* 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);
size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
size_t offset, int fillc, size_t bytes);
+/*
+ * Send/recv data from/to iovec buffers directly
+ *
+ * `offset' bytes in the beginning of iovec buffer are skipped and
+ * next `bytes' bytes are used, which must be within data of iovec.
+ *
+ * r = iov_send_recv(sockfd, iov, iovcnt, offset, bytes, true);
+ *
+ * is logically equivalent to
+ *
+ * char *buf = malloc(bytes);
+ * iov_to_buf(iov, iovcnt, offset, buf, bytes);
+ * r = send(sockfd, buf, bytes, 0);
+ * free(buf);
+ *
+ * For iov_send_recv() _whole_ area being sent or received
+ * should be within the iovec, not only beginning of it.
+ */
+ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
+ size_t offset, size_t bytes, bool do_send);
+#define iov_recv(sockfd, iov, iov_cnt, offset, bytes) \
+ iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, false)
+#define iov_send(sockfd, iov, iov_cnt, offset, bytes) \
+ iov_send_recv(sockfd, iov, iov_cnt, offset, bytes, true)
+
/**
* Produce a text hexdump of iovec `iov' with `iov_cnt' number of elements
* in file `fp', prefixing each line with `prefix' and processing not more
*/
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);