1 /*
2 * Copyright © 2015 Intel Corporation
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 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * 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 NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23 #include "util/u_vector.h"
24
25 int
u_vector_init(struct u_vector * vector,uint32_t element_size,uint32_t size)26 u_vector_init(struct u_vector *vector, uint32_t element_size, uint32_t size)
27 {
28 assert(util_is_power_of_two(size));
29 assert(element_size < size && util_is_power_of_two(element_size));
30
31 vector->head = 0;
32 vector->tail = 0;
33 vector->element_size = element_size;
34 vector->size = size;
35 vector->data = malloc(size);
36
37 return vector->data != NULL;
38 }
39
40 void *
u_vector_add(struct u_vector * vector)41 u_vector_add(struct u_vector *vector)
42 {
43 uint32_t offset, size, split, src_tail, dst_tail;
44 void *data;
45
46 if (vector->head - vector->tail == vector->size) {
47 size = vector->size * 2;
48 data = malloc(size);
49 if (data == NULL)
50 return NULL;
51 src_tail = vector->tail & (vector->size - 1);
52 dst_tail = vector->tail & (size - 1);
53 if (src_tail == 0) {
54 /* Since we know that the vector is full, this means that it's
55 * linear from start to end so we can do one copy.
56 */
57 memcpy((char *)data + dst_tail, vector->data, vector->size);
58 } else {
59 /* In this case, the vector is split into two pieces and we have
60 * to do two copies. We have to be careful to make sure each
61 * piece goes to the right locations. Thanks to the change in
62 * size, it may or may not still wrap around.
63 */
64 split = u_align_u32(vector->tail, vector->size);
65 assert(vector->tail <= split && split < vector->head);
66 memcpy((char *)data + dst_tail, (char *)vector->data + src_tail,
67 split - vector->tail);
68 memcpy((char *)data + (split & (size - 1)), vector->data,
69 vector->head - split);
70 }
71 free(vector->data);
72 vector->data = data;
73 vector->size = size;
74 }
75
76 assert(vector->head - vector->tail < vector->size);
77
78 offset = vector->head & (vector->size - 1);
79 vector->head += vector->element_size;
80
81 return (char *)vector->data + offset;
82 }
83
84 void *
u_vector_remove(struct u_vector * vector)85 u_vector_remove(struct u_vector *vector)
86 {
87 uint32_t offset;
88
89 if (vector->head == vector->tail)
90 return NULL;
91
92 assert(vector->head - vector->tail <= vector->size);
93
94 offset = vector->tail & (vector->size - 1);
95 vector->tail += vector->element_size;
96
97 return (char *)vector->data + offset;
98 }
99