Retro68/hfsutils/darray.c

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2012-03-29 08:28:43 +00:00
/*
* hfsutils - tools for reading and writing Macintosh HFS volumes
* Copyright (C) 1996-1998 Robert Leslie
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: darray.c,v 1.7 1998/11/02 22:08:26 rob Exp $
*/
# ifdef HAVE_CONFIG_H
# include "config.h"
# endif
# include <stdlib.h>
# include <string.h>
# include "darray.h"
struct _darray_ {
char *mem;
size_t memsz;
char *eltend;
size_t elemsz;
};
/*
* NAME: darray->new()
* DESCRIPTION: allocate and return a new dynamic array
*/
darray *darr_new(size_t elemsz)
{
darray *array;
array = malloc(sizeof(darray));
if (array == 0)
return 0;
array->memsz = 8 * elemsz;
array->mem = malloc(array->memsz);
if (array->mem == 0)
{
free(array);
return 0;
}
array->eltend = array->mem;
array->elemsz = elemsz;
return array;
}
/*
* NAME: darray->free()
* DESCRIPTION: dispose of a dynamic array
*/
void darr_free(darray *array)
{
free(array->mem);
free(array);
}
/*
* NAME: darray->size()
* DESCRIPTION: return the number of elements in a dynamic array
*/
unsigned int darr_size(darray *array)
{
return (array->eltend - array->mem) / array->elemsz;
}
/*
* NAME: darray->array()
* DESCRIPTION: return the array as an indexable block
*/
void *darr_array(darray *array)
{
return (void *) array->mem;
}
/*
* NAME: darray->append()
* DESCRIPTION: add an element to the end of a dynamic array
*/
void *darr_append(darray *array, void *elem)
{
char *eltend = array->eltend;
size_t elemsz = array->elemsz;
if ((size_t) (eltend - array->mem) == array->memsz)
{
char *newmem;
size_t newsz;
newsz = array->memsz * 2;
newmem = realloc(array->mem, newsz);
if (newmem == 0)
return 0;
eltend = newmem + array->memsz;
array->mem = newmem;
array->memsz = newsz;
}
memcpy(eltend, elem, elemsz);
array->eltend = eltend + elemsz;
return eltend;
}
/*
* NAME: darray->shrink()
* DESCRIPTION: truncate elements from the end of a dynamic array
*/
void darr_shrink(darray *array, unsigned int nelts)
{
if (nelts < (array->eltend - array->mem) / array->elemsz)
array->eltend = array->mem + nelts * array->elemsz;
}
/*
* NAME: darray->sort()
* DESCRIPTION: arrange items according to sorting criteria
*/
void darr_sort(darray *array, int (*compare)(const void *, const void *))
{
qsort(array->mem, (array->eltend - array->mem) / array->elemsz,
array->elemsz, compare);
}