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32 * @(#)fvwrite.c 8.1 (Berkeley) 6/4/93
33 * $FreeBSD: head/lib/libc/stdio/fvwrite.c 249810 2013-04-23 14:36:44Z emaste $
42 * Write some memory regions. Return zero on success, EOF on error.
44 * This routine is large and unsightly, but most of the ugliness due
45 * to the three different kinds of output buffering is handled here.
48 __sfvwrite(FILE *fp, struct __suio *uio)
57 if (uio->uio_resid == 0)
59 /* make sure we can write */
60 if (prepwrite(fp) != 0)
63 #define MIN(a, b) ((a) < (b) ? (a) : (b))
64 #define COPY(n) (void)memcpy((void *)fp->pub._p, (void *)p, (size_t)(n))
70 #define GETIOV(extra_work) \
77 if (fp->pub._flags & __SNBF) {
79 * Unbuffered: write up to BUFSIZ bytes at a time.
83 w = _swrite(fp, p, MIN(len, BUFSIZ));
88 } while ((uio->uio_resid -= w) != 0);
89 } else if ((fp->pub._flags & __SLBF) == 0) {
91 * Fully buffered: fill partially full buffer, if any,
92 * and then flush. If there is no partial buffer, write
93 * one _bf._size byte chunk directly (without copying).
95 * String output is a special case: write as many bytes
96 * as fit, but pretend we wrote everything. This makes
97 * snprintf() return the number of bytes needed, rather
98 * than the number used, and avoids its write function
99 * (so that the write function can be invalid).
103 if ((fp->pub._flags & (__SALC | __SSTR)) ==
104 (__SALC | __SSTR) && fp->pub._w < len) {
105 size_t blen = fp->pub._p - fp->_bf._base;
108 * Alloc an extra 128 bytes (+ 1 for NULL)
109 * so we don't call realloc(3) so often.
111 fp->pub._w = len + 128;
112 fp->_bf._size = blen + len + 128;
114 reallocf(fp->_bf._base, fp->_bf._size + 1);
115 if (fp->_bf._base == NULL)
117 fp->pub._p = fp->_bf._base + blen;
120 if (fp->pub._flags & __SSTR) {
124 COPY(w); /* copy MIN(fp->pub._w,len), */
128 w = len; /* but pretend copied all */
129 } else if (fp->pub._p > fp->_bf._base && len > w) {
132 /* fp->pub._w -= w; */ /* unneeded */
136 } else if (len >= (w = fp->_bf._size)) {
138 w = _swrite(fp, p, w);
150 } while ((uio->uio_resid -= w) != 0);
153 * Line buffered: like fully buffered, but we
154 * must check for newlines. Compute the distance
155 * to the first newline (including the newline),
156 * or `infinity' if there is none, then pretend
157 * that the amount to write is MIN(len,nldist).
160 nldist = 0; /* XXX just to keep gcc happy */
164 nl = memchr((void *)p, '\n', len);
165 nldist = nl ? nl + 1 - p : len + 1;
168 s = MIN(len, nldist);
169 w = fp->pub._w + fp->_bf._size;
170 if (fp->pub._p > fp->_bf._base && s > w) {
172 /* fp->pub._w -= w; */
176 } else if (s >= (w = fp->_bf._size)) {
177 w = _swrite(fp, p, w);
186 if ((nldist -= w) == 0) {
187 /* copied the newline: flush and forget */
194 } while ((uio->uio_resid -= w) != 0);
199 fp->pub._flags |= __SERR;