Module Name: src
Committed By: christos
Date: Fri Mar 29 22:39:41 UTC 2024
Modified Files:
src/lib/libc/stdio: fvwrite.c
Log Message:
>From enh at google dot com in tech-userlevel. Don't limit writes to BUFSIZ,
change the limit to INT_MAX; improves performance dramatically. From:
https://github.com/apple-oss-distributions/Libc/commit/\
c5a3293354e22262702a3add5b2dfc9bb0b93b85\
#diff-3b844a19cfb0aab1a23f7fbc457d3bce7453513730c489a72f66ff89d6557ff3
To generate a diff of this commit:
cvs rdiff -u -r1.30 -r1.31 src/lib/libc/stdio/fvwrite.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/stdio/fvwrite.c
diff -u src/lib/libc/stdio/fvwrite.c:1.30 src/lib/libc/stdio/fvwrite.c:1.31
--- src/lib/libc/stdio/fvwrite.c:1.30 Thu Jul 22 13:08:15 2021
+++ src/lib/libc/stdio/fvwrite.c Fri Mar 29 18:39:41 2024
@@ -1,4 +1,4 @@
-/* $NetBSD: fvwrite.c,v 1.30 2021/07/22 17:08:15 christos Exp $ */
+/* $NetBSD: fvwrite.c,v 1.31 2024/03/29 22:39:41 christos Exp $ */
/*-
* Copyright (c) 1990, 1993
@@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93";
#else
-__RCSID("$NetBSD: fvwrite.c,v 1.30 2021/07/22 17:08:15 christos Exp $");
+__RCSID("$NetBSD: fvwrite.c,v 1.31 2024/03/29 22:39:41 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@@ -99,11 +99,12 @@ __sfvwrite(FILE *fp, struct __suio *uio)
}
if (fp->_flags & __SNBF) {
/*
- * Unbuffered: write up to BUFSIZ bytes at a time.
+ * Unbuffered: write up to INT_MAX bytes at a time, to not
+ * truncate the value of len if it is greater than 2^31 bytes.
*/
do {
GETIOV(;);
- w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
+ w = (*fp->_write)(fp->_cookie, p, MIN(len, INT_MAX));
if (w <= 0)
goto err;
p += w;
@@ -113,7 +114,8 @@ __sfvwrite(FILE *fp, struct __suio *uio)
/*
* Fully buffered: fill partially full buffer, if any,
* and then flush. If there is no partial buffer, write
- * one _bf._size byte chunk directly (without copying).
+ * entire payload directly (without copying) up to a multiple
+ * of the buffer size.
*
* String output is a special case: write as many bytes
* as fit, but pretend we wrote everything. This makes
@@ -159,7 +161,15 @@ __sfvwrite(FILE *fp, struct __suio *uio)
if (fflush(fp))
goto err;
} else if (len >= (size_t)(w = fp->_bf._size)) {
- /* write directly */
+ /*
+ * write directly up to INT_MAX or greatest
+ * multiple of buffer size (whatever is
+ * smaller), keeping in the memory buffer the
+ * remaining part of payload that is smaller
+ * than buffer size.
+ */
+ if (w != 0)
+ w = MIN(w * (len / w), INT_MAX);
w = (*fp->_write)(fp->_cookie, p, (size_t)w);
if (w <= 0)
goto err;
