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authorMichael S. Tsirkin <mst@redhat.com>2012-09-24 13:02:52 +0200
committerMichael S. Tsirkin <mst@redhat.com>2012-10-29 18:25:22 +0200
commitd336336c8164859e4527cbb9f3df189f8bb406de (patch)
tree535d5bcd4bc99c024dce289d87fa0b1dc5f76809 /iov.c
parente35e23f655fb120a2b4d0695bdee86fafd9caabf (diff)
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iov: add iov_cpy
Add API to copy part of iovec safely. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'iov.c')
-rw-r--r--iov.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/iov.c b/iov.c
index c6a66f0..b7378bf 100644
--- a/iov.c
+++ b/iov.c
@@ -228,3 +228,26 @@ void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
fprintf(fp, "\n");
}
}
+
+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)
+{
+ size_t len;
+ unsigned int i, j;
+ for (i = 0, j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) {
+ if (offset >= iov[i].iov_len) {
+ offset -= iov[i].iov_len;
+ continue;
+ }
+ len = MIN(bytes, iov[i].iov_len - offset);
+
+ dst_iov[j].iov_base = iov[i].iov_base + offset;
+ dst_iov[j].iov_len = len;
+ j++;
+ bytes -= len;
+ offset = 0;
+ }
+ assert(offset == 0);
+ return j;
+}