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/*
* This file is part of Libsvgtiny
* Licensed under the MIT License,
* http://opensource.org/licenses/mit-license.php
* Copyright 2008 James Bursa <james@semichrome.net>
*/
/**
* A svgtiny_list is a managed array of objects. It grows in chunks to reduce
* calls to realloc(), but keeps wasted space low.
*/
#include <assert.h>
#include <stdlib.h>
#include "svgtiny.h"
#include "svgtiny_internal.h"
struct svgtiny_list {
unsigned int size; /* number of slots used */
unsigned int allocated; /* number of slots allocated (>= size) */
size_t item_size; /* size of each slot / bytes */
char *items; /* array of slots */
};
/**
* Create an empty svgtiny_list.
*/
struct svgtiny_list *svgtiny_list_create(size_t item_size)
{
struct svgtiny_list *list = malloc(sizeof *list);
if (!list)
return 0;
list->size = 0;
list->allocated = 0;
list->item_size = item_size;
list->items = 0;
return list;
}
/**
* Return the number of objects in a list.
*/
unsigned int svgtiny_list_size(struct svgtiny_list *list)
{
return list->size;
}
/**
* Set the number of objects in a list. If the size is increased, the new
* objects are not initialized in any way.
*
* The allocation size formula is taken from Python's list:
* http://svn.python.org/view/python/trunk/Objects/listobject.c?view=markup
*
* Objects may have moved after this call. Use svgtiny_list_get() to get new
* pointers.
*/
svgtiny_code svgtiny_list_resize(struct svgtiny_list *list,
unsigned int new_size)
{
unsigned int new_allocated;
void *new_items;
if (new_size <= list->allocated) {
list->size = new_size;
return svgtiny_OK;
}
new_allocated = (new_size >> 3) + (new_size < 9 ? 3 : 6) + new_size;
if (new_size == 0)
new_allocated = 0;
new_items = realloc(list->items, new_allocated * list->item_size);
if (!new_items)
return svgtiny_OUT_OF_MEMORY;
list->size = new_size;
list->allocated = new_allocated;
list->items = new_items;
return svgtiny_OK;
}
/**
* Return a pointer to an object in a list.
*/
void *svgtiny_list_get(struct svgtiny_list *list,
unsigned int i)
{
assert(i < list->size);
return (void *) (list->items + i * list->item_size);
}
/**
* Add space for one object to a list and return a pointer to it.
*/
void *svgtiny_list_push(struct svgtiny_list *list)
{
svgtiny_code code;
code = svgtiny_list_resize(list, list->size + 1);
if (code != svgtiny_OK)
return 0;
return svgtiny_list_get(list, list->size - 1);
}
/**
* Free an entire list.
*/
void svgtiny_list_free(struct svgtiny_list *list)
{
free(list->items);
free(list);
}
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