linux/kernel/range.c
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   1/*
   2 * Range add and subtract
   3 */
   4#include <linux/kernel.h>
   5#include <linux/init.h>
   6#include <linux/sort.h>
   7#include <linux/string.h>
   8#include <linux/range.h>
   9
  10int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
  11{
  12        if (start >= end)
  13                return nr_range;
  14
  15        /* Out of slots: */
  16        if (nr_range >= az)
  17                return nr_range;
  18
  19        range[nr_range].start = start;
  20        range[nr_range].end = end;
  21
  22        nr_range++;
  23
  24        return nr_range;
  25}
  26
  27int add_range_with_merge(struct range *range, int az, int nr_range,
  28                     u64 start, u64 end)
  29{
  30        int i;
  31
  32        if (start >= end)
  33                return nr_range;
  34
  35        /* get new start/end: */
  36        for (i = 0; i < nr_range; i++) {
  37                u64 common_start, common_end;
  38
  39                if (!range[i].end)
  40                        continue;
  41
  42                common_start = max(range[i].start, start);
  43                common_end = min(range[i].end, end);
  44                if (common_start > common_end)
  45                        continue;
  46
  47                /* new start/end, will add it back at last */
  48                start = min(range[i].start, start);
  49                end = max(range[i].end, end);
  50
  51                memmove(&range[i], &range[i + 1],
  52                        (nr_range - (i + 1)) * sizeof(range[i]));
  53                range[nr_range - 1].start = 0;
  54                range[nr_range - 1].end   = 0;
  55                nr_range--;
  56                i--;
  57        }
  58
  59        /* Need to add it: */
  60        return add_range(range, az, nr_range, start, end);
  61}
  62
  63void subtract_range(struct range *range, int az, u64 start, u64 end)
  64{
  65        int i, j;
  66
  67        if (start >= end)
  68                return;
  69
  70        for (j = 0; j < az; j++) {
  71                if (!range[j].end)
  72                        continue;
  73
  74                if (start <= range[j].start && end >= range[j].end) {
  75                        range[j].start = 0;
  76                        range[j].end = 0;
  77                        continue;
  78                }
  79
  80                if (start <= range[j].start && end < range[j].end &&
  81                    range[j].start < end) {
  82                        range[j].start = end;
  83                        continue;
  84                }
  85
  86
  87                if (start > range[j].start && end >= range[j].end &&
  88                    range[j].end > start) {
  89                        range[j].end = start;
  90                        continue;
  91                }
  92
  93                if (start > range[j].start && end < range[j].end) {
  94                        /* Find the new spare: */
  95                        for (i = 0; i < az; i++) {
  96                                if (range[i].end == 0)
  97                                        break;
  98                        }
  99                        if (i < az) {
 100                                range[i].end = range[j].end;
 101                                range[i].start = end;
 102                        } else {
 103                                pr_err("%s: run out of slot in ranges\n",
 104                                        __func__);
 105                        }
 106                        range[j].end = start;
 107                        continue;
 108                }
 109        }
 110}
 111
 112static int cmp_range(const void *x1, const void *x2)
 113{
 114        const struct range *r1 = x1;
 115        const struct range *r2 = x2;
 116        s64 start1, start2;
 117
 118        start1 = r1->start;
 119        start2 = r2->start;
 120
 121        return start1 - start2;
 122}
 123
 124int clean_sort_range(struct range *range, int az)
 125{
 126        int i, j, k = az - 1, nr_range = az;
 127
 128        for (i = 0; i < k; i++) {
 129                if (range[i].end)
 130                        continue;
 131                for (j = k; j > i; j--) {
 132                        if (range[j].end) {
 133                                k = j;
 134                                break;
 135                        }
 136                }
 137                if (j == i)
 138                        break;
 139                range[i].start = range[k].start;
 140                range[i].end   = range[k].end;
 141                range[k].start = 0;
 142                range[k].end   = 0;
 143                k--;
 144        }
 145        /* count it */
 146        for (i = 0; i < az; i++) {
 147                if (!range[i].end) {
 148                        nr_range = i;
 149                        break;
 150                }
 151        }
 152
 153        /* sort them */
 154        sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
 155
 156        return nr_range;
 157}
 158
 159void sort_range(struct range *range, int nr_range)
 160{
 161        /* sort them */
 162        sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
 163}
 164
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