[PATCH 04/11] sio: fix passing negative size_t to sio_add_to_iov
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Fri Nov 30 18:39:36 MSK 2018
sio_add_to_iov moves struct iov position on a
specified offset, positive or negative. But its offset
argument has size_t type, which is unsigned. Make it
be ssize_t.
This worked before thanks to how negative numbers are
stored. For example, consider
uint8_t value = 100;
uint8_t offset = -5;
Value is stored as 0110 0100.
Offset is stored as 1111 1011. (Yes, 1011, not 1010).
Sum of the values above is 0001 0101 1111 - first quad
overflows and is truncated, so the result is
0101 1111 = 95 - correct.
---
src/sio.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/sio.h b/src/sio.h
index ab0a243cd..ff383aa36 100644
--- a/src/sio.h
+++ b/src/sio.h
@@ -84,7 +84,7 @@ sio_move_iov(struct iovec *iov, size_t nwr, size_t *iov_len)
* to adjust to a partial write.
*/
static inline void
-sio_add_to_iov(struct iovec *iov, size_t size)
+sio_add_to_iov(struct iovec *iov, ssize_t size)
{
iov->iov_len += size;
iov->iov_base = (char *) iov->iov_base - size;
--
2.17.2 (Apple Git-113)
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