/* zero.c */

/* 16-Mar-88  ml.	split up assist.c into this and markbad.c	*/
/* 11-Dec-87  ml.	added BSL concept to zero().			*/
/* 01-Nov-88  jye.  change add codes so that can be used for MS-DOS */


#include "osbind.h"
#include "obdefs.h"
#include "mydefs.h"
#include "part.h"
#include "bsl.h"
#include "addr.h"


extern long gbslsiz();
extern long bslsiz;
extern BYTE *bsl;
extern long ratio;


/*           
 * Zero logical dev
 *
 */
zero(ldev)
int ldev;
{
    UWORD pdev,ndirs, fatsiz;
	UWORD bps, sects;
    SECTOR fat0, data, size, dummy=0;
    char bs[512];
    char *newbs;
    BOOT *boot;
    int  bootsiz, i, ret;
	char *buf1;
	long remsect;
	long datsect;
	long datclst; 
	long fatclst;
	long entsect;
	long nsect;
    
    if ((ret = rdsects(ldev, 1, bs, (SECTOR)0)) != 0) {
    	if (tsterr(ret) != OK)
	    	err(bootread);
		return ERROR;
    }

    /*
     * Zero file system's boot sector, FAT and DIR sectors.
     */
    boot = (BOOT *)bs;
    gw((UWORD *)&boot->b_ndirs[0], &ndirs);
    gw((UWORD *)&boot->b_spf[0], &fatsiz);
    gw((UWORD *)&boot->b_bps[0], &bps);
    gw((UWORD *)&boot->b_nsects[0], &sects);
	nsect = (long)sects;
	ratio = (long)(bps / BPS);
	size = (long)BPS * ratio;
	if ((newbs = (char *)Malloc(size)) <= 0)	{
		err(nomemory);
		if (newbs > 0) Mfree((long)newbs);
		return ERROR;
	}
    
    if ((ret = zerosect(ldev, (SECTOR)0, 
					(1 + fatsiz*2 + ndirs*BPDIR/bps)*((UWORD)ratio))) != 0) {
    	if (tsterr(ret) != OK)
            err(hdrwrite);
        return ERROR;
    }
	     

    /* Put boot information into new boot sector */
    if ((ret = rdsects(ldev, (UWORD)ratio, newbs, (SECTOR)0)) != 0) {
    	if (tsterr(ret) != OK)
            err(bootread);
        return ERROR;
    }
    bootsiz = sizeof(BOOT);        
    for (i = 0; i < bootsiz; i++)
        newbs[i] = bs[i];
    
	/* put the last long word data into the new boot sector */
	*(long *)&newbs[508] = *(long *)&bs[508];

    /* Write boot information back to disk */
    if ((ret = wrsects(ldev, (UWORD)ratio, newbs, (SECTOR)0)) != 0) {
    	if (tsterr(ret) != OK)
            err(bootwrit);
        return ERROR;
    }
        

	/* # of sectors in datas:  
	 *			 	datsect   = nsect - boot - 2*fatsiz - size of dir 
	 * 						  = nsect-boot-2*fatsiz-(ndirs*BPDIR)/bps
	 * # of clusters in datas: 
	 *				datclst	  = # of sectors in datas / SPC 
	 * # of clusters(entries) in Fat: 
	 *				fatclst   = fatsiz * (bps/2)
	 * # of sectors need in fat talbe for datclst:
	 *				entsect   = datclst / (bps/2)
	 * # of sectors need to remodify to 0xffff:
	 *				remsect   = fatsiz - entsect
	 */

	datsect = nsect - 1 - 2*fatsiz - (ndirs*BPDIR)/bps;
	datclst = datsect / SPC;
	fatclst = (long)fatsiz * (bps/2);
	entsect = datclst / (bps/2);
	remsect = ((long)fatsiz - entsect)*size;


	/* # of sectors need to remodify to 0xffff */
	if ((buf1 = (char *)Malloc(remsect)) <= 0)	{
		err(nomemory);
		if (newbs > 0) Mfree((long)newbs);
		if (buf1 > 0) Mfree((long)buf1);
		return ERROR;
	}

	/* 
	 * Apr-23-93 jye: To fixed the write over to next partitiona in the Gemdos  
	 *				  , here just set those entries in Fat table, which don't
	 *				  correspond to the availble date sectors in the partition.
	 *				  The pointers should be:
	 *				  	(boot+datclst/(bps/2))*ratio and 
	 *					(boot+fatsiz+datclst/(bps/2))*ratio 
	 */
	if ((ret = rdsects(ldev, (UWORD)(remsect/BPS), buf1, 
	 					(1+datclst/(bps/2))*ratio)) != OK) {
	    if (tsterr(ret) != OK)
	        err(bootwrit);
	    return ERROR;
	}
	/* fill the last sectors of FAT start at last entry with the 0xffff */
	/* +2 is for the two reserved entries in the fat table */
	fillfat(buf1, ((datclst % (bps/2))+2)*2, remsect, 0xffff);
	if ((ret = wrsects(ldev,(UWORD)(remsect/BPS),buf1,
	 						(1+datclst/(bps/2))*ratio) != OK) ||
		(ret = wrsects(ldev,(UWORD)(remsect/BPS),buf1,
	 						(1+fatsiz+datclst/(bps/2))*ratio) != OK)) {
	    if (tsterr(ret) != OK)
	        err(bootwrit);
	    return ERROR;
	}
	/* Apr-23-93 jye: Add above codes to fix the Gemdos over write next
	 * 				  partition.
	 */

		     

    /*
     * Make first 2 entries in FATs more IBM-like.
     */
    if ((ret = rdsects(ldev,(UWORD)ratio,newbs,ratio)) != 0) {/* read FAT 0 */
		return ERROR;
    }
    *(UWORD *)&newbs[0] = 0xf8ff;
    *(UWORD *)&newbs[2] = 0xffff;
    
    /* write FAT 0 and FAT 1 */
    if ((ret = wrsects(ldev, (UWORD)ratio, newbs, ratio)) != 0
	|| (ret = wrsects(ldev, (UWORD)ratio, newbs, 
				(SECTOR)((1+fatsiz)*ratio))) != 0) {
	if (tsterr(ret) != OK)
	    err(fatwrite);
	return ERROR;
    }
	    
    pdev = ldev;
    log2phys(&pdev, &dummy);
    
    /* Get size of BSL */
    if ((bslsiz = gbslsiz(pdev)) > 0L) {
    	/* Allocate memory for existing BSL */
    	if ((bsl = (BYTE *)mymalloc((int)bslsiz << 9)) <= 0)
    	    return err(nomemory);
    	    
    	/* Read in BSL */
    	if ((dummy = rdbsl(pdev)) != OK) {
    	    free(bsl);
    	    if (dummy = INVALID)
    	        err(cruptbsl);
    	    return ERROR;
    	}
    	
	fat0 = ratio;
	data = (SECTOR)1 + (SECTOR)fatsiz*2 + (SECTOR)(ndirs*BPDIR/bps);
	
        /* Mark Vendor or User Bad Sectors into FAT */
	if (bsl2fat(ldev, fat0, fatsiz*((UWORD)ratio), data*ratio, MEDIA) != OK) {
            free(bsl);
            return ERROR;
        }
	free(bsl);
    }
	if (newbs > 0)	Mfree((long)newbs);
	if (buf1 > 0) Mfree((long)buf1);
    return OK;
}