* such "large" value is -1 (sinice size_t is unsigned),
* so specifying `-1' as `bytes' means 'up to the end of iovec'.
*/
-size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
+size_t iov_from_buf(const struct iovec *iov, unsigned int iov_cnt,
size_t offset, const void *buf, size_t bytes);
size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
size_t offset, void *buf, size_t bytes);
*/
void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
FILE *fp, const char *prefix, size_t limit);
+
+/*
+ * Partial copy of vector from iov to dst_iov (data is not copied).
+ * dst_iov overlaps iov at a specified offset.
+ * size of dst_iov is at most bytes. dst vector count is returned.
+ */
+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);