gonzui

    1: /*      $OpenBSD: fwrite.c,v 1.10 2009/11/21 09:53:44 guenther Exp $ */
    2: /*-
    3:  * Copyright (c) 1990, 1993
    4:  *      The Regents of the University of California.  All rights reserved.
    5:  *
    6:  * This code is derived from software contributed to Berkeley by
    7:  * Chris Torek.
    8:  *
    9:  * Redistribution and use in source and binary forms, with or without
   10:  * modification, are permitted provided that the following conditions
   11:  * are met:
   12:  * 1. Redistributions of source code must retain the above copyright
   13:  *    notice, this list of conditions and the following disclaimer.
   14:  * 2. Redistributions in binary form must reproduce the above copyright
   15:  *    notice, this list of conditions and the following disclaimer in the
   16:  *    documentation and/or other materials provided with the distribution.
   17:  * 3. Neither the name of the University nor the names of its contributors
   18:  *    may be used to endorse or promote products derived from this software
   19:  *    without specific prior written permission.
   20:  *
   21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31:  * SUCH DAMAGE.
   32:  */
   33: 
   34: #include <stdio.h>
   35: #include "local.h"
   36: #include "fvwrite.h"
   37: 
   38: /*
   39:  * Write `count' objects (each size `size') from memory to the given file.
   40:  * Return the number of whole objects written.
   41:  */
   42: size_t
   43: fwrite(const void *buf, size_t size, size_t count, FILE *fp)
   44: {
   45:         size_t n;
   46:         struct __suio uio;
   47:         struct __siov iov;
   48:         int ret;
   49: 
   50:         /*
   51:          * ANSI and SUSv2 require a return value of 0 if size or count are 0.
   52:          */
   53:         if ((n = count * size) == 0)
   54:                 return (0);
   55: 
   56:         iov.iov_base = (void *)buf;
   57:         uio.uio_resid = iov.iov_len = n;
   58:         uio.uio_iov = &iov;
   59:         uio.uio_iovcnt = 1;
   60: 
   61:         /*
   62:          * The usual case is success (__sfvwrite returns 0);
   63:          * skip the divide if this happens, since divides are
   64:          * generally slow and since this occurs whenever size==0.
   65:          */
   66:         FLOCKFILE(fp);
   67:         _SET_ORIENTATION(fp, -1);
   68:         ret = __sfvwrite(fp, &uio);
   69:         FUNLOCKFILE(fp);
   70:         if (ret == 0)
   71:                 return (count);
   72:         return ((n - uio.uio_resid) / size);
   73: }