On 16.08.2012 14:30, Corinna Vinschen wrote:
On Aug 16 14:11, Thomas Wolff wrote:
Hi Corinna,
On 16.08.2012 11:33, Corinna Vinschen wrote:
Hi Thomas,
thanks for the patch. I have a few minor nits:
On Aug 14 22:56, Thomas Wolff wrote:
...
+ char cprabuf [8 + 1]; /* need this length for surrogates */
+ if (len < 8)
+ {
+ _ptr = cprabuf;
+ _len = 8;
+ }
8? Why 8? The size appears to be rather artificial. The code should
use MB_CUR_MAX instead.
MB_CUR_MAX does not work because its value is 1 at this point
So what about MB_LEN_MAX then? There's no problem using a multiplier,
but a symbolic constant is always better than a numerical constant.
I've now used _MB_LEN_MAX from newlib.h, rather than MB_LEN_MAX from
limits.h (note the "_" distinction :) ),
because the latter, by its preceding comment, reserves the option to be
changed into a dynamic function in the future, which could then possibly
have the same problems as MB_CUR_MAX.
About the surrogates problem, I think I've found a solution:
I've added an explicit test to avoid processing of split surrogate pairs
(to that loop...); this seems to work now.
+ /* If using read-ahead buffer, copy to class read-ahead buffer
+ and deliver first byte. */
+ if (_ptr == cprabuf)
+ {
+ puts_readahead (cprabuf, ret);
+ * (char *) ptr = get_readahead ();
+ ret = 1;
(*) Ok, that works, but wouldn't it be more efficient to do that in
a tiny loop along the lines of
int x;
ret = 0;
while (ret < len && (x = get_readahead ()) >= 0)
ptr++ = x;
ret++;
?
I can add it if you prefer; I just didn't think it's worth the
effort and concerning efficiency, after that prior trial-and-error
count-down-loop...
Yeah, that's a valid point. But maybe we shouldn't make it slower
than necessary? If you have a good idea how to avoid the other
loop, don't hesitate to submit a patch.
Added the loop to use up the caller's buffer.
About avoiding the trial-and-error loop, I think that would require
digging into sys_mbstowcs (which doesn't even seem to behave as documented).
------
Thomas
--- sav/fhandler_clipboard.cc 2012-07-08 02:36:47.000000000 +0200
+++ ./fhandler_clipboard.cc 2012-08-16 16:08:23.782692300 +0200
@@ -222,6 +222,7 @@ fhandler_dev_clipboard::read (void *ptr,
UINT formatlist[2];
int format;
LPVOID cb_data;
+ int rach;
if (!OpenClipboard (NULL))
{
@@ -243,12 +244,24 @@ fhandler_dev_clipboard::read (void *ptr,
cygcb_t *clipbuf = (cygcb_t *) cb_data;
if (pos < clipbuf->len)
- {
+ {
ret = ((len > (clipbuf->len - pos)) ? (clipbuf->len - pos) : len);
memcpy (ptr, clipbuf->data + pos , ret);
pos += ret;
}
}
+ else if ((rach = get_readahead ()) >= 0)
+ {
+ /* Deliver from read-ahead buffer. */
+ char * out_ptr = (char *) ptr;
+ * out_ptr++ = rach;
+ ret = 1;
+ while (ret < len && (rach = get_readahead ()) >= 0)
+ {
+ * out_ptr++ = rach;
+ ret++;
+ }
+ }
else
{
wchar_t *buf = (wchar_t *) cb_data;
@@ -256,25 +269,54 @@ fhandler_dev_clipboard::read (void *ptr,
size_t glen = GlobalSize (hglb) / sizeof (WCHAR) - 1;
if (pos < glen)
{
+ /* If caller's buffer is too small to hold at least one
+ max-size character, redirect algorithm to local
+ read-ahead buffer, finally fill class read-ahead buffer
+ with result and feed caller from there. */
+ char * conv_ptr = (char *) ptr;
+ size_t conv_len = len;
+#define cprabuf_len _MB_LEN_MAX /* newlib's max MB_CUR_MAX of all
encodings */
+ char cprabuf [cprabuf_len];
+ if (len < cprabuf_len)
+ {
+ conv_ptr = cprabuf;
+ conv_len = cprabuf_len;
+ }
+
/* Comparing apples and oranges here, but the below loop could become
extremly slow otherwise. We rather return a few bytes less than
possible instead of being even more slow than usual... */
- if (glen > pos + len)
- glen = pos + len;
+ if (glen > pos + conv_len)
+ glen = pos + conv_len;
/* This loop is necessary because the number of bytes returned by
sys_wcstombs does not indicate the number of wide chars used for
it, so we could potentially drop wide chars. */
while ((ret = sys_wcstombs (NULL, 0, buf + pos, glen - pos))
!= (size_t) -1
- && ret > len)
+ && (ret > conv_len
+ /* Skip separated high surrogate: */
+ || ((buf [pos + glen - 1] & 0xFC00) == 0xD800 && glen -
pos > 1)))
--glen;
if (ret == (size_t) -1)
ret = 0;
else
{
- ret = sys_wcstombs ((char *) ptr, (size_t) -1,
+ ret = sys_wcstombs ((char *) conv_ptr, (size_t) -1,
buf + pos, glen - pos);
pos = glen;
+ /* If using read-ahead buffer, copy to class read-ahead buffer
+ and deliver first byte. */
+ if (conv_ptr == cprabuf)
+ {
+ puts_readahead (cprabuf, ret);
+ char * out_ptr = (char *) ptr;
+ ret = 0;
+ while (ret < len && (rach = get_readahead ()) >= 0)
+ {
+ * out_ptr++ = rach;
+ ret++;
+ }
+ }
}
}
}
