From 0dc85aed03239c13b31d2712ef28739879e12336 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Mon, 20 Jul 2015 17:53:30 +0100 Subject: [xfer] Add xfer_check_order() utility function Signed-off-by: Michael Brown --- src/core/xfer.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'src/core/xfer.c') diff --git a/src/core/xfer.c b/src/core/xfer.c index 8d12a9efc..112fee1bf 100644 --- a/src/core/xfer.c +++ b/src/core/xfer.c @@ -359,3 +359,34 @@ int xfer_seek ( struct interface *intf, off_t offset ) { return xfer_deliver ( intf, iobuf, &meta ); } + +/** + * Check that data is delivered strictly in order + * + * @v meta Data transfer metadata + * @v pos Current position + * @v len Length of data + * @ret rc Return status code + */ +int xfer_check_order ( struct xfer_metadata *meta, size_t *pos, size_t len ) { + size_t new_pos; + + /* Allow out-of-order zero-length packets (as used by xfer_seek()) */ + if ( len == 0 ) + return 0; + + /* Calculate position of this delivery */ + new_pos = *pos; + if ( meta->flags & XFER_FL_ABS_OFFSET ) + new_pos = 0; + new_pos += meta->offset; + + /* Fail if delivery position is not equal to current position */ + if ( new_pos != *pos ) + return -EPROTO; + + /* Update current position */ + *pos += len; + + return 0; +} -- cgit v1.2.3-55-g7522