// SPDX-License-Identifier: GPL-2.0

  /*
   * Range add and subtract
   */

  #include <linux/init.h>

  #include <linux/minmax.h>
  #include <linux/printk.h>

  #include <linux/sort.h>

  #include <linux/string.h>

  #include <linux/range.h>

  int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
  {

  	if (start >= end)

  		return nr_range;
  
  	/* Out of slots: */
  	if (nr_range >= az)
  		return nr_range;
  
  	range[nr_range].start = start;
  	range[nr_range].end = end;
  
  	nr_range++;
  
  	return nr_range;
  }
  
  int add_range_with_merge(struct range *range, int az, int nr_range,
  		     u64 start, u64 end)
  {
  	int i;

  	if (start >= end)

  		return nr_range;

  	/* get new start/end: */

  	for (i = 0; i < nr_range; i++) {

  		u64 common_start, common_end;
  
  		if (!range[i].end)
  			continue;
  
  		common_start = max(range[i].start, start);
  		common_end = min(range[i].end, end);

  		if (common_start > common_end)

  			continue;

  		/* new start/end, will add it back at last */
  		start = min(range[i].start, start);
  		end = max(range[i].end, end);

  		memmove(&range[i], &range[i + 1],
  			(nr_range - (i + 1)) * sizeof(range[i]));
  		range[nr_range - 1].start = 0;
  		range[nr_range - 1].end   = 0;
  		nr_range--;
  		i--;

  	}
  
  	/* Need to add it: */
  	return add_range(range, az, nr_range, start, end);
  }
  
  void subtract_range(struct range *range, int az, u64 start, u64 end)
  {
  	int i, j;

  	if (start >= end)

  		return;
  
  	for (j = 0; j < az; j++) {
  		if (!range[j].end)
  			continue;
  
  		if (start <= range[j].start && end >= range[j].end) {
  			range[j].start = 0;
  			range[j].end = 0;
  			continue;
  		}
  
  		if (start <= range[j].start && end < range[j].end &&

  		    range[j].start < end) {
  			range[j].start = end;

  			continue;
  		}
  
  
  		if (start > range[j].start && end >= range[j].end &&

  		    range[j].end > start) {
  			range[j].end = start;

  			continue;
  		}
  
  		if (start > range[j].start && end < range[j].end) {
  			/* Find the new spare: */
  			for (i = 0; i < az; i++) {
  				if (range[i].end == 0)
  					break;
  			}
  			if (i < az) {
  				range[i].end = range[j].end;

  				range[i].start = end;

  			} else {

  				pr_err("%s: run out of slot in ranges
  ",
  					__func__);

  			}

  			range[j].end = start;

  			continue;
  		}
  	}
  }
  
  static int cmp_range(const void *x1, const void *x2)
  {
  	const struct range *r1 = x1;
  	const struct range *r2 = x2;

  	if (r1->start < r2->start)
  		return -1;
  	if (r1->start > r2->start)
  		return 1;
  	return 0;

  }
  
  int clean_sort_range(struct range *range, int az)
  {

  	int i, j, k = az - 1, nr_range = az;

  
  	for (i = 0; i < k; i++) {
  		if (range[i].end)
  			continue;
  		for (j = k; j > i; j--) {
  			if (range[j].end) {
  				k = j;
  				break;
  			}
  		}
  		if (j == i)
  			break;
  		range[i].start = range[k].start;
  		range[i].end   = range[k].end;
  		range[k].start = 0;
  		range[k].end   = 0;
  		k--;
  	}
  	/* count it */
  	for (i = 0; i < az; i++) {
  		if (!range[i].end) {
  			nr_range = i;
  			break;
  		}
  	}
  
  	/* sort them */
  	sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
  
  	return nr_range;
  }
  
  void sort_range(struct range *range, int nr_range)
  {
  	/* sort them */
  	sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
  }