1 /*
2  * Copyright 2013 Christoph Bumiller
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * on the rights to use, copy, modify, merge, publish, distribute, sub
8  * license, and/or sell copies of the Software, and to permit persons to whom
9  * the Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
21  * USE OR OTHER DEALINGS IN THE SOFTWARE. */
22 
23 #include "nine_helpers.h"
24 
25 static struct nine_range *
26 nine_range_pool_more(struct nine_range_pool *pool)
27 {
28     struct nine_range *r = MALLOC(64 * sizeof(struct nine_range));
29     int i;
30     assert(!pool->free);
31 
32     if (pool->num_slabs == pool->num_slabs_max) {
33         unsigned p = pool->num_slabs_max;
34         unsigned n = pool->num_slabs_max * 2;
35         if (!n)
36             n = 4;
37         pool->slabs = REALLOC(pool->slabs,
38                               p * sizeof(struct nine_range *),
39                               n * sizeof(struct nine_range *));
40         pool->num_slabs_max = n;
41     }
42     pool->free = pool->slabs[pool->num_slabs++] = r;
43 
44     for (i = 0; i < 63; ++i, r = r->next)
45         r->next = (struct nine_range *)
46             ((uint8_t *)r + sizeof(struct nine_range));
47     r->next = NULL;
48 
49     return pool->free;
50 }
51 
52 static inline struct nine_range *
53 nine_range_pool_get(struct nine_range_pool *pool, int16_t bgn, int16_t end)
54 {
55     struct nine_range *r = pool->free;
56     if (!r)
57         r = nine_range_pool_more(pool);
58     assert(r);
59     pool->free = r->next;
60     r->bgn = bgn;
61     r->end = end;
62     return r;
63 }
64 
65 static inline void
66 nine_ranges_coalesce(struct nine_range *r, struct nine_range_pool *pool)
67 {
68     struct nine_range *n;
69 
70     while (r->next && r->end >= r->next->bgn) {
71         n = r->next->next;
72         r->end = (r->end >= r->next->end) ? r->end : r->next->end;
73         nine_range_pool_put(pool, r->next);
74         r->next = n;
75     }
76 }
77 
78 void
79 nine_ranges_insert(struct nine_range **head, int16_t bgn, int16_t end,
80                    struct nine_range_pool *pool)
81 {
82     struct nine_range *r, **pn = head;
83 
84     for (r = *head; r && bgn > r->end; pn = &r->next, r = r->next);
85 
86     if (!r || end < r->bgn) {
87         *pn = nine_range_pool_get(pool, bgn, end);
88         (*pn)->next = r;
89     } else
90     if (bgn < r->bgn) {
91         r->bgn = bgn;
92         if (end > r->end)
93             r->end = end;
94         nine_ranges_coalesce(r, pool);
95     } else
96     if (end > r->end) {
97         r->end = end;
98         nine_ranges_coalesce(r, pool);
99     }
100 }
101