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/* Copyright (c) 2000, 2017, 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, version 2.0,
as published by the Free Software Foundation.
This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation. The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.
Without limiting anything contained in the foregoing, this file,
which is part of C Driver for MySQL (Connector/C), is also subject to the
Universal FOSS Exception, version 1.0, a copy of which can be found at
http://oss.oracle.com/licenses/universal-foss-exception.
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, version 2.0, 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 */
/**
@file mysys/array.cc
Handling of arrays that can grow dynamically.
*/
#include <string.h>
#include <sys/types.h>
#include "my_alloc.h"
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_macros.h"
#include "my_sys.h"
#include "mysql/psi/psi_memory.h"
#include "mysql/service_mysql_alloc.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
*/
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("my_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 = static_cast<uchar *>(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);
}
/*
Insert element at the end of array. Allocate memory if needed.
SYNOPSIS
insert_dynamic()
array
element
RETURN VALUE
true Insert failed
false Ok
*/
bool insert_dynamic(DYNAMIC_ARRAY *array, const void *element) {
uchar *buffer;
if (array->elements == array->max_element) { /* Call only when nessesary */
if (!(buffer = static_cast<uchar *>(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;
}
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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