ack/lang/cem/libcc.ansi/stdio/fillbuf.c

/*
 * fillbuf.c - fill a buffer
 */
/* $Id$ */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include "loc_incl.h"

int __fillbuf(register FILE* stream)
{
	static unsigned char ch[FOPEN_MAX];
	register int i;

	stream->_count = 0;
	if (fileno(stream) < 0)
		return EOF;
	if (io_testflag(stream, _IOEOF))
		return EOF;
	if (!io_testflag(stream, _IOREAD))
	{
		stream->_flags |= _IOERR;
		return EOF;
	}
	if (io_testflag(stream, _IOWRITING))
	{
		stream->_flags |= _IOERR;
		return EOF;
	}

	if (!io_testflag(stream, _IOREADING))
		stream->_flags |= _IOREADING;

	if (!io_testflag(stream, _IONBF) && !stream->_buf)
	{
		stream->_buf = (unsigned char*)malloc(BUFSIZ);
		if (!stream->_buf)
		{
			stream->_flags |= _IONBF;
		}
		else
		{
			stream->_flags |= _IOMYBUF;
			stream->_bufsiz = BUFSIZ;
		}
	}

	/* flush line-buffered output when filling an input buffer */
	for (i = 0; i < FOPEN_MAX; i++)
	{
		if (__iotab[i] && io_testflag(__iotab[i], _IOLBF))
			if (io_testflag(__iotab[i], _IOWRITING))
				(void)fflush(__iotab[i]);
	}

	if (!stream->_buf)
	{
		stream->_buf = &ch[fileno(stream)];
		stream->_bufsiz = 1;
	}
	stream->_ptr = stream->_buf;
	stream->_count = read(stream->_fd, (char*)stream->_buf, stream->_bufsiz);

	if (stream->_count <= 0)
	{
		if (stream->_count == 0)
		{
			stream->_flags |= _IOEOF;
		}
		else
			stream->_flags |= _IOERR;

		return EOF;
	}
	stream->_count--;

	return *stream->_ptr++;
}