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CPM OPERATING SYSTEMS/CPM 68K/1.2 SOURCE/6/READ.C

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+/***************************************************************************
+ *									    
+ *			    R e a d   F u n c t i o n			    
+ *			    -------------------------			    
+ *	Copyright 1982 by Digital Research Inc.  All rights reserved.	    
+ *									    
+ *	The read function simulates the UNIX read system call.  Any 	    
+ *	arbitrary number of bytes may be read at any arbitrary offset in    
+ *	the file.							    
+ *	The terminal handler for read has been set up to simulate some of   
+ *	the functions provided by "ioctl".				    
+ *									    
+ *	Edits:								    
+ *		11-Dec-83 whf	Divide into separate files, do PC-DOS I/O   
+ *									    
+ *	Calling Sequence:						    
+ *		ret = read(fd,buffer,bytes);				    
+ *	Where:								    
+ *		ret	Is the number of bytes which were actually read	    
+ *		fd	Is an open file descriptor			    
+ *		buffer	Is the buffer address				    
+ *		bytes	Is the number of bytes to read			    
+ *									    
+ ****************************************************************************/
+
+#include "portab.h"
+#include "osif.h"
+#include "osiferr.h"
+#include "errno.h"
+
+UWORD	read(fd,buff,bytes)			/* CLEAR FUNCTION ***********/
+	WORD	fd;				/* File descriptor	    */
+	BYTE	*buff;				/* -> buffer start	    */
+	UWORD	bytes;				/* =  byte count to read    */
+{						/****************************/
+REG	FD	*fp;				/* -> ccb to read from      */
+	FD	*_chkc();			/* Converts fd to fp	    */
+	UWORD	_ttyin();			/* Read from tty rtn	    */
+	UWORD	_rdasc();			/* Read ascii rtn	    */
+	UWORD	_rdbin();			/* Read binary rtn	    */
+						/****************************/
+	if((fp=_chkc(fd)) == NULLFD)		/* File open & OK??	    */
+		return(FAILURE);		/*	No: EBADF	    */
+	if((fp->flags & ATEOF) != 0)		/* End of file already?	    */
+		return(0);			/* Yes, quit now	    */
+	if((fp->flags & ISLPT) != 0)		/* A wise guy??		    */
+		RETERR(FAILURE,EBADF);		/* 	A wise guy!!	    */
+						/****************************/
+	if((fp->flags & ISTTY) != 0)		/* TTY?			    */
+		return(_ttyin(fp,buff,bytes));	/*	Yes, read 1 line    */
+						/****************************/
+	if(fp->flags & ISASCII)			/* ASCII??		    */
+		return(_rdasc(fp,buff,(LONG)bytes)); /*	Yes, read ascii	    */
+	else	return(_rdbin(fp,buff,(LONG)bytes)); /*	No, read binary	    */
+						/****************************/
+}
+*	No, read binary	    */
+						/****************************/
+}
+*	No, read binary	    */
+						/****************************/
+}