D'Silva wrote:

quoted

From: Alastair D'Silva <redacted>

With the wider display format, it can become hard to identify how
many
bytes into the line you are looking at.

The patch adds new flags to hex_dump_to_buffer() and
print_hex_dump() to
print vertical lines to separate every N groups of bytes.

eg.
buf:00000000: 454d414e 43415053|4e495f45
00584544  NAMESPAC|E_INDEX.
buf:00000010: 00000000 00000002|00000000
00000000  ........|........

Signed-off-by: Alastair D'Silva <redacted>
---
 include/linux/printk.h |  3 +++
 lib/hexdump.c          | 59 ++++++++++++++++++++++++++++++++++++
------
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h

[]

quoted

@@ -485,6 +485,9 @@ enum {
 
 #define HEXDUMP_ASCII			BIT(0)
 #define HEXDUMP_SUPPRESS_REPEATED	BIT(1)
+#define HEXDUMP_2_GRP_LINES		BIT(2)
+#define HEXDUMP_4_GRP_LINES		BIT(3)
+#define HEXDUMP_8_GRP_LINES		BIT(4)

These aren't really bits as only one value should be set
as 8 overrides 4 and 4 overrides 2.

This should be the other way around, as we should be emitting alternate
seperators based on the smallest grouping (2 implies 4 and 8, and 4
implies 8). I'll fix the logic.

I can't come up with a better way to represent these without making the
API more complex, if you have a suggestion, I'm happy to hear it.

I would also expect this to be a value of 2 in your above
example, rather than 8.  It's described as groups not bytes.

The example is showing a what would normally be a space ' '
separator as a vertical bar '|' every 2nd grouping.

The above example shows a group size of 4 bytes, and
HEXDUMP_2_GRP_LINES set, with 2 groups being 8 bytes.

I'll make that clearer in the commit message.

-- 
Alastair D'Silva           mob: 0423 762 819
skype: alastair_dsilva    
Twitter: @EvilDeece
blog: http://alastair.d-silva.org