source: trunk/minix/lib/stdio/fillbuf.c@ 20

/*
 * fillbuf.c - fill a buffer
 */
/* $Header: /cvsup/minix/src/lib/stdio/fillbuf.c,v 1.1.1.1 2005/04/21 14:56:35 beng Exp $ */

#if     defined(_POSIX_SOURCE)
#include        <sys/types.h>
#endif
#include        <stdio.h>
#include        <stdlib.h>
#include        "loc_incl.h"

ssize_t _read(ssize_t d, char *buf, size_t nbytes);

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 | _IOERR ))) 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++;
}