iov: Move from hw/ to topdir

The iov functions can be useful to other code as well.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

iov.c

@@ -0,0 +1,70 @@
+/*
+ * Helpers for getting linearized buffers from iov / filling buffers into iovs
+ *
+ * Copyright IBM, Corp. 2007, 2008
+ * Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Author(s):
+ *  Anthony Liguori <aliguori@us.ibm.com>
+ *  Amit Shah <amit.shah@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "iov.h"
+
+size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
+                    const void *buf, size_t size)
+{
+    size_t offset;
+    unsigned int i;
+
+    offset = 0;
+    for (i = 0; offset < size && i < iovcnt; i++) {
+        size_t len;
+
+        len = MIN(iov[i].iov_len, size - offset);
+
+        memcpy(iov[i].iov_base, buf + offset, len);
+        offset += len;
+    }
+    return offset;
+}
+
+size_t iov_to_buf(const struct iovec *iov, const unsigned int iovcnt,
+                  void *buf, size_t offset, size_t size)
+{
+    uint8_t *ptr;
+    size_t iov_off, buf_off;
+    unsigned int i;
+
+    ptr = buf;
+    iov_off = 0;
+    buf_off = 0;
+    for (i = 0; i < iovcnt && size; i++) {
+        if (offset < (iov_off + iov[i].iov_len)) {
+            size_t len = MIN((iov_off + iov[i].iov_len) - offset , size);
+
+            memcpy(ptr + buf_off, iov[i].iov_base + (offset - iov_off), len);
+
+            buf_off += len;
+            offset += len;
+            size -= len;
+        }
+        iov_off += iov[i].iov_len;
+    }
+    return buf_off;
+}
+
+size_t iov_size(const struct iovec *iov, const unsigned int iovcnt)
+{
+    size_t len;
+    unsigned int i;
+
+    len = 0;
+    for (i = 0; i < iovcnt; i++) {
+        len += iov[i].iov_len;
+    }
+    return len;
+}