1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Range add and subtract
4 */
5#include <linux/init.h>
6#include <linux/minmax.h>
7#include <linux/printk.h>
8#include <linux/sort.h>
9#include <linux/string.h>
10#include <linux/range.h>
11
12int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
13{
14	if (start >= end)
15		return nr_range;
16
17	/* Out of slots: */
18	if (nr_range >= az)
19		return nr_range;
20
21	range[nr_range].start = start;
22	range[nr_range].end = end;
23
24	nr_range++;
25
26	return nr_range;
27}
28
29int add_range_with_merge(struct range *range, int az, int nr_range,
30		     u64 start, u64 end)
31{
32	int i;
33
34	if (start >= end)
35		return nr_range;
36
37	/* get new start/end: */
38	for (i = 0; i < nr_range; i++) {
39		u64 common_start, common_end;
40
41		if (!range[i].end)
42			continue;
43
44		common_start = max(range[i].start, start);
45		common_end = min(range[i].end, end);
46		if (common_start > common_end)
47			continue;
48
49		/* new start/end, will add it back at last */
50		start = min(range[i].start, start);
51		end = max(range[i].end, end);
52
53		memmove(&range[i], &range[i + 1],
54			(nr_range - (i + 1)) * sizeof(range[i]));
55		range[nr_range - 1].start = 0;
56		range[nr_range - 1].end   = 0;
57		nr_range--;
58		i--;
59	}
60
61	/* Need to add it: */
62	return add_range(range, az, nr_range, start, end);
63}
64
65void subtract_range(struct range *range, int az, u64 start, u64 end)
66{
67	int i, j;
68
69	if (start >= end)
70		return;
71
72	for (j = 0; j < az; j++) {
73		if (!range[j].end)
74			continue;
75
76		if (start <= range[j].start && end >= range[j].end) {
77			range[j].start = 0;
78			range[j].end = 0;
79			continue;
80		}
81
82		if (start <= range[j].start && end < range[j].end &&
83		    range[j].start < end) {
84			range[j].start = end;
85			continue;
86		}
87
88
89		if (start > range[j].start && end >= range[j].end &&
90		    range[j].end > start) {
91			range[j].end = start;
92			continue;
93		}
94
95		if (start > range[j].start && end < range[j].end) {
96			/* Find the new spare: */
97			for (i = 0; i < az; i++) {
98				if (range[i].end == 0)
99					break;
100			}
101			if (i < az) {
102				range[i].end = range[j].end;
103				range[i].start = end;
104			} else {
105				pr_err("%s: run out of slot in ranges\n",
106					__func__);
107			}
108			range[j].end = start;
109			continue;
110		}
111	}
112}
113
114static int cmp_range(const void *x1, const void *x2)
115{
116	const struct range *r1 = x1;
117	const struct range *r2 = x2;
118
119	if (r1->start < r2->start)
120		return -1;
121	if (r1->start > r2->start)
122		return 1;
123	return 0;
124}
125
126int clean_sort_range(struct range *range, int az)
127{
128	int i, j, k = az - 1, nr_range = az;
129
130	for (i = 0; i < k; i++) {
131		if (range[i].end)
132			continue;
133		for (j = k; j > i; j--) {
134			if (range[j].end) {
135				k = j;
136				break;
137			}
138		}
139		if (j == i)
140			break;
141		range[i].start = range[k].start;
142		range[i].end   = range[k].end;
143		range[k].start = 0;
144		range[k].end   = 0;
145		k--;
146	}
147	/* count it */
148	for (i = 0; i < az; i++) {
149		if (!range[i].end) {
150			nr_range = i;
151			break;
152		}
153	}
154
155	/* sort them */
156	sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
157
158	return nr_range;
159}
160
161void sort_range(struct range *range, int nr_range)
162{
163	/* sort them */
164	sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
165}
166