[2/2] incubator-mynewt-newt git commit: more documentation for the first packet

[pa...@apache.org]

more documentation for the first packet


Project: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-newt/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-newt/commit/f544ec6f
Tree: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-newt/tree/f544ec6f
Diff: http://git-wip-us.apache.org/repos/asf/incubator-mynewt-newt/diff/f544ec6f

Branch: refs/heads/develop
Commit: f544ec6fb3d45e0a685541952c70eabf949c26ff
Parents: dba476c
Author: paulfdietrich <pa...@yahoo.com>
Authored: Tue Oct 18 15:48:35 2016 -0700
Committer: paulfdietrich <pa...@yahoo.com>
Committed: Tue Oct 18 15:48:35 2016 -0700

----------------------------------------------------------------------
 newtmgr/cli/image.go | 11 +++++++++++
 1 file changed, 11 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/incubator-mynewt-newt/blob/f544ec6f/newtmgr/cli/image.go
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diff --git a/newtmgr/cli/image.go b/newtmgr/cli/image.go
index c2e94ed..7bcb879 100644
--- a/newtmgr/cli/image.go
+++ b/newtmgr/cli/image.go
@@ -295,6 +295,17 @@ func imageUploadCmd(cmd *cobra.Command, args []string) {
 		if currOff == 0 {
 			/* we need extra space to encode the image size */
 			if blockSz > (mtu - 8) {
+				/*
+				 * to encode the image size, we write clen=val in CBOR.
+				 * From below (for up to 2G images, you can see that it
+				 * will take up to 9 bytes.  (starts at 63.. ends at e8)
+				 * 00000040  7d c4 00 00 7d c4 00 00  63 6c 65 6e 1a 00 01 5d  |}...}...clen...]|
+				 * 00000050  e8 63 6f 66 66 00                                 |.coff.|
+				 * However, since the offset is zero, we will use less
+				 * bytes (we budgeted for 5 bytes but will only use 1
+				 */
+
+				/* to make these powers of 2, just go with 8 bytes */
 				blockSz = mtu - 8
 			}
 		}