3 files changed, 43 insertions, 11 deletions

diff --git a/src/core/aio.c b/src/core/aio.c
index c6e0ed97..a036a606 100644
--- a/src/core/aio.c
+++ b/src/core/aio.c
@@ -66,8 +66,10 @@ nni_aio_init(nni_aio **aiop, nni_cb cb, void *arg)
 	}
 	memset(aio, 0, sizeof(*aio));
 	nni_cv_init(&aio->a_cv, &nni_aio_lk);
-	aio->a_expire  = NNI_TIME_NEVER;
-	aio->a_timeout = NNG_DURATION_INFINITE;
+	aio->a_expire    = NNI_TIME_NEVER;
+	aio->a_timeout   = NNG_DURATION_INFINITE;
+	aio->a_iov       = aio->a_iovinl;
+	aio->a_niovalloc = 0;
 	if (arg == NULL) {
 		arg = aio;
 	}
@@ -85,10 +87,34 @@ nni_aio_fini(nni_aio *aio)
 		// At this point the AIO is done.
 		nni_cv_fini(&aio->a_cv);
 
+		if (aio->a_niovalloc > 0) {
+			NNI_FREE_STRUCTS(aio->a_iov, aio->a_niovalloc);
+		}
+
 		NNI_FREE_STRUCT(aio);
 	}
 }
 
+int
+nni_aio_set_iov(nni_aio *aio, int niov, nng_iov *iov)
+{
+	if ((niov > 4) && (niov > aio->a_niovalloc)) {
+		nni_iov *newiov = NNI_ALLOC_STRUCTS(newiov, niov);
+		if (newiov == NULL) {
+			return (NNG_ENOMEM);
+		}
+		if (aio->a_niovalloc > 0) {
+			NNI_FREE_STRUCTS(aio->a_iov, aio->a_niovalloc);
+		}
+		aio->a_iov       = newiov;
+		aio->a_niovalloc = niov;
+	}
+
+	memcpy(aio->a_iov, iov, niov * sizeof(nng_iov));
+	aio->a_niov = niov;
+	return (0);
+}
+
 void
 nni_aio_fini_cb(nni_aio *aio)
 {
diff --git a/src/core/aio.h b/src/core/aio.h
index b5db29c9..33fe07cb 100644
--- a/src/core/aio.h
+++ b/src/core/aio.h
@@ -39,8 +39,10 @@ struct nni_aio {
 	nni_task a_task;
 
 	// Read/write operations.
-	nni_iov a_iov[4];
-	int     a_niov;
+	nni_iov *a_iov;
+	int      a_niov;
+	nni_iov  a_iovinl[4]; // inline IOVs - when the IOV list is short
+	int      a_niovalloc; // number of allocated IOVs
 
 	// Message operations.
 	nni_msg *a_msg;
@@ -126,6 +128,11 @@ extern void nni_aio_set_output(nni_aio *, int, void *);
 // nni_get_output returns an output previously stored on the AIO.
 extern void *nni_aio_get_output(nni_aio *, int);
 
+// nni_aio_set_iov sets an IOV (scatter/gather vector) on the AIO.
+// Up to 4 may be set without any possibility of failure, more than that
+// may require an allocation and hence fail due to NNG_ENOMEM.
+extern int nni_aio_set_iov(nni_aio *, int, nng_iov *);
+
 // XXX: These should be refactored in terms of generic inputs and outputs.
 extern void     nni_aio_set_msg(nni_aio *, nni_msg *);
 extern nni_msg *nni_aio_get_msg(nni_aio *);
diff --git a/src/core/defs.h b/src/core/defs.h
index cecb4825..fbf074b4 100644
--- a/src/core/defs.h
+++ b/src/core/defs.h
@@ -1,5 +1,6 @@
 //
-// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitoar.com>
 //
 // This software is supplied under the terms of the MIT License, a
 // copy of which should be located in the distribution where this
@@ -34,6 +35,7 @@ typedef struct nng_sockaddr nni_sockaddr;
 typedef struct nng_event    nni_event;
 typedef struct nng_notify   nni_notify;
 typedef struct nng_url      nni_url;
+typedef struct nng_iov      nni_iov;
 
 // These are our own names.
 typedef struct nni_socket           nni_sock;
@@ -64,12 +66,6 @@ typedef struct nni_aio nni_aio;
 
 typedef void (*nni_cb)(void *);
 
-// Used by transports for scatter gather I/O.
-typedef struct {
-	uint8_t *iov_buf;
-	size_t   iov_len;
-} nni_iov;
-
 // Notify descriptor.
 typedef struct {
 	int sn_wfd; // written to in order to flag an event
@@ -134,6 +130,9 @@ typedef struct {
 	    (((uint64_t)((uint8_t)(ptr)[6])) << 8) +  \
 	    (((uint64_t)(uint8_t)(ptr)[7]))
 
+// This increments a pointer a fixed number of byte cells.
+#define NNI_INCPTR(ptr, n) ((ptr) = (void *) ((char *) (ptr) + (n)))
+
 // A few assorted other items.
 #define NNI_FLAG_IPV4ONLY 1