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/* Copyright (C) 2004 Manuel Novoa III <mjn3@codepoet.org>
*
* GNU Library General Public License (LGPL) version 2 or later.
*
* Dedicated to Toni. See uClibc/DEDICATION.mjn3 for details.
*/
#include "_stdio.h"
/* Given a writing stream with no buffered output, write the
* data in 'buf' (which may be the stream's bufstart) of size
* 'bufsize' to the stream. If a write error occurs, set the
* stream's error indicator and (if buffering) buffer as much
* data as possible (FBF) or only up to '\n' (LBF) to implement
* "as if fputc()" clause in the standard.
*
* Returns the number of bytes written and/or buffered.
*
* Notes:
* Calling with bufsize == 0 is permitted, and buf is ignored in
* that case.
* We implement fflush() by setting bufpos to bufstart and passing
* bufstart as the buf arg. If there is a write error, the
* unwritten buffered data will simply be moved to the beginning
* of the buffer. Since the data obviously fits in the buffer
* and since there will be no '\n' chars in the buffer in the LBF
* case, no data will be lost.
* NOT THREADSAFE! Assumes stream already locked if necessary.
*/
size_t attribute_hidden __stdio_WRITE(register FILE *stream,
register const unsigned char *buf, size_t bufsize)
{
size_t todo;
ssize_t rv, stodo;
__STDIO_STREAM_VALIDATE(stream);
assert(stream->__filedes >= -1);
assert(__STDIO_STREAM_IS_WRITING(stream));
assert(!__STDIO_STREAM_BUFFER_WUSED(stream)); /* Buffer must be empty. */
todo = bufsize;
while (todo != 0) {
stodo = (todo <= SSIZE_MAX) ? todo : SSIZE_MAX;
rv = __WRITE(stream, (char *) buf, stodo);
if (rv >= 0) {
#ifdef __UCLIBC_MJN3_ONLY__
#warning TODO: Make custom stream write return check optional.
#endif
#ifdef __UCLIBC_HAS_GLIBC_CUSTOM_STREAMS__
assert(rv <= stodo);
if (rv > stodo) { /* Wrote more than stodo! */
/* abort(); */
}
#endif
todo -= rv;
buf += rv;
} else {
__STDIO_STREAM_SET_ERROR(stream);
/* We buffer data on "transient" errors, but discard it
* on "hard" ones. Example of a hard error:
*
* close(fileno(stdout));
* printf("Hi there 1\n"); // EBADF
* dup2(good_fd, fileno(stdout));
* printf("Hi there 2\n"); // buffers new data
*
* This program should not print "Hi there 1" to good_fd.
* The rationale is that the caller of writing operation
* should check for error and act on it.
* If he didn't, then future users of the stream
* have no idea what to do.
* It's least confusing to at least not burden them with
* some hidden buffered crap in the buffer.
*/
if (errno != EINTR && errno != EAGAIN) {
/* do we have other "soft" errors? */
break;
}
#ifdef __STDIO_BUFFERS
stodo = __STDIO_STREAM_BUFFER_SIZE(stream);
if (stodo != 0) {
unsigned char *s;
if (stodo > todo) {
stodo = todo;
}
s = stream->__bufstart;
do {
*s = *buf;
if ((*s == '\n')
&& __STDIO_STREAM_IS_LBF(stream)
) {
break;
}
++s;
++buf;
} while (--stodo);
stream->__bufpos = s;
todo -= (s - stream->__bufstart);
}
#endif /* __STDIO_BUFFERS */
bufsize -= todo;
break;
}
}
__STDIO_STREAM_VALIDATE(stream);
return bufsize;
}
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