From d02776350d9c76348988fc9e58a64a4f6b1a9f61 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 21 Nov 2012 17:41:10 +0100 Subject: iov: add iov_discard_front/back() to remove data The iov_discard_front/back() functions remove data from the front or back of the vector. This is useful when peeling off header/footer structs. Signed-off-by: Stefan Hajnoczi --- include/qemu/iov.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/qemu') diff --git a/include/qemu/iov.h b/include/qemu/iov.h index d06f8b9..68d25f2 100644 --- a/include/qemu/iov.h +++ b/include/qemu/iov.h @@ -99,4 +99,17 @@ unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, const struct iovec *iov, unsigned int iov_cnt, size_t offset, size_t bytes); +/* + * Remove a given number of bytes from the front or back of a vector. + * This may update iov and/or iov_cnt to exclude iovec elements that are + * no longer required. + * + * The number of bytes actually discarded is returned. This number may be + * smaller than requested if the vector is too small. + */ +size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, + size_t bytes); +size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, + size_t bytes); + #endif -- cgit v1.1