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
25int
26u_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
40void *
41u_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
84void *
85u_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