Am 08.12.2021 um 11:19 schrieb Corinna Vinschen:
On Dec 8 01:43, Mark Geisert wrote:
Takashi Yano wrote:
[...]
I think the following patch makes the intent clearer.
What do you think?
From d0aee9af225384a24ac6301f987ce2e94f262500 Mon Sep 17 00:00:00 2001
From: Takashi Yano <takashi.y...@nifty.ne.jp>
Date: Wed, 8 Dec 2021 17:06:03 +0900
Subject: [PATCH] Cygwin: clipboard: Make intent of the code clearer.
---
winsup/cygwin/fhandler_clipboard.cc | 4 ++--
winsup/cygwin/include/sys/clipboard.h | 1 +
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/winsup/cygwin/fhandler_clipboard.cc
b/winsup/cygwin/fhandler_clipboard.cc
index 05f54ffb3..65a3cad97 100644
--- a/winsup/cygwin/fhandler_clipboard.cc
+++ b/winsup/cygwin/fhandler_clipboard.cc
@@ -76,7 +76,7 @@ fhandler_dev_clipboard::set_clipboard (const void *buf,
size_t len)
clipbuf->cb_sec = clipbuf->ts.tv_sec;
#endif
clipbuf->cb_size = len;
- memcpy (&clipbuf[1], buf, len); // append user-supplied data
+ memcpy (clipbuf->data, buf, len); // append user-supplied data
GlobalUnlock (hmem);
EmptyClipboard ();
@@ -229,7 +229,7 @@ fhandler_dev_clipboard::read (void *ptr, size_t& len)
if (pos < (off_t) clipbuf->cb_size)
{
ret = (len > (clipbuf->cb_size - pos)) ? clipbuf->cb_size - pos : len;
- memcpy (ptr, (char *) (clipbuf + 1) + pos, ret);
+ memcpy (ptr, clipbuf->data + pos, ret);
pos += ret;
}
}
diff --git a/winsup/cygwin/include/sys/clipboard.h
b/winsup/cygwin/include/sys/clipboard.h
index 4c00c8ea1..b2544be85 100644
--- a/winsup/cygwin/include/sys/clipboard.h
+++ b/winsup/cygwin/include/sys/clipboard.h
@@ -44,6 +44,7 @@ typedef struct
};
};
uint64_t cb_size; // 8 bytes everywhere
+ char data[];
} cygcb_t;
#endif
Sigh. I guess it's not possible to keep rid of a data item like I'd hoped.
At least "data[]" is cleaner than the historical "data[1]" here. If you
call the item cb_data I can live with it.
Thanks all for the discussion.
sometype *ptr;
ptr = (sometype *) somebuffer;
do_something (ptr + 1);
is a perfectly valid and perfectly readable thing, and used a lot if
"sometype" is either a header in a buffer followed by arbitrary data, or
if the buffer consists of multiple packed blocks of type "sometype".
Takashi's suggestion adds the information that "sometype" is a header
followed by arbitrary data, so that's a good thing..
Yes, thanks for this variant.
Thomas
