Upload

Digital Research

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

@@ -0,0 +1,100 @@
+/**************************************************************************
+*
+*			f o p e n   F u n c t i o n
+*			---------------------------
+*	Copyright 1982 by Digital Research Inc.  All rights reserved.
+*
+*	"fopen" opens a buffered stream file, either on disk, console, or
+*	line printer.
+*	Note that "fopen" comes in three (3) flavors, one for ascii CP/M
+*	files, another for binary files, and the default (presently to
+*	ascii files).
+*
+*	Calling sequence:
+*		stream = fopena(name,mode)	(ascii files)
+*		stream = fopenb(name,mode)	(binary files)
+*		stream = fopen(name,mode)	(default-ascii files)
+*		stream = _fopen(name,mode,ascii)
+*	Where:
+*		stream -> file opened (FILE *), NULLPTR if failure
+*		name   -> NULL terminated string containing filename,
+*				name="CON:" means the console,
+*				name="LST:" goes to the line printer, and
+*				otherwise a disk file is assumed.
+*		mode   -> "r" for read only,
+*			  "w" for write only,
+*			  "a" to append (write only) to end of file.
+*		ascii  = 0 if the file is handled as a CP/M text file
+*			(newline -> CRLF xlation, ^Z EOF convention).
+*			Otherwise, file is treated as a binary file.
+*
+*****************************************************************************/
+
+#include "stdio.h"				/****************************/
+#define READ 0					/* read mode val	    */
+#define WRITE 1					/* write mode val	    */
+#define CREATMODE 1				/* mode to use for 'creat'  */
+						/****************************/
+FILE *	_fopen(name,mode,ascii)			/*			    */
+REG	BYTE *name,				/* file name		    */
+	     *mode;				/* "r","w", or "a"	    */
+	BOOLEAN ascii;				/* CP/M text file	    */
+{						/****************************/
+REG	FILE *sp;				/* stream pointer	    */
+REG	WORD ii,				/* index into _iob	    */
+	     fd;				/* file descriptor	    */
+						/****************************/
+	for( ii=0; 				/* look at _iob table	    */
+	    (sp=(&_iob[ii]))->_flag&(_IOREAD|_IOWRT); /* not marked rd/wrt  */
+	    ii++ )				/*			    */
+		if( ii >= MAXFILES )		/* if off end of table	    */
+		    break;			/*			    */
+	if( ii >= MAXFILES )			/*			    */
+		return(NULLFILE);		/*   fail		    */
+	if( *mode == 'w' || *mode == 'W' )	/* 'w'rite mode?	    */
+		fd=_creat(name,CREATMODE,ascii);/*	create file *********/
+	else if( *mode == 'a' || *mode == 'A' )	/* 'a'ppend mode?	    */
+	{					/*			    */
+		if( (fd=_open(name,WRITE,ascii)) < 0 ) /* try open	    */
+			fd=_creat(name,CREATMODE,ascii);/* ow. do create    */
+		else	lseek(fd,0L,2);		/* its out there, seef EOF  */
+	}					/*   ************************/
+	else if( *mode == 'r' || *mode == 'R' )	/* 'r'ead mode?		    */
+		fd=_open(name,READ,ascii);	/*	try open ************/
+	else return(NULLFILE);			/* bad mode barf...	    */
+						/****************************/
+	if(fd<0)				/* did one of those work?   */
+		return(NULLFILE);		/*	no, oh well	    */
+	sp->_cnt = 0;				/* init count		    */
+	sp->_fd = fd;				/*  and file des	    */
+	sp->_base = sp->_ptr = NULLPTR;		/*  and buffer pointers	    */
+	if( *mode == 'r' || *mode == 'R' )	/* 'r'ead mode?		    */
+		sp->_flag = _IOREAD;		/*	say so		    */
+	else	sp->_flag = _IOWRT;		/* else 'w'rite mode	    */
+	if( ascii == 0 )			/* ascii mode?		    */
+		sp->_flag |= _IOASCI;		/*			    */
+						/****************************/
+	return(sp);				/* return the stream ptr    */
+}						/****************************/
+
+						/****************************/
+FILE *	fopen(name,mode)			/* CLEAR FUNCTION ***********/
+	BYTE *name, *mode;			/*			    */
+{						/*			    */
+	return(_fopen(name,mode,0)); 	}	/* ascii file open	    */
+						/****************************/
+FILE *	fopena(name,mode)			/* CLEAR FUNCTION ***********/
+	BYTE *name,*mode;			/*			    */
+{						/*			    */
+	return(_fopen(name,mode,0));	}	/* ascii file open	    */
+						/****************************/
+FILE *	fopenb(name,mode)			/* CLEAR FUNCTION ***********/
+	BYTE *name, *mode;			/*			    */
+{						/*			    */
+	return(_fopen(name,mode,1));	}	/* binary file open	    */
+	    */
+{						/*			    */
+	return(_fopen(name,mode,1));	}	/* binary file open	    */
+	    */
+{						/*			    */
+	return(_fopen(name,mode,1));	}	/* binary file open	    */