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-rw-r--r--iov.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/iov.c b/iov.c
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+++ b/iov.c
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+/*
+ * 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;
+}