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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/hash/hashsize.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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*          http://www.eclipse.org/org/documents/epl-v10.html           *

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                 Glenn Fowler <[email protected]>                  *

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*                  David Korn <[email protected]>                   *

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*                   Phong Vo <[email protected]>                    *

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*                                                                      *

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***********************************************************************/

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#pragma prototyped

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/*

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 * Glenn Fowler

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 * AT&T Research

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 *

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 * hash table library

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 */

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#include "hashlib.h"

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/*

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 * change table size and rehash

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 * size must be a power of 2

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 */

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void

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hashsize(register Hash_table_t* tab, int size)

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{

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	register Hash_bucket_t**	old_s;

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	register Hash_bucket_t**	new_s;

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	register Hash_bucket_t*		old_b;

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	register Hash_bucket_t*		new_b;

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	Hash_bucket_t**			old_sx;

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	unsigned int			index;

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	Hash_region_f			region;

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	void*				handle;

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	if (size > 0 && size != tab->size && !(size & (size - 1)))

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	{

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		if (region = tab->root->local->region)

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		{

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			handle = tab->root->local->handle;

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			new_s = (Hash_bucket_t**)(*region)(handle, NiL, sizeof(Hash_bucket_t*) * size, 0);

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		}

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		else new_s = newof(0, Hash_bucket_t*, size, 0);

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		if (!new_s) tab->flags |= HASH_FIXED;

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		else

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		{

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			old_sx = (old_s = tab->table) + tab->size;

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			tab->size = size;

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			while (old_s < old_sx)

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			{

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				old_b = *old_s++;

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				while (old_b)

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				{

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					new_b = old_b;

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					old_b = old_b->next;

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					index = new_b->hash;

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					HASHMOD(tab, index);

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					new_b->next = new_s[index];

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					new_s[index] = new_b;

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				}

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			}

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			if ((tab->flags & (HASH_RESIZE|HASH_STATIC)) != HASH_STATIC)

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			{

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				if (region) (*region)(handle, tab->table, 0, 0);

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				else free(tab->table);

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			}

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			tab->table = new_s;

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			tab->flags |= HASH_RESIZE;

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		}

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	}

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}

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