/**********************************************************************
*
* 		_ f i l e s z   f u n c t i o n
* 		-------------------------------
*	Copyright 1982 by Digital Research Inc.  All rights reserved.
*
*	This routine computes the size of a CP/M file, and leaves the fd
*	pointing to the end of file.  
*	Note that the file must have been previously opened.
*
*	Calling sequence:
*		size = _filesz(fd)
*	where:
*		size =	# bytes in file;
*			0 if not disk file;
*			-1 if I/O error
*		fd   = file descriptor returned by open.
*
***********************************************************************/
#include <portab.h>
#include <cpm.h>
#include <errno.h>
LONG _filesz(fd)				/****************************/
	WORD fd;				/* file descriptor	    */
{
	REG FD		*fp;			/* file's ccb pointer	    */
	REG BYTE	*p1, *p2;		/* temps for buffer work    */
	REG LONG	xsector;		/* where we are in file	    */
	FD 		*_chkc();		/* cvt & check fd to fp	    */
	LONG 		__BDOS();		/* BDOS fn		    */
						/****************************/
	if((fp = _chkc(fd)) == NULL)		/* Convert to pointer	    */
		return(FAILURE);		/*  Can't		    */
	if(fp->flags&(ISTTY|ISLPT))		/* Non disk file?	    */
		return(0);			/*			    */
	__BDOS(FILSIZ,&(fp->fcb))		/* Do BDOS call		    */
	fp->fcb.record &= 0xFFFFFFL;		/* mask off cr byte	    */
	if( fp->flags & ISASCII )		/****************************/
	{					/* Ascii file: posit to EOF */
	  if(fp->fcb.record > 0)		/* if any size at all	    */
	  {					/*	*********************/
	    xsector = fp->fcb.record - 1;	/* last sector in file      */
	    if( xsector != fp->sector )		/* need to change sector?   */
	    {					/* get correct sector********/
	      if((fp->flags & DIRTY) != 0)	/* Something to write 1st?  */
	      {					/*			    */
	        if(_blkio(fp,fp->sector,fp->buffer, /* Write out	    */
		  1L,B_WRITE) != 1)		/*	the buffer	    */
		    RETERR(FAILURE,EIO);	/*			    */
	        fp->flags &= ~DIRTY;		/* turn off this bit	    */
	      }					/*			    */
	      if(_blkio(fp,xsector,fp->buffer,	/* scan this last sector    */
		  1L,B_READ) != 1)		/*    for EOFCHAR	    */
	        RETERR(FAILURE,EIO);		/*			    */
	    }					/* got correct sector********/
	    fp->sector = xsector;		/* 			    */
	    fp->offset = fp->sector << 7;	/*   			    */
	    p1 = &(fp->buffer[0]);		/* start of buf		    */
	    p2 = &(fp->buffer[SECSIZ]);		/* end of buf		    */
	    while( p1<p2  &&  *p1 != EOFCHAR)	/* look for EOFCHAR	    */
		p1++;				/*			    */
	    fp->offset += p1-&(fp->buffer[0]);	/* update offset to EOF	    */
	  }					/*	*********************/
	  else fp->offset=0;			/* o.w. beginning of file   */
	}					/****************************/
	else 					/* Binary file:compute size */
	  fp->offset = fp->fcb.record << 7;	/* set to end oflast record */
						/****************************/
	fp->hiwater = fp->offset;		/* whatever happened, set it*/
	fp->flags |= ATEOF;			/* make sure they know	    */
	return(fp->offset);			/* this is it		    */
}						/****************************/