stdio.subproj/fvwrite.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software contributed to Berkeley by
  27  * Chris Torek.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <stdio.h>
  60 #include <string.h>
  61 #include "local.h"
  62 #include "fvwrite.h"
  63
  64 /*
  65  * Write some memory regions.  Return zero on success, EOF on error.
  66  *
  67  * This routine is large and unsightly, but most of the ugliness due
  68  * to the three different kinds of output buffering is handled here.
  69  */
  70 int
  71 __sfvwrite(fp, uio)
  72         register FILE *fp;
  73         register struct __suio *uio;
  74 {
  75         register size_t len;
  76         register char *p;
  77         register struct __siov *iov;
  78         register int w, s;
  79         char *nl;
  80         int nlknown, nldist;
  81
  82         if ((len = uio->uio_resid) == 0)
  83                 return (0);
  84         /* make sure we can write */
  85         if (cantwrite(fp))
  86                 return (EOF);
  87
  88 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  89 #define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
  90
  91         iov = uio->uio_iov;
  92         p = iov->iov_base;
  93         len = iov->iov_len;
  94         iov++;
  95 #define GETIOV(extra_work) \
  96         while (len == 0) { \
  97                 extra_work; \
  98                 p = iov->iov_base; \
  99                 len = iov->iov_len; \
 100                 iov++; \
 101         }
 102         if (fp->_flags & __SNBF) {
 103                 /*
 104                  * Unbuffered: write up to BUFSIZ bytes at a time.
 105                  */
 106                 do {
 107                         GETIOV(;);
 108                         w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
 109                         if (w <= 0)
 110                                 goto err;
 111                         p += w;
 112                         len -= w;
 113                 } while ((uio->uio_resid -= w) != 0);
 114         } else if ((fp->_flags & __SLBF) == 0) {
 115                 /*
 116                  * Fully buffered: fill partially full buffer, if any,
 117                  * and then flush.  If there is no partial buffer, write
 118                  * one _bf._size byte chunk directly (without copying).
 119                  *
 120                  * String output is a special case: write as many bytes
 121                  * as fit, but pretend we wrote everything.  This makes
 122                  * snprintf() return the number of bytes needed, rather
 123                  * than the number used, and avoids its write function
 124                  * (so that the write function can be invalid).
 125                  */
 126                 do {
 127                         GETIOV(;);
 128                         w = fp->_w;
 129                         if (fp->_flags & __SSTR) {
 130                                 if (len < w)
 131                                         w = len;
 132                                 COPY(w);        /* copy MIN(fp->_w,len), */
 133                                 fp->_w -= w;
 134                                 fp->_p += w;
 135                                 w = len;        /* but pretend copied all */
 136                         } else if (fp->_p > fp->_bf._base && len > w) {
 137                                 /* fill and flush */
 138                                 COPY(w);
 139                                 /* fp->_w -= w; */ /* unneeded */
 140                                 fp->_p += w;
 141                                 if (fflush(fp))
 142                                         goto err;
 143                         } else if (len >= (w = fp->_bf._size)) {
 144                                 /* write directly */
 145                                 w = (*fp->_write)(fp->_cookie, p, w);
 146                                 if (w <= 0)
 147                                         goto err;
 148                         } else {
 149                                 /* fill and done */
 150                                 w = len;
 151                                 COPY(w);
 152                                 fp->_w -= w;
 153                                 fp->_p += w;
 154                         }
 155                         p += w;
 156                         len -= w;
 157                 } while ((uio->uio_resid -= w) != 0);
 158         } else {
 159                 /*
 160                  * Line buffered: like fully buffered, but we
 161                  * must check for newlines.  Compute the distance
 162                  * to the first newline (including the newline),
 163                  * or `infinity' if there is none, then pretend
 164                  * that the amount to write is MIN(len,nldist).
 165                  */
 166                 nlknown = 0;
 167                 nldist = 0;     /* XXX just to keep gcc happy */
 168                 do {
 169                         GETIOV(nlknown = 0);
 170                         if (!nlknown) {
 171                                 nl = memchr((void *)p, '\n', len);
 172                                 nldist = nl ? nl + 1 - p : len + 1;
 173                                 nlknown = 1;
 174                         }
 175                         s = MIN(len, nldist);
 176                         w = fp->_w + fp->_bf._size;
 177                         if (fp->_p > fp->_bf._base && s > w) {
 178                                 COPY(w);
 179                                 /* fp->_w -= w; */
 180                                 fp->_p += w;
 181                                 if (fflush(fp))
 182                                         goto err;
 183                         } else if (s >= (w = fp->_bf._size)) {
 184                                 w = (*fp->_write)(fp->_cookie, p, w);
 185                                 if (w <= 0)
 186                                         goto err;
 187                         } else {
 188                                 w = s;
 189                                 COPY(w);
 190                                 fp->_w -= w;
 191                                 fp->_p += w;
 192                         }
 193                         if ((nldist -= w) == 0) {
 194                                 /* copied the newline: flush and forget */
 195                                 if (fflush(fp))
 196                                         goto err;
 197                                 nlknown = 0;
 198                         }
 199                         p += w;
 200                         len -= w;
 201                 } while ((uio->uio_resid -= w) != 0);
 202         }
 203         return (0);
 204
 205 err:
 206         fp->_flags |= __SERR;
 207         return (EOF);
 208 }