fvwrite.c revision 31981
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 39static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93"; 40#endif 41static const char rcsid[] = 42 "$Id: fvwrite.c,v 1.6 1997/12/24 13:17:13 ache Exp $"; 43#endif /* LIBC_SCCS and not lint */ 44 45#include <stdio.h> 46#include <string.h> 47#include "local.h" 48#include "fvwrite.h" 49 50/* 51 * Write some memory regions. Return zero on success, EOF on error. 52 * 53 * This routine is large and unsightly, but most of the ugliness due 54 * to the three different kinds of output buffering is handled here. 55 */ 56int 57__sfvwrite(fp, uio) 58 register FILE *fp; 59 register struct __suio *uio; 60{ 61 register size_t len; 62 register char *p; 63 register struct __siov *iov; 64 register int w, s; 65 char *nl; 66 int nlknown, nldist; 67 68 if ((len = uio->uio_resid) == 0) 69 return (0); 70 /* make sure we can write */ 71 if (cantwrite(fp)) 72 return (EOF); 73 74#define MIN(a, b) ((a) < (b) ? (a) : (b)) 75#define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n)) 76 77 iov = uio->uio_iov; 78 p = iov->iov_base; 79 len = iov->iov_len; 80 iov++; 81#define GETIOV(extra_work) \ 82 while (len == 0) { \ 83 extra_work; \ 84 p = iov->iov_base; \ 85 len = iov->iov_len; \ 86 iov++; \ 87 } 88 if (fp->_flags & __SNBF) { 89 /* 90 * Unbuffered: write up to BUFSIZ bytes at a time. 91 */ 92 do { 93 GETIOV(;); 94 w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ)); 95 if (w <= 0) 96 goto err; 97 p += w; 98 len -= w; 99 } while ((uio->uio_resid -= w) != 0); 100 } else if ((fp->_flags & __SLBF) == 0) { 101 /* 102 * Fully buffered: fill partially full buffer, if any, 103 * and then flush. If there is no partial buffer, write 104 * one _bf._size byte chunk directly (without copying). 105 * 106 * String output is a special case: write as many bytes 107 * as fit, but pretend we wrote everything. This makes 108 * snprintf() return the number of bytes needed, rather 109 * than the number used, and avoids its write function 110 * (so that the write function can be invalid). 111 */ 112 do { 113 GETIOV(;); 114 w = fp->_w; 115 if (fp->_flags & __SSTR) { 116 if (len < w) 117 w = len; 118 if (w > 0) { 119 COPY(w); /* copy MIN(fp->_w,len), */ 120 fp->_w -= w; 121 fp->_p += w; 122 } 123 w = len; /* but pretend copied all */ 124 } else if (fp->_p > fp->_bf._base && len > w) { 125 /* fill and flush */ 126 COPY(w); 127 /* fp->_w -= w; */ /* unneeded */ 128 fp->_p += w; 129 if (fflush(fp)) 130 goto err; 131 } else if (len >= (w = fp->_bf._size)) { 132 /* write directly */ 133 w = (*fp->_write)(fp->_cookie, p, w); 134 if (w <= 0) 135 goto err; 136 } else { 137 /* fill and done */ 138 w = len; 139 COPY(w); 140 fp->_w -= w; 141 fp->_p += w; 142 } 143 p += w; 144 len -= w; 145 } while ((uio->uio_resid -= w) != 0); 146 } else { 147 /* 148 * Line buffered: like fully buffered, but we 149 * must check for newlines. Compute the distance 150 * to the first newline (including the newline), 151 * or `infinity' if there is none, then pretend 152 * that the amount to write is MIN(len,nldist). 153 */ 154 nlknown = 0; 155 nldist = 0; /* XXX just to keep gcc happy */ 156 do { 157 GETIOV(nlknown = 0); 158 if (!nlknown) { 159 nl = memchr((void *)p, '\n', len); 160 nldist = nl ? nl + 1 - p : len + 1; 161 nlknown = 1; 162 } 163 s = MIN(len, nldist); 164 w = fp->_w + fp->_bf._size; 165 if (fp->_p > fp->_bf._base && s > w) { 166 COPY(w); 167 /* fp->_w -= w; */ 168 fp->_p += w; 169 if (fflush(fp)) 170 goto err; 171 } else if (s >= (w = fp->_bf._size)) { 172 w = (*fp->_write)(fp->_cookie, p, w); 173 if (w <= 0) 174 goto err; 175 } else { 176 w = s; 177 COPY(w); 178 fp->_w -= w; 179 fp->_p += w; 180 } 181 if ((nldist -= w) == 0) { 182 /* copied the newline: flush and forget */ 183 if (fflush(fp)) 184 goto err; 185 nlknown = 0; 186 } 187 p += w; 188 len -= w; 189 } while ((uio->uio_resid -= w) != 0); 190 } 191 return (0); 192 193err: 194 fp->_flags |= __SERR; 195 return (EOF); 196} 197