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;