Welcome to mirror list, hosted at ThFree Co, Russian Federation.

gsqueue.c « intern « blenlib « blender « source - git.blender.org/blender.git - Unnamed repository; edit this file 'description' to name the repository.
summaryrefslogtreecommitdiff
blob: b09f5113be7e44fc60ea5aaf88bd6a2bdd85876c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/* SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup bli
 *
 * \brief A generic structure queue
 * (a queue for fixed length generally small) structures.
 */

#include <string.h>

#include "MEM_guardedalloc.h"

#include "BLI_gsqueue.h"
#include "BLI_strict_flags.h"
#include "BLI_utildefines.h"

/* target chunk size: 64kb */
#define CHUNK_SIZE_DEFAULT (1 << 16)
/* ensure we get at least this many elems per chunk */
#define CHUNK_ELEM_MIN 32

struct QueueChunk {
  struct QueueChunk *next;
  char data[0];
};

struct _GSQueue {
  struct QueueChunk *chunk_first; /* first active chunk to pop from */
  struct QueueChunk *chunk_last;  /* last active chunk to push onto */
  struct QueueChunk *chunk_free;  /* free chunks to reuse */
  size_t chunk_first_index;       /* index into 'chunk_first' */
  size_t chunk_last_index;        /* index into 'chunk_last' */
  size_t chunk_elem_max;          /* number of elements per chunk */
  size_t elem_size;               /* memory size of elements */
  size_t elem_num;                /* total number of elements */
};

static void *queue_get_first_elem(GSQueue *queue)
{
  return ((char *)(queue)->chunk_first->data) + ((queue)->elem_size * (queue)->chunk_first_index);
}

static void *queue_get_last_elem(GSQueue *queue)
{
  return ((char *)(queue)->chunk_last->data) + ((queue)->elem_size * (queue)->chunk_last_index);
}

/**
 * \return number of elements per chunk, optimized for slop-space.
 */
static size_t queue_chunk_elem_max_calc(const size_t elem_size, size_t chunk_size)
{
  /* get at least this number of elems per chunk */
  const size_t elem_size_min = elem_size * CHUNK_ELEM_MIN;

  BLI_assert((elem_size != 0) && (chunk_size != 0));

  while (UNLIKELY(chunk_size <= elem_size_min)) {
    chunk_size <<= 1;
  }

  /* account for slop-space */
  chunk_size -= (sizeof(struct QueueChunk) + MEM_SIZE_OVERHEAD);

  return chunk_size / elem_size;
}

GSQueue *BLI_gsqueue_new(const size_t elem_size)
{
  GSQueue *queue = MEM_callocN(sizeof(*queue), "BLI_gsqueue_new");

  queue->chunk_elem_max = queue_chunk_elem_max_calc(elem_size, CHUNK_SIZE_DEFAULT);
  queue->elem_size = elem_size;
  /* force init */
  queue->chunk_last_index = queue->chunk_elem_max - 1;

  return queue;
}

static void queue_free_chunk(struct QueueChunk *data)
{
  while (data) {
    struct QueueChunk *data_next = data->next;
    MEM_freeN(data);
    data = data_next;
  }
}

void BLI_gsqueue_free(GSQueue *queue)
{
  queue_free_chunk(queue->chunk_first);
  queue_free_chunk(queue->chunk_free);
  MEM_freeN(queue);
}

void BLI_gsqueue_push(GSQueue *queue, const void *item)
{
  queue->chunk_last_index++;
  queue->elem_num++;

  if (UNLIKELY(queue->chunk_last_index == queue->chunk_elem_max)) {
    struct QueueChunk *chunk;
    if (queue->chunk_free) {
      chunk = queue->chunk_free;
      queue->chunk_free = chunk->next;
    }
    else {
      chunk = MEM_mallocN(sizeof(*chunk) + (queue->elem_size * queue->chunk_elem_max), __func__);
    }

    chunk->next = NULL;

    if (queue->chunk_last == NULL) {
      queue->chunk_first = chunk;
    }
    else {
      queue->chunk_last->next = chunk;
    }

    queue->chunk_last = chunk;
    queue->chunk_last_index = 0;
  }

  BLI_assert(queue->chunk_last_index < queue->chunk_elem_max);

  /* Return last of queue */
  memcpy(queue_get_last_elem(queue), item, queue->elem_size);
}

void BLI_gsqueue_pop(GSQueue *queue, void *r_item)
{
  BLI_assert(BLI_gsqueue_is_empty(queue) == false);

  memcpy(r_item, queue_get_first_elem(queue), queue->elem_size);
  queue->chunk_first_index++;
  queue->elem_num--;

  if (UNLIKELY(queue->chunk_first_index == queue->chunk_elem_max || queue->elem_num == 0)) {
    struct QueueChunk *chunk_free = queue->chunk_first;

    queue->chunk_first = queue->chunk_first->next;
    queue->chunk_first_index = 0;
    if (queue->chunk_first == NULL) {
      queue->chunk_last = NULL;
      queue->chunk_last_index = queue->chunk_elem_max - 1;
    }

    chunk_free->next = queue->chunk_free;
    queue->chunk_free = chunk_free;
  }
}

size_t BLI_gsqueue_len(const GSQueue *queue)
{
  return queue->elem_num;
}

bool BLI_gsqueue_is_empty(const GSQueue *queue)
{
  return (queue->chunk_first == NULL);
}