stdio/fvwrite.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 #if 0
  39 static char sccsid[] = "@(#)fvwrite.c   8.1 (Berkeley) 6/4/93";
  40 #endif
  41 static const char rcsid[] =
  42   "$FreeBSD: src/lib/libc/stdio/fvwrite.c,v 1.10 1999/08/28 00:01:06 peter Exp $";
  43 #endif /* LIBC_SCCS and not lint */
  44
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include "local.h"
  49 #include "fvwrite.h"
  50
  51 /*
  52  * Write some memory regions.  Return zero on success, EOF on error.
  53  *
  54  * This routine is large and unsightly, but most of the ugliness due
  55  * to the three different kinds of output buffering is handled here.
  56  */
  57 int
  58 __sfvwrite(fp, uio)
  59         register FILE *fp;
  60         register struct __suio *uio;
  61 {
  62         register size_t len;
  63         register char *p;
  64         register struct __siov *iov;
  65         register int w, s;
  66         char *nl;
  67         int nlknown, nldist;
  68
  69         if ((len = uio->uio_resid) == 0)
  70                 return (0);
  71         /* make sure we can write */
  72         if (cantwrite(fp))
  73                 return (EOF);
  74
  75 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  76 #define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
  77
  78         iov = uio->uio_iov;
  79         p = iov->iov_base;
  80         len = iov->iov_len;
  81         iov++;
  82 #define GETIOV(extra_work) \
  83         while (len == 0) { \
  84                 extra_work; \
  85                 p = iov->iov_base; \
  86                 len = iov->iov_len; \
  87                 iov++; \
  88         }
  89         if (fp->_flags & __SNBF) {
  90                 /*
  91                  * Unbuffered: write up to BUFSIZ bytes at a time.
  92                  */
  93                 do {
  94                         GETIOV(;);
  95                         w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
  96                         if (w <= 0)
  97                                 goto err;
  98                         p += w;
  99                         len -= w;
 100                 } while ((uio->uio_resid -= w) != 0);
 101         } else if ((fp->_flags & __SLBF) == 0) {
 102                 /*
 103                  * Fully buffered: fill partially full buffer, if any,
 104                  * and then flush.  If there is no partial buffer, write
 105                  * one _bf._size byte chunk directly (without copying).
 106                  *
 107                  * String output is a special case: write as many bytes
 108                  * as fit, but pretend we wrote everything.  This makes
 109                  * snprintf() return the number of bytes needed, rather
 110                  * than the number used, and avoids its write function
 111                  * (so that the write function can be invalid).
 112                  */
 113                 do {
 114                         GETIOV(;);
 115                         if ((fp->_flags & (__SALC | __SSTR)) ==
 116                             (__SALC | __SSTR) && fp->_w < len) {
 117                                 size_t blen = fp->_p - fp->_bf._base;
 118
 119                                 /*
 120                                  * Alloc an extra 128 bytes (+ 1 for NULL)
 121                                  * so we don't call realloc(3) so often.
 122                                  */
 123                                 fp->_w = len + 128;
 124                                 fp->_bf._size = blen + len + 128;
 125                                 fp->_bf._base =
 126                                     reallocf(fp->_bf._base, fp->_bf._size + 1);
 127                                 if (fp->_bf._base == NULL)
 128                                         goto err;
 129                                 fp->_p = fp->_bf._base + blen;
 130                         }
 131                         w = fp->_w;
 132                         if (fp->_flags & __SSTR) {
 133                                 if (len < w)
 134                                         w = len;
 135                                 if (w > 0) {
 136                                         COPY(w);        /* copy MIN(fp->_w,len), */
 137                                         fp->_w -= w;
 138                                         fp->_p += w;
 139                                 }
 140                                 w = len;        /* but pretend copied all */
 141                         } else if (fp->_p > fp->_bf._base && len > w) {
 142                                 /* fill and flush */
 143                                 COPY(w);
 144                                 /* fp->_w -= w; */ /* unneeded */
 145                                 fp->_p += w;
 146                                 if (fflush(fp))
 147                                         goto err;
 148                         } else if (len >= (w = fp->_bf._size)) {
 149                                 /* write directly */
 150                                 w = (*fp->_write)(fp->_cookie, p, w);
 151                                 if (w <= 0)
 152                                         goto err;
 153                         } else {
 154                                 /* fill and done */
 155                                 w = len;
 156                                 COPY(w);
 157                                 fp->_w -= w;
 158                                 fp->_p += w;
 159                         }
 160                         p += w;
 161                         len -= w;
 162                 } while ((uio->uio_resid -= w) != 0);
 163         } else {
 164                 /*
 165                  * Line buffered: like fully buffered, but we
 166                  * must check for newlines.  Compute the distance
 167                  * to the first newline (including the newline),
 168                  * or `infinity' if there is none, then pretend
 169                  * that the amount to write is MIN(len,nldist).
 170                  */
 171                 nlknown = 0;
 172                 nldist = 0;     /* XXX just to keep gcc happy */
 173                 do {
 174                         GETIOV(nlknown = 0);
 175                         if (!nlknown) {
 176                                 nl = memchr((void *)p, '\n', len);
 177                                 nldist = nl ? nl + 1 - p : len + 1;
 178                                 nlknown = 1;
 179                         }
 180                         s = MIN(len, nldist);
 181                         w = fp->_w + fp->_bf._size;
 182                         if (fp->_p > fp->_bf._base && s > w) {
 183                                 COPY(w);
 184                                 /* fp->_w -= w; */
 185                                 fp->_p += w;
 186                                 if (fflush(fp))
 187                                         goto err;
 188                         } else if (s >= (w = fp->_bf._size)) {
 189                                 w = (*fp->_write)(fp->_cookie, p, w);
 190                                 if (w <= 0)
 191                                         goto err;
 192                         } else {
 193                                 w = s;
 194                                 COPY(w);
 195                                 fp->_w -= w;
 196                                 fp->_p += w;
 197                         }
 198                         if ((nldist -= w) == 0) {
 199                                 /* copied the newline: flush and forget */
 200                                 if (fflush(fp))
 201                                         goto err;
 202                                 nlknown = 0;
 203                         }
 204                         p += w;
 205                         len -= w;
 206                 } while ((uio->uio_resid -= w) != 0);
 207         }
 208         return (0);
 209
 210 err:
 211         fp->_flags |= __SERR;
 212         return (EOF);
 213 }