On Mon, Dec 01, 2014 at 16:22, Elliott Hughes wrote:
>
> this code takes minutes to run on a high-end desktop when using the
> OpenBSD fread:
Yikes. Thanks for the patch. Here's a version for OpenBSD.
Index: stdio/fread.c
===================================================================
RCS file: /cvs/src/lib/libc/stdio/fread.c,v
retrieving revision 1.12
diff -u -p -r1.12 fread.c
--- stdio/fread.c 1 May 2014 16:40:36 -0000 1.12
+++ stdio/fread.c 2 Dec 2014 08:02:37 -0000
@@ -68,6 +68,21 @@ fread(void *buf, size_t size, size_t cou
fp->_r = 0;
total = resid;
p = buf;
+
+ if ((fp->_flags & __SNBF) != 0) {
+ /*
+ * We know if we're unbuffered that our buffer is empty, so
+ * we can just read directly. This is much faster than the
+ * loop below which will perform a series of one byte reads.
+ */
+ while (resid > 0 && (r = (*fp->_read)(fp->_cookie, p, resid)) >
0) {
+ p += r;
+ resid -= r;
+ }
+ FUNLOCKFILE(fp);
+ return ((total - resid) / size);
+ }
+
while (resid > (r = fp->_r)) {
(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
fp->_p += r;
