qemu iovec: keep track of total size, allow partial copies (Gerd Hoffman)

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6448 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 11 insertions, 4 deletions

diff --git a/cutils.c b/cutils.c
index 80a7a1d8f0..1090aa4c77 100644
--- a/cutils.c
+++ b/cutils.c
@@ -109,6 +109,7 @@ void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint)
     qiov->iov = qemu_malloc(alloc_hint * sizeof(struct iovec));
     qiov->niov = 0;
     qiov->nalloc = alloc_hint;
+    qiov->size = 0;
 }
 
 void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
@@ -119,6 +120,7 @@ void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
     }
     qiov->iov[qiov->niov].iov_base = base;
     qiov->iov[qiov->niov].iov_len = len;
+    qiov->size += len;
     ++qiov->niov;
 }
 
@@ -138,13 +140,18 @@ void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf)
     }
 }
 
-void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf)
+void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf, size_t count)
 {
     const uint8_t *p = (const uint8_t *)buf;
+    size_t copy;
     int i;
 
-    for (i = 0; i < qiov->niov; ++i) {
-        memcpy(qiov->iov[i].iov_base, p, qiov->iov[i].iov_len);
-        p += qiov->iov[i].iov_len;
+    for (i = 0; i < qiov->niov && count; ++i) {
+        copy = count;
+        if (copy > qiov->iov[i].iov_len)
+            copy = qiov->iov[i].iov_len;
+        memcpy(qiov->iov[i].iov_base, p, copy);
+        p     += copy;
+        count -= copy;
     }
 }