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#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include "fdutils.h"
#include "superformat.h"
/* computes the position at the end of this track */
static inline int calc_end_offset(struct params *f, int cur_pos, int *lskew)
{
int sector_skew, byte_skew;
if(cur_pos < f->min) {
/* the current skew is smaller than the extend that this
* sequence can handle. Wait until its beginning */
*lskew = 0;
return f->min + f->length;
}
sector_skew = (cur_pos - f->min + f->chunksize - 1) / f->chunksize;
byte_skew = f->min + sector_skew * f->chunksize;
if(byte_skew >= f->max) {
/* the current skew is larger than the extend that this
* sequence can handle. Wait until its next beginning */
*lskew = 0;
return f->min + f->length + f->raw_capacity;
}
*lskew = sector_skew;
return byte_skew + f->length;
}
static inline void pick_best(struct params *f, int n,
int *min, /* skew in bytes */
int *lskew, /* skew in sectors */
int *min_index)
{
int i,new, t_lskew;
int cur_pos = *min;
for(i = 0 ; i < n; i++) {
new = calc_end_offset(f+i, cur_pos, &t_lskew);
if(i == 0 || new < *min) {
*min = new;
*lskew = t_lskew;
*min_index = i;
}
}
}
/* calc_skews. Fill skew table for use in formatting */
int calc_skews(struct params *fd0, struct params *fd, int n)
{
int cylinder, head;
struct params *f = NULL;
int cur_skew, next_cylinder_skew;
int ind, rots;
/* Amount to advance skew considering head skew already added in */
next_cylinder_skew = cylinder_skew - head_skew;
cur_skew = absolute_skew;
rots = 0;
for (cylinder=begin_cylinder; cylinder <= end_cylinder; ++cylinder) {
for (head=0; head < heads; ++head) {
if (!head && !cylinder && use_2m)
f = fd0;
else
f = fd;
cur_skew = cur_skew % f->raw_capacity;
pick_best(f, n, &cur_skew,
&lskews[cylinder][head],
&findex[cylinder][head]);
rots += cur_skew / f->raw_capacity;
ind = findex[cylinder][head];
if(lskews[cylinder][head] * fd[ind].chunksize >
fd->raw_capacity){
fprintf(stderr,"Skew too big\n");
abort();
}
cur_skew += head_skew;
}
cur_skew += next_cylinder_skew;
}
return 0;
} /* End calc_skews */
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