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/* Copyright (C) 2000 MySQL AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 sparce arrays.
The number of elements is limited to 2^16
Every element is aligned to sizeof(element) boundary
(to avoid false sharing if element is big enough).
Actually, it's wait-free, not lock-free ;-)
*/
#undef DBUG_OFF
#include <my_global.h>
#include <strings.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((void *)alloc, MYF(0));
}
else
my_free(alloc[-1], MYF(0));
}
void lf_dynarray_end(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);
bzero(array, sizeof(*array));
}
static const int dynarray_idxes_in_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
};
void *_lf_dynarray_lvalue(LF_DYNARRAY *array, uint idx)
{
void * ptr, * volatile * ptr_ptr=0;
int i;
for (i=3; i > 0; i--)
{
if (ptr_ptr || idx >= dynarray_idxes_in_level[i])
{
if (!ptr_ptr)
{
ptr_ptr=&array->level[i];
idx-= dynarray_idxes_in_level[i];
}
ptr=*ptr_ptr;
if (!ptr)
{
void *alloc=my_malloc(LF_DYNARRAY_LEVEL_LENGTH * sizeof(void *),
MYF(MY_WME|MY_ZEROFILL));
if (!alloc)
return(NULL);
if (my_atomic_casptr(ptr_ptr, &ptr, alloc))
ptr= alloc;
else
my_free(alloc, MYF(0));
}
ptr_ptr=((void **)ptr) + idx / dynarray_idxes_in_level[i];
idx%= dynarray_idxes_in_level[i];
}
}
if (!ptr_ptr)
ptr_ptr=&array->level[0];
ptr=*ptr_ptr;
if (!ptr)
{
void *alloc, *data;
alloc=my_malloc(LF_DYNARRAY_LEVEL_LENGTH * array->size_of_element +
max(array->size_of_element, sizeof(void *)),
MYF(MY_WME|MY_ZEROFILL));
if (!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, MYF(0));
}
return ptr + array->size_of_element * idx;
}
void *_lf_dynarray_value(LF_DYNARRAY *array, uint idx)
{
void * ptr, * volatile * ptr_ptr=0;
int i;
for (i=3; i > 0; i--)
{
if (ptr_ptr || idx >= dynarray_idxes_in_level[i])
{
if (!ptr_ptr)
{
ptr_ptr=&array->level[i];
idx-= dynarray_idxes_in_level[i];
}
ptr=*ptr_ptr;
if (!ptr)
return(NULL);
ptr_ptr=((void **)ptr) + idx / dynarray_idxes_in_level[i];
idx %= dynarray_idxes_in_level[i];
}
}
if (!ptr_ptr)
ptr_ptr=&array->level[0];
ptr=*ptr_ptr;
if (!ptr)
return(NULL);
return 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;
}
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;
}
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