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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; 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 <config.h>
#include <algorithm>
#include <drizzled/dynamic_array.h>
#include <drizzled/internal/my_sys.h>
using namespace std;
namespace drizzled {
/*
Initiate dynamic array
SYNOPSIS
init_dynamic_array2()
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.
Static buffers must begin immediately after the array structure.
RETURN VALUE
true malloc() failed
false Ok
*/
static void init_dynamic_array2(DYNAMIC_ARRAY* array, uint32_t element_size, uint32_t init_alloc, uint32_t alloc_increment)
{
if (!alloc_increment)
{
alloc_increment= max((8192 - MALLOC_OVERHEAD) / element_size, 16U);
if (init_alloc > 8 && alloc_increment > init_alloc * 2)
alloc_increment= init_alloc * 2;
}
if (not init_alloc)
init_alloc= alloc_increment;
array->set_size(0);
array->max_element= init_alloc;
array->alloc_increment= alloc_increment;
array->size_of_element= element_size;
array->buffer= (unsigned char*) malloc(element_size * init_alloc);
}
void DYNAMIC_ARRAY::init(uint32_t element_size, uint32_t init_alloc, uint32_t alloc_increment0)
{
init_dynamic_array2(this, element_size, init_alloc, alloc_increment0);
}
/*
Insert element at the end of array. Allocate memory if needed.
SYNOPSIS
insert_dynamic()
array
element
RETURN VALUE
true Insert failed
false Ok
*/
static void insert_dynamic(DYNAMIC_ARRAY* array, void* element)
{
unsigned char* buffer;
if (array->size() == array->max_element)
buffer= array->alloc();
else
{
buffer= array->buffer+(array->size() * array->size_of_element);
array->set_size(array->size() + 1);
}
memcpy(buffer,element, array->size_of_element);
}
void DYNAMIC_ARRAY::push_back(void* v)
{
insert_dynamic(this, v);
}
/*
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
*/
static unsigned char* alloc_dynamic(DYNAMIC_ARRAY* array)
{
if (array->size() == array->max_element)
{
char* new_ptr;
if (array->buffer == (unsigned char*)(array + 1))
{
/*
In this senerio, the buffer is statically preallocated,
so we have to create an all-new malloc since we overflowed
*/
new_ptr= (char*) malloc((array->max_element + array->alloc_increment) * array->size_of_element);
memcpy(new_ptr, array->buffer, array->size() * array->size_of_element);
}
else
new_ptr= (char*) realloc(array->buffer, (array->max_element + array->alloc_increment) * array->size_of_element);
array->buffer= (unsigned char*) new_ptr;
array->max_element+=array->alloc_increment;
}
array->set_size(array->size() + 1);
return array->buffer + ((array->size() - 1) * array->size_of_element);
}
unsigned char* DYNAMIC_ARRAY::alloc()
{
return alloc_dynamic(this);
}
/*
Empty array by freeing all memory
SYNOPSIS
delete_dynamic()
array Array to be deleted
*/
static void delete_dynamic(DYNAMIC_ARRAY* array)
{
/*
Just mark as empty if we are using a static buffer
*/
if (array->buffer == (unsigned char*)(array + 1))
array->set_size(0);
else if (array->buffer)
{
free(array->buffer);
array->buffer=0;
array->set_size(array->max_element=0);
}
}
void DYNAMIC_ARRAY::free()
{
delete_dynamic(this);
}
} /* namespace drizzled */
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