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