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CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102a/clib/xfilbuf.c

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+/****************************************************************************
+*
+*			_ f i l b u f   F u n c t i o n
+*			-------------------------------
+*	Copyright 1982 by Digital Research Inc.  All rights reserved.
+*
+*	"_filbuf" function is called by getc to fill the buffer.
+*	It performs any initialization of the buffered on the first
+*	call.
+*
+*	Calling sequence:
+*		char = _filbuf(stream)
+*	Where:
+*		stream -> file info
+*		char   = the first character returned, or FAILURE (-1)
+*			on error or EOF
+*
+*****************************************************************************/
+#include <stdio.h>
+WORD _filbuf(sp)				/* fill buffer		    */
+REG	FILE *sp;				/* from this stream	    */
+{						/****************************/
+	static BYTE onebuf[MAXFILES];		/* a place if no mem avail. */
+						/* small buf for ungetc	    */
+	EXTERN BYTE *malloc();			/* someplace to get mem	    */
+						/****************************/
+	if((sp->_flag & _IOREAD) == 0)		/* is readable file?	    */
+		return(FAILURE);		/*    no		    */
+	if( sp->_flag & _IOSTRI )		/* is this stream a string? */
+	{					/*    yes: handle EOS as EOF*/
+		sp->_flag |= _IOEOF;		/*			    */
+		return(FAILURE);		/*			    */
+	}					/****************************/
+	if( sp->_base == NULL )			/* has this been done?	    */
+	{					/* no...*********************/
+	    if( sp->_flag & _IONBUF  ||		/* is the No Buf flag set?  */
+		(sp->_base=malloc(BUFSIZ))==NULL) /* can't we get buffer?   */
+		    sp->_flag |= _IONBUF;	/*   set No Buf flag	    */
+	    else    sp->_flag |= _IOABUF;	/* we're all set	    */
+	}					/****************************/
+	if( sp->_flag & _IONBUF )		/* insure this set right    */
+		sp->_base = &onebuf[sp->_fd];	/*   set 'buf' to small buf */
+	if( sp==stdin  &&  (stdout->_flag&_IOLBUF))/* console i/o?	    */
+		fflush(stdout);			/* output whatever to con   */
+	sp->_cnt = read(sp->_fd, sp->_base,	/* read to our buffer	    */
+	    sp->_flag & _IONBUF ? 1 : BUFSIZ);	/*   the right # of bytes   */
+	if( sp->_cnt <= 0 )			/* did read screw up?	    */
+	{					/* yup...********************/
+	    if( sp->_cnt == FAILURE )		/*  really bad?		    */
+		    sp->_flag |= _IOERR|_IOEOF;	/*    say so		    */
+	    else    sp->_flag |= _IOEOF;	/* or just say we can't read*/
+	    return(FAILURE);			/*			    */
+	}					/****************************/
+	sp->_cnt--;				/* take the 1st item	    */
+	sp->_ptr=sp->_base;			/* set up stream	    */
+	return(((WORD)(*sp->_ptr++) & 0377));	/* and return the char	    */
+}						/****************************/