Commit | Line | Data |
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1eb0c69c | 1 | /* |
1eb0c69c MD |
2 | * Static-sized priority heap containing pointers. Based on CLRS, |
3 | * chapter 6. | |
4 | * | |
5 | * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | * | |
7 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
8 | * of this software and associated documentation files (the "Software"), to deal | |
9 | * in the Software without restriction, including without limitation the rights | |
10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
11 | * copies of the Software, and to permit persons to whom the Software is | |
12 | * furnished to do so, subject to the following conditions: | |
13 | * | |
14 | * The above copyright notice and this permission notice shall be included in | |
15 | * all copies or substantial portions of the Software. | |
c462e188 MD |
16 | * |
17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
20 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
23 | * SOFTWARE. | |
1eb0c69c MD |
24 | */ |
25 | ||
3fadfbc0 MJ |
26 | #include <babeltrace2/prio-heap-internal.h> |
27 | #include <babeltrace2/babeltrace-internal.h> | |
28 | #include <babeltrace2/assert-internal.h> | |
1eb0c69c MD |
29 | #include <errno.h> |
30 | #include <stdlib.h> | |
31 | #include <string.h> | |
32 | ||
eacd552c MD |
33 | #ifdef DEBUG_HEAP |
34 | void check_heap(const struct ptr_heap *heap) | |
35 | { | |
36 | size_t i; | |
37 | ||
38 | if (!heap->len) | |
39 | return; | |
40 | ||
41 | for (i = 1; i < heap->len; i++) | |
f6ccaed9 | 42 | BT_ASSERT(!heap->gt(heap->ptrs[i], heap->ptrs[0])); |
eacd552c MD |
43 | } |
44 | #endif | |
45 | ||
557255e5 | 46 | static |
1eb0c69c MD |
47 | size_t parent(size_t i) |
48 | { | |
eacd552c | 49 | return (i - 1) >> 1; |
1eb0c69c MD |
50 | } |
51 | ||
52 | static | |
53 | size_t left(size_t i) | |
54 | { | |
eacd552c | 55 | return (i << 1) + 1; |
1eb0c69c MD |
56 | } |
57 | ||
58 | static | |
59 | size_t right(size_t i) | |
60 | { | |
eacd552c | 61 | return (i << 1) + 2; |
1eb0c69c MD |
62 | } |
63 | ||
557255e5 MD |
64 | /* |
65 | * Copy of heap->ptrs pointer is invalid after heap_grow. | |
66 | */ | |
1eb0c69c MD |
67 | static |
68 | int heap_grow(struct ptr_heap *heap, size_t new_len) | |
69 | { | |
70 | void **new_ptrs; | |
71 | ||
96e1cf26 | 72 | if (likely(heap->alloc_len >= new_len)) |
1eb0c69c MD |
73 | return 0; |
74 | ||
75 | heap->alloc_len = max_t(size_t, new_len, heap->alloc_len << 1); | |
76 | new_ptrs = calloc(heap->alloc_len, sizeof(void *)); | |
96e1cf26 | 77 | if (unlikely(!new_ptrs)) |
1eb0c69c | 78 | return -ENOMEM; |
96e1cf26 | 79 | if (likely(heap->ptrs)) |
1eb0c69c MD |
80 | memcpy(new_ptrs, heap->ptrs, heap->len * sizeof(void *)); |
81 | free(heap->ptrs); | |
82 | heap->ptrs = new_ptrs; | |
83 | return 0; | |
84 | } | |
85 | ||
86 | static | |
87 | int heap_set_len(struct ptr_heap *heap, size_t new_len) | |
88 | { | |
89 | int ret; | |
90 | ||
91 | ret = heap_grow(heap, new_len); | |
96e1cf26 | 92 | if (unlikely(ret)) |
1eb0c69c MD |
93 | return ret; |
94 | heap->len = new_len; | |
95 | return 0; | |
96 | } | |
97 | ||
dd06413f | 98 | int bt_heap_init(struct ptr_heap *heap, size_t alloc_len, |
1eb0c69c MD |
99 | int gt(void *a, void *b)) |
100 | { | |
101 | heap->ptrs = NULL; | |
102 | heap->len = 0; | |
103 | heap->alloc_len = 0; | |
104 | heap->gt = gt; | |
105 | /* | |
106 | * Minimum size allocated is 1 entry to ensure memory allocation | |
dd06413f | 107 | * never fails within bt_heap_replace_max. |
1eb0c69c MD |
108 | */ |
109 | return heap_grow(heap, max_t(size_t, 1, alloc_len)); | |
110 | } | |
111 | ||
dd06413f | 112 | void bt_heap_free(struct ptr_heap *heap) |
1eb0c69c MD |
113 | { |
114 | free(heap->ptrs); | |
115 | } | |
116 | ||
117 | static void heapify(struct ptr_heap *heap, size_t i) | |
118 | { | |
119 | void **ptrs = heap->ptrs; | |
120 | size_t l, r, largest; | |
121 | ||
122 | for (;;) { | |
eacd552c MD |
123 | void *tmp; |
124 | ||
1eb0c69c MD |
125 | l = left(i); |
126 | r = right(i); | |
eacd552c | 127 | if (l < heap->len && heap->gt(ptrs[l], ptrs[i])) |
1eb0c69c MD |
128 | largest = l; |
129 | else | |
130 | largest = i; | |
eacd552c | 131 | if (r < heap->len && heap->gt(ptrs[r], ptrs[largest])) |
1eb0c69c | 132 | largest = r; |
96e1cf26 | 133 | if (unlikely(largest == i)) |
1eb0c69c | 134 | break; |
eacd552c MD |
135 | tmp = ptrs[i]; |
136 | ptrs[i] = ptrs[largest]; | |
137 | ptrs[largest] = tmp; | |
138 | i = largest; | |
1eb0c69c | 139 | } |
eacd552c | 140 | check_heap(heap); |
1eb0c69c MD |
141 | } |
142 | ||
dd06413f | 143 | void *bt_heap_replace_max(struct ptr_heap *heap, void *p) |
1eb0c69c MD |
144 | { |
145 | void *res; | |
1eb0c69c | 146 | |
96e1cf26 | 147 | if (unlikely(!heap->len)) { |
1eb0c69c | 148 | (void) heap_set_len(heap, 1); |
557255e5 | 149 | heap->ptrs[0] = p; |
eacd552c | 150 | check_heap(heap); |
1eb0c69c MD |
151 | return NULL; |
152 | } | |
153 | ||
154 | /* Replace the current max and heapify */ | |
557255e5 MD |
155 | res = heap->ptrs[0]; |
156 | heap->ptrs[0] = p; | |
1eb0c69c MD |
157 | heapify(heap, 0); |
158 | return res; | |
159 | } | |
160 | ||
dd06413f | 161 | int bt_heap_insert(struct ptr_heap *heap, void *p) |
1eb0c69c | 162 | { |
557255e5 MD |
163 | void **ptrs; |
164 | size_t pos; | |
1eb0c69c MD |
165 | int ret; |
166 | ||
167 | ret = heap_set_len(heap, heap->len + 1); | |
96e1cf26 | 168 | if (unlikely(ret)) |
1eb0c69c | 169 | return ret; |
557255e5 | 170 | ptrs = heap->ptrs; |
557255e5 | 171 | pos = heap->len - 1; |
eacd552c MD |
172 | while (pos > 0 && heap->gt(p, ptrs[parent(pos)])) { |
173 | /* Move parent down until we find the right spot */ | |
174 | ptrs[pos] = ptrs[parent(pos)]; | |
175 | pos = parent(pos); | |
557255e5 | 176 | } |
eacd552c MD |
177 | ptrs[pos] = p; |
178 | check_heap(heap); | |
1eb0c69c MD |
179 | return 0; |
180 | } | |
181 | ||
dd06413f | 182 | void *bt_heap_remove(struct ptr_heap *heap) |
1eb0c69c | 183 | { |
1eb0c69c MD |
184 | switch (heap->len) { |
185 | case 0: | |
186 | return NULL; | |
187 | case 1: | |
188 | (void) heap_set_len(heap, 0); | |
557255e5 | 189 | return heap->ptrs[0]; |
1eb0c69c MD |
190 | } |
191 | /* Shrink, replace the current max by previous last entry and heapify */ | |
192 | heap_set_len(heap, heap->len - 1); | |
eacd552c | 193 | /* len changed. previous last entry is at heap->len */ |
dd06413f | 194 | return bt_heap_replace_max(heap, heap->ptrs[heap->len]); |
1eb0c69c MD |
195 | } |
196 | ||
dd06413f | 197 | void *bt_heap_cherrypick(struct ptr_heap *heap, void *p) |
1eb0c69c | 198 | { |
1eb0c69c MD |
199 | size_t pos, len = heap->len; |
200 | ||
201 | for (pos = 0; pos < len; pos++) | |
96e1cf26 | 202 | if (unlikely(heap->ptrs[pos] == p)) |
1eb0c69c MD |
203 | goto found; |
204 | return NULL; | |
205 | found: | |
96e1cf26 | 206 | if (unlikely(heap->len == 1)) { |
1eb0c69c | 207 | (void) heap_set_len(heap, 0); |
eacd552c | 208 | check_heap(heap); |
557255e5 | 209 | return heap->ptrs[0]; |
1eb0c69c MD |
210 | } |
211 | /* Replace p with previous last entry and heapify. */ | |
212 | heap_set_len(heap, heap->len - 1); | |
eacd552c MD |
213 | /* len changed. previous last entry is at heap->len */ |
214 | heap->ptrs[pos] = heap->ptrs[heap->len]; | |
1eb0c69c MD |
215 | heapify(heap, pos); |
216 | return p; | |
217 | } | |
23a151f0 | 218 | |
dd06413f | 219 | int bt_heap_copy(struct ptr_heap *dst, struct ptr_heap *src) |
23a151f0 JD |
220 | { |
221 | int ret; | |
222 | ||
dd06413f | 223 | ret = bt_heap_init(dst, src->alloc_len, src->gt); |
23a151f0 JD |
224 | if (ret < 0) |
225 | goto end; | |
226 | ||
227 | ret = heap_set_len(dst, src->len); | |
228 | if (ret < 0) | |
229 | goto end; | |
230 | ||
231 | memcpy(dst->ptrs, src->ptrs, src->len * sizeof(void *)); | |
232 | ||
233 | end: | |
234 | return ret; | |
235 | } |