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177
mysys/array.c
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177
mysys/array.c
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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA */
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/* Handling of arrays that can grow dynamicly. */
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#if defined(WIN32) || defined(__WIN__)
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#undef SAFEMALLOC /* Problems with threads */
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#endif
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#include "mysys_priv.h"
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#include "m_string.h"
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/*
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Initiate array and alloc space for init_alloc elements. Array is usable
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even if space allocation failed
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*/
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my_bool init_dynamic_array(DYNAMIC_ARRAY *array, uint element_size,
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uint init_alloc, uint alloc_increment)
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{
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DBUG_ENTER("init_dynamic_array");
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if (!alloc_increment)
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{
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alloc_increment=max((8192-MALLOC_OVERHEAD)/element_size,16);
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if (init_alloc > 8 && alloc_increment > init_alloc * 2)
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alloc_increment=init_alloc*2;
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}
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if (!init_alloc)
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init_alloc=alloc_increment;
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array->elements=0;
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array->max_element=init_alloc;
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array->alloc_increment=alloc_increment;
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array->size_of_element=element_size;
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if (!(array->buffer=(char*) my_malloc(element_size*init_alloc,MYF(MY_WME))))
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{
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array->max_element=0;
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DBUG_RETURN(TRUE);
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}
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DBUG_RETURN(FALSE);
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}
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my_bool insert_dynamic(DYNAMIC_ARRAY *array, gptr element)
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{
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gptr buffer;
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if (array->elements == array->max_element)
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{ /* Call only when nessesary */
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if (!(buffer=alloc_dynamic(array)))
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return TRUE;
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}
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else
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{
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buffer=array->buffer+(array->elements * array->size_of_element);
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array->elements++;
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}
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memcpy(buffer,element,(size_t) array->size_of_element);
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return FALSE;
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}
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/* Alloc room for one element */
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byte *alloc_dynamic(DYNAMIC_ARRAY *array)
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{
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if (array->elements == array->max_element)
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{
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char *new_ptr;
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if (!(new_ptr=(char*) my_realloc(array->buffer,(array->max_element+
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array->alloc_increment)*
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array->size_of_element,
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MYF(MY_WME | MY_ALLOW_ZERO_PTR))))
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return 0;
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array->buffer=new_ptr;
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array->max_element+=array->alloc_increment;
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}
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return array->buffer+(array->elements++ * array->size_of_element);
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}
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/* remove last element from array and return it */
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byte *pop_dynamic(DYNAMIC_ARRAY *array)
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{
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if (array->elements)
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return array->buffer+(--array->elements * array->size_of_element);
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return 0;
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}
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my_bool set_dynamic(DYNAMIC_ARRAY *array, gptr element, uint idx)
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{
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if (idx >= array->elements)
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{
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if (idx >= array->max_element)
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{
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uint size;
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char *new_ptr;
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size=(idx+array->alloc_increment)/array->alloc_increment;
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size*= array->alloc_increment;
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if (!(new_ptr=(char*) my_realloc(array->buffer,size*
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array->size_of_element,
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MYF(MY_WME | MY_ALLOW_ZERO_PTR))))
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return TRUE;
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array->buffer=new_ptr;
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array->max_element=size;
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}
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bzero((gptr) (array->buffer+array->elements*array->size_of_element),
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(idx - array->elements)*array->size_of_element);
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array->elements=idx+1;
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}
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memcpy(array->buffer+(idx * array->size_of_element),element,
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(size_t) array->size_of_element);
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return FALSE;
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}
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void get_dynamic(DYNAMIC_ARRAY *array, gptr element, uint idx)
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{
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if (idx >= array->elements)
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{
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DBUG_PRINT("warning",("To big array idx: %d, array size is %d",
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idx,array->elements));
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bzero(element,array->size_of_element);
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return;
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}
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memcpy(element,array->buffer+idx*array->size_of_element,
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(size_t) array->size_of_element);
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}
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void delete_dynamic(DYNAMIC_ARRAY *array)
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{
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if (array->buffer)
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{
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my_free(array->buffer,MYF(MY_WME));
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array->buffer=0;
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array->elements=array->max_element=0;
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}
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}
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void delete_dynamic_element(DYNAMIC_ARRAY *array, uint idx)
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{
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char *ptr=array->buffer+array->size_of_element*idx;
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array->elements--;
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memmove(ptr,ptr+array->size_of_element,
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(array->elements-idx)*array->size_of_element);
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}
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void freeze_size(DYNAMIC_ARRAY *array)
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{
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uint elements=max(array->elements,1);
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if (array->buffer && array->max_element != elements)
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{
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array->buffer=(char*) my_realloc(array->buffer,
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elements*array->size_of_element,
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MYF(MY_WME));
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array->max_element=elements;
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}
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}
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