fvwrite.c revision 50476
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 "$FreeBSD: head/lib/libc/stdio/fvwrite.c 50476 1999-08-28 00:22:10Z peter $"; 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 */ 57int 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 210err: 211 fp->_flags |= __SERR; 212 return (EOF); 213} 214