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/* Copyright (c) 2000, 2015, 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 */
/* Handling of arrays that can grow dynamicly. */
#include "mysys_priv.h"
#include "m_string.h"
#include "my_sys.h"
/*
Initiate dynamic array
SYNOPSIS
my_init_dynamic_array()
array Pointer to an array
element_size Size of element
init_buffer Initial buffer pointer
init_alloc Number of initial elements
alloc_increment Increment for adding new elements
DESCRIPTION
init_dynamic_array() initiates array and allocate space for
init_alloc eilements.
Array is usable even if space allocation failed, hence, the
function never returns TRUE.
Static buffers must begin immediately after the array structure.
RETURN VALUE
FALSE Ok
*/
my_bool my_init_dynamic_array(DYNAMIC_ARRAY *array,
PSI_memory_key psi_key,
uint element_size,
void *init_buffer,
uint init_alloc,
uint alloc_increment)
{
DBUG_ENTER("init_dynamic_array");
if (!alloc_increment)
{
alloc_increment=MY_MAX((8192-MALLOC_OVERHEAD)/element_size,16);
if (init_alloc > 8 && alloc_increment > init_alloc * 2)
alloc_increment=init_alloc*2;
}
if (!init_alloc)
{
init_alloc=alloc_increment;
init_buffer= 0;
}
array->elements=0;
array->max_element=init_alloc;
array->alloc_increment=alloc_increment;
array->size_of_element=element_size;
array->m_psi_key= psi_key;
if ((array->buffer= init_buffer))
DBUG_RETURN(FALSE);
/*
Since the dynamic array is usable even if allocation fails here malloc
should not throw an error
*/
if (!(array->buffer= (uchar*) my_malloc(psi_key,
element_size*init_alloc, MYF(0))))
array->max_element=0;
DBUG_RETURN(FALSE);
}
my_bool init_dynamic_array(DYNAMIC_ARRAY *array, uint element_size,
uint init_alloc, uint alloc_increment)
{
/* placeholder to preserve ABI */
return my_init_dynamic_array(array,
PSI_INSTRUMENT_ME,
element_size,
NULL, /* init_buffer */
init_alloc,
alloc_increment);
}
/*
Insert element at the end of array. Allocate memory if needed.
SYNOPSIS
insert_dynamic()
array
element
RETURN VALUE
TRUE Insert failed
FALSE Ok
*/
my_bool insert_dynamic(DYNAMIC_ARRAY *array, const void *element)
{
uchar* buffer;
if (array->elements == array->max_element)
{ /* Call only when nessesary */
if (!(buffer=alloc_dynamic(array)))
return TRUE;
}
else
{
buffer=array->buffer+(array->elements * array->size_of_element);
array->elements++;
}
memcpy(buffer,element,(size_t) array->size_of_element);
return FALSE;
}
/*
Alloc space for next element(s)
SYNOPSIS
alloc_dynamic()
array
DESCRIPTION
alloc_dynamic() checks if there is empty space for at least
one element if not tries to allocate space for alloc_increment
elements at the end of array.
RETURN VALUE
pointer Pointer to empty space for element
0 Error
*/
void *alloc_dynamic(DYNAMIC_ARRAY *array)
{
if (array->elements == array->max_element)
{
char *new_ptr;
if (array->buffer == (uchar *)(array + 1))
{
/*
In this senerio, the buffer is statically preallocated,
so we have to create an all-new malloc since we overflowed
*/
if (!(new_ptr= (char *) my_malloc(array->m_psi_key,
(array->max_element+
array->alloc_increment) *
array->size_of_element,
MYF(MY_WME))))
return 0;
memcpy(new_ptr, array->buffer,
array->elements * array->size_of_element);
}
else
if (!(new_ptr=(char*) my_realloc(array->m_psi_key,
array->buffer,(array->max_element+
array->alloc_increment)*
array->size_of_element,
MYF(MY_WME | MY_ALLOW_ZERO_PTR))))
return 0;
array->buffer= (uchar*) new_ptr;
array->max_element+=array->alloc_increment;
}
return array->buffer+(array->elements++ * array->size_of_element);
}
/*
Pop last element from array.
SYNOPSIS
pop_dynamic()
array
RETURN VALUE
pointer Ok
0 Array is empty
*/
void *pop_dynamic(DYNAMIC_ARRAY *array)
{
if (array->elements)
return array->buffer+(--array->elements * array->size_of_element);
return 0;
}
/*
Get an element from array by given index
SYNOPSIS
get_dynamic()
array
uchar* Element to be returned. If idx > elements contain zeroes.
idx Index of element wanted.
*/
void get_dynamic(DYNAMIC_ARRAY *array, void *element, uint idx)
{
if (idx >= array->elements)
{
DBUG_PRINT("warning",("To big array idx: %d, array size is %d",
idx,array->elements));
memset(element, 0, array->size_of_element);
return;
}
memcpy(element,array->buffer+idx*array->size_of_element,
(size_t) array->size_of_element);
}
void claim_dynamic(DYNAMIC_ARRAY *array)
{
/*
Check for a static buffer
*/
if (array->buffer == (uchar *)(array + 1))
return;
my_claim(array->buffer);
}
/*
Empty array by freeing all memory
SYNOPSIS
delete_dynamic()
array Array to be deleted
*/
void delete_dynamic(DYNAMIC_ARRAY *array)
{
/*
Just mark as empty if we are using a static buffer
*/
if (array->buffer == (uchar *)(array + 1))
array->elements= 0;
else
if (array->buffer)
{
my_free(array->buffer);
array->buffer=0;
array->elements=array->max_element=0;
}
}
/*
Free unused memory
SYNOPSIS
freeze_size()
array Array to be freed
*/
void freeze_size(DYNAMIC_ARRAY *array)
{
uint elements=MY_MAX(array->elements,1);
/*
Do nothing if we are using a static buffer
*/
if (array->buffer == (uchar *)(array + 1))
return;
if (array->buffer && array->max_element != elements)
{
array->buffer=(uchar*) my_realloc(array->m_psi_key,
array->buffer,
elements*array->size_of_element,
MYF(MY_WME));
array->max_element=elements;
}
}
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