usr/src/lib/libbc/libc/stdio/common/fwrite.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"  /* from S5R2 3.6 */
  31
  32 /*LINTLIBRARY*/
  33 /*
  34  * This version writes directly to the buffer rather than looping on putc.
  35  * Ptr args aren't checked for NULL because the program would be a
  36  * catastrophic mess anyway.  Better to abort than just to return NULL.
  37  *
  38  * This version does buffered writes larger than BUFSIZ directly, when
  39  * the buffer is empty.
  40  */
  41 #include <stdio.h>
  42 #include "stdiom.h"
  43
  44 #define MIN(x, y)       (x < y ? x : y)
  45
  46 extern char *memcpy();
  47
  48 int
  49 fwrite(ptr, size, count, iop)
  50 char *ptr;
  51 int size, count;
  52 register FILE *iop;
  53 {
  54         register unsigned nleft;
  55         register int n;
  56         register unsigned char *cptr, *bufend;
  57         register unsigned char *prev_ptr;
  58
  59         if (size <= 0 || count <= 0 || _WRTCHK(iop))
  60                 return (0);
  61
  62         bufend = iop->_base + iop->_bufsiz;
  63         nleft = count*size;
  64
  65         /* if the file is unbuffered, or if the iop->ptr = iop->base, and there
  66            is > BUFSZ chars to write, we can do a direct write */
  67         prev_ptr = iop->_ptr;
  68         if (iop->_base >= iop->_ptr)  { /*this covers the unbuffered case, too*/
  69                 if (((iop->_flag & _IONBF) != 0) || (nleft >= BUFSIZ))  {
  70                         if ((n=write(fileno(iop),ptr,nleft)) != nleft)
  71                             {
  72                                 iop->_flag |= _IOERR;
  73                                 n = (n >= 0) ? n : 0;
  74                         }
  75                         return n/size;
  76                 }
  77         }
  78         /* Put characters in the buffer */
  79         /* note that the meaning of n when just starting this loop is
  80            irrelevant.  It is defined in the loop */
  81         for (; ; ptr += n) {
  82                 while ((n = bufend - (cptr = iop->_ptr)) <= 0)  /* full buf */
  83                         if (_xflsbuf(iop) == EOF)
  84                                 return (count - (nleft + size - 1)/size);
  85                 n = MIN(nleft, n);
  86                 (void) memcpy((char *) cptr, ptr, n);
  87                 iop->_cnt -= n;
  88                 iop->_ptr += n;
  89                 _BUFSYNC(iop);
  90                 /* done; flush if linebuffered with a newline */
  91                 if ((nleft -= n) == 0)  {
  92                         if (iop->_flag & (_IOLBF | _IONBF)) {
  93                                 if ((iop->_flag & _IONBF) || (memchr(prev_ptr,
  94                                         '\n',iop->_ptr - prev_ptr) != NULL))  {
  95                                         (void) _xflsbuf(iop);
  96                                 }
  97                         }
  98                         return (count);
  99                 }
 100         }
 101 }