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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/*
Analog of DYNAMIC_ARRAY that never reallocs
(so no pointer into the array may ever become invalid).
Memory is allocated in non-contiguous chunks.
This data structure is not space efficient for sparse arrays.
Every element is aligned to sizeof(element) boundary
(to avoid false sharing if element is big enough).
LF_DYNARRAY is a recursive structure. On the zero level
LF_DYNARRAY::level[0] it's an array of LF_DYNARRAY_LEVEL_LENGTH elements,
on the first level it's an array of LF_DYNARRAY_LEVEL_LENGTH pointers
to arrays of elements, on the second level it's an array of pointers
to arrays of pointers to arrays of elements. And so on.
With four levels the number of elements is limited to 4311810304
(but as in all functions index is uint, the real limit is 2^32-1)
Actually, it's wait-free, not lock-free ;-)
*/
#include <my_global.h>
#include <m_string.h>
#include <my_sys.h>
#include <lf.h>
void lf_dynarray_init(LF_DYNARRAY *array, uint element_size)
{
bzero(array, sizeof(*array));
array->size_of_element= element_size;
my_atomic_rwlock_init(&array->lock);
}
static void recursive_free(void **alloc, int level)
{
if (!alloc)
return;
if (level)
{
int i;
for (i= 0; i < LF_DYNARRAY_LEVEL_LENGTH; i++)
recursive_free(alloc[i], level-1);
my_free(alloc);
}
else
my_free(alloc[-1]);
}
void lf_dynarray_destroy(LF_DYNARRAY *array)
{
int i;
for (i= 0; i < LF_DYNARRAY_LEVELS; i++)
recursive_free(array->level[i], i);
my_atomic_rwlock_destroy(&array->lock);
}
static const ulong dynarray_idxes_in_prev_levels[LF_DYNARRAY_LEVELS]=
{
0, /* +1 here to to avoid -1's below */
LF_DYNARRAY_LEVEL_LENGTH,
LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH +
LF_DYNARRAY_LEVEL_LENGTH,
LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH *
LF_DYNARRAY_LEVEL_LENGTH + LF_DYNARRAY_LEVEL_LENGTH *
LF_DYNARRAY_LEVEL_LENGTH + LF_DYNARRAY_LEVEL_LENGTH
};
static const ulong dynarray_idxes_in_prev_level[LF_DYNARRAY_LEVELS]=
{
0, /* +1 here to to avoid -1's below */
LF_DYNARRAY_LEVEL_LENGTH,
LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH,
LF_DYNARRAY_LEVEL_LENGTH * LF_DYNARRAY_LEVEL_LENGTH *
LF_DYNARRAY_LEVEL_LENGTH,
};
/*
Returns a valid lvalue pointer to the element number 'idx'.
Allocates memory if necessary.
*/
void *_lf_dynarray_lvalue(LF_DYNARRAY *array, uint idx)
{
void * ptr, * volatile * ptr_ptr= 0;
int i;
for (i= LF_DYNARRAY_LEVELS-1; idx < dynarray_idxes_in_prev_levels[i]; i--)
/* no-op */;
ptr_ptr= &array->level[i];
idx-= dynarray_idxes_in_prev_levels[i];
for (; i > 0; i--)
{
if (!(ptr= *ptr_ptr))
{
void *alloc= my_malloc(LF_DYNARRAY_LEVEL_LENGTH * sizeof(void *),
MYF(MY_WME|MY_ZEROFILL));
if (unlikely(!alloc))
return(NULL);
if (my_atomic_casptr(ptr_ptr, &ptr, alloc))
ptr= alloc;
else
my_free(alloc);
}
ptr_ptr= ((void **)ptr) + idx / dynarray_idxes_in_prev_level[i];
idx%= dynarray_idxes_in_prev_level[i];
}
if (!(ptr= *ptr_ptr))
{
uchar *alloc, *data;
alloc= my_malloc(LF_DYNARRAY_LEVEL_LENGTH * array->size_of_element +
MY_MAX(array->size_of_element, sizeof(void *)),
MYF(MY_WME|MY_ZEROFILL));
if (unlikely(!alloc))
return(NULL);
/* reserve the space for free() address */
data= alloc + sizeof(void *);
{ /* alignment */
intptr mod= ((intptr)data) % array->size_of_element;
if (mod)
data+= array->size_of_element - mod;
}
((void **)data)[-1]= alloc; /* free() will need the original pointer */
if (my_atomic_casptr(ptr_ptr, &ptr, data))
ptr= data;
else
my_free(alloc);
}
return ((uchar*)ptr) + array->size_of_element * idx;
}
/*
Returns a pointer to the element number 'idx'
or NULL if an element does not exists
*/
void *_lf_dynarray_value(LF_DYNARRAY *array, uint idx)
{
void * ptr, * volatile * ptr_ptr= 0;
int i;
for (i= LF_DYNARRAY_LEVELS-1; idx < dynarray_idxes_in_prev_levels[i]; i--)
/* no-op */;
ptr_ptr= &array->level[i];
idx-= dynarray_idxes_in_prev_levels[i];
for (; i > 0; i--)
{
if (!(ptr= *ptr_ptr))
return(NULL);
ptr_ptr= ((void **)ptr) + idx / dynarray_idxes_in_prev_level[i];
idx %= dynarray_idxes_in_prev_level[i];
}
if (!(ptr= *ptr_ptr))
return(NULL);
return ((uchar*)ptr) + array->size_of_element * idx;
}
static int recursive_iterate(LF_DYNARRAY *array, void *ptr, int level,
lf_dynarray_func func, void *arg)
{
int res, i;
if (!ptr)
return 0;
if (!level)
return func(ptr, arg);
for (i= 0; i < LF_DYNARRAY_LEVEL_LENGTH; i++)
if ((res= recursive_iterate(array, ((void **)ptr)[i], level-1, func, arg)))
return res;
return 0;
}
/*
Calls func(array, arg) on every array of LF_DYNARRAY_LEVEL_LENGTH elements
in lf_dynarray.
DESCRIPTION
lf_dynarray consists of a set of arrays, LF_DYNARRAY_LEVEL_LENGTH elements
each. _lf_dynarray_iterate() calls user-supplied function on every array
from the set. It is the fastest way to scan the array, faster than
for (i=0; i < N; i++) { func(_lf_dynarray_value(dynarray, i)); }
NOTE
if func() returns non-zero, the scan is aborted
*/
int _lf_dynarray_iterate(LF_DYNARRAY *array, lf_dynarray_func func, void *arg)
{
int i, res;
for (i= 0; i < LF_DYNARRAY_LEVELS; i++)
if ((res= recursive_iterate(array, array->level[i], i, func, arg)))
return res;
return 0;
}
|
