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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 "drizzled/internal/my_sys.h"
#include "drizzled/internal/m_string.h"
#include <algorithm>
using namespace std;
namespace drizzled
{
static bool allocate_dynamic(DYNAMIC_ARRAY *array, uint32_t max_elements);
/*
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
*/
bool init_dynamic_array2(DYNAMIC_ARRAY *array, uint32_t element_size,
void *init_buffer, 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 (!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;
if ((array->buffer= (unsigned char*) init_buffer))
return(false);
if (!(array->buffer=(unsigned char*) malloc(element_size*init_alloc)))
{
array->max_element=0;
return(true);
}
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, unsigned char* element)
{
unsigned char* 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
*/
unsigned char *alloc_dynamic(DYNAMIC_ARRAY *array)
{
if (array->elements == 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
*/
if (!(new_ptr= (char *) malloc((array->max_element+
array->alloc_increment) *
array->size_of_element)))
return 0;
memcpy(new_ptr, array->buffer,
array->elements * array->size_of_element);
}
else if (!(new_ptr= (char*) realloc(array->buffer,
(array->max_element+
array->alloc_increment)*
array->size_of_element)))
return 0;
array->buffer= (unsigned char*) 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
*/
unsigned char *pop_dynamic(DYNAMIC_ARRAY *array)
{
if (array->elements)
return array->buffer+(--array->elements * array->size_of_element);
return 0;
}
/*
Replace element in array with given element and index
SYNOPSIS
set_dynamic()
array
element Element to be inserted
idx Index where element is to be inserted
DESCRIPTION
set_dynamic() replaces element in array.
If idx > max_element insert new element. Allocate memory if needed.
RETURN VALUE
true Idx was out of range and allocation of new memory failed
false Ok
*/
bool set_dynamic(DYNAMIC_ARRAY *array, unsigned char* element, uint32_t idx)
{
if (idx >= array->elements)
{
if (idx >= array->max_element && allocate_dynamic(array, idx))
return true;
memset(array->buffer+array->elements*array->size_of_element, 0,
(idx - array->elements)*array->size_of_element);
array->elements=idx+1;
}
memcpy(array->buffer+(idx * array->size_of_element),element,
(size_t) array->size_of_element);
return false;
}
/*
Ensure that dynamic array has enough elements
SYNOPSIS
allocate_dynamic()
array
max_elements Numbers of elements that is needed
NOTES
Any new allocated element are NOT initialized
RETURN VALUE
false Ok
true Allocation of new memory failed
*/
static bool allocate_dynamic(DYNAMIC_ARRAY *array, uint32_t max_elements)
{
if (max_elements >= array->max_element)
{
uint32_t size;
unsigned char *new_ptr;
size= (max_elements + array->alloc_increment)/array->alloc_increment;
size*= array->alloc_increment;
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
*/
if (!(new_ptr= (unsigned char *) malloc(size *
array->size_of_element)))
return 0;
memcpy(new_ptr, array->buffer,
array->elements * array->size_of_element);
}
else
if (!(new_ptr=(unsigned char*) realloc(array->buffer,
size* array->size_of_element)))
return true;
array->buffer= new_ptr;
array->max_element= size;
}
return false;
}
/*
Get an element from array by given index
SYNOPSIS
get_dynamic()
array
unsigned char* Element to be returned. If idx > elements contain zeroes.
idx Index of element wanted.
*/
void get_dynamic(DYNAMIC_ARRAY *array, unsigned char* element, uint32_t idx)
{
if (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);
}
/*
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 == (unsigned char *)(array + 1))
array->elements= 0;
else
if (array->buffer)
{
free(array->buffer);
array->buffer=0;
array->elements=array->max_element=0;
}
}
} /* namespace drizzled */
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