1 /* $NetBSD: fvwrite.c,v 1.5 1996/03/29 23:29:09 jtc Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 #if 0 41 static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93"; 42 #endif 43 static char rcsid[] = "$NetBSD: fvwrite.c,v 1.5 1996/03/29 23:29:09 jtc Exp $"; 44 #endif /* LIBC_SCCS and not lint */ 45 46 #include <stdio.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 w = fp->_w; 116 if (fp->_flags & __SSTR) { 117 if (len < w) 118 w = len; 119 COPY(w); /* copy MIN(fp->_w,len), */ 120 fp->_w -= w; 121 fp->_p += w; 122 w = len; /* but pretend copied all */ 123 } else if (fp->_p > fp->_bf._base && len > w) { 124 /* fill and flush */ 125 COPY(w); 126 /* fp->_w -= w; */ /* unneeded */ 127 fp->_p += w; 128 if (fflush(fp)) 129 goto err; 130 } else if (len >= (w = fp->_bf._size)) { 131 /* write directly */ 132 w = (*fp->_write)(fp->_cookie, p, w); 133 if (w <= 0) 134 goto err; 135 } else { 136 /* fill and done */ 137 w = len; 138 COPY(w); 139 fp->_w -= w; 140 fp->_p += w; 141 } 142 p += w; 143 len -= w; 144 } while ((uio->uio_resid -= w) != 0); 145 } else { 146 /* 147 * Line buffered: like fully buffered, but we 148 * must check for newlines. Compute the distance 149 * to the first newline (including the newline), 150 * or `infinity' if there is none, then pretend 151 * that the amount to write is MIN(len,nldist). 152 */ 153 nlknown = 0; 154 nldist = 0; /* XXX just to keep gcc happy */ 155 do { 156 GETIOV(nlknown = 0); 157 if (!nlknown) { 158 nl = memchr((void *)p, '\n', len); 159 nldist = nl ? nl + 1 - p : len + 1; 160 nlknown = 1; 161 } 162 s = MIN(len, nldist); 163 w = fp->_w + fp->_bf._size; 164 if (fp->_p > fp->_bf._base && s > w) { 165 COPY(w); 166 /* fp->_w -= w; */ 167 fp->_p += w; 168 if (fflush(fp)) 169 goto err; 170 } else if (s >= (w = fp->_bf._size)) { 171 w = (*fp->_write)(fp->_cookie, p, w); 172 if (w <= 0) 173 goto err; 174 } else { 175 w = s; 176 COPY(w); 177 fp->_w -= w; 178 fp->_p += w; 179 } 180 if ((nldist -= w) == 0) { 181 /* copied the newline: flush and forget */ 182 if (fflush(fp)) 183 goto err; 184 nlknown = 0; 185 } 186 p += w; 187 len -= w; 188 } while ((uio->uio_resid -= w) != 0); 189 } 190 return (0); 191 192 err: 193 fp->_flags |= __SERR; 194 return (EOF); 195 } 196