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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/hash/hashview.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 Bell Laboratories

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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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 * push/pop/query hash table scope

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 *

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 *	bot==0		pop top scope

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 *	bot==top	query

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 *	bot!=0		push top on bot

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 *

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 * scope table pointer returned

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 */

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Hash_table_t*

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hashview(Hash_table_t* top, Hash_table_t* bot)

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{

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	register Hash_bucket_t*		b;

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	register Hash_bucket_t*		p;

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	register Hash_bucket_t**	sp;

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	register Hash_bucket_t**	sx;

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	if (!top || top->frozen)

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		bot = 0;

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	else if (top == bot)

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		bot = top->scope;

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	else if (bot)

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	{

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		if (top->scope)

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			bot = 0;

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		else

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		{

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			sx = &top->table[top->size];

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			sp = &top->table[0];

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			while (sp < sx)

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				for (b = *sp++; b; b = b->next)

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					if (p = (Hash_bucket_t*)hashlook(bot, b->name, HASH_LOOKUP, NiL))

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					{

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						b->name = (p->hash & HASH_HIDES) ? p->name : (char*)b;

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						b->hash |= HASH_HIDES;

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					}

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			top->scope = bot;

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			bot->frozen++;

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		}

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	}

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	else if (bot = top->scope)

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	{

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		sx = &top->table[top->size];

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		sp = &top->table[0];

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		while (sp < sx)

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			for (b = *sp++; b; b = b->next)

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				if (b->hash & HASH_HIDES)

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				{

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					b->hash &= ~HASH_HIDES;

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					b->name = ((Hash_bucket_t*)b->name)->name;

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				}

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		top->scope = 0;

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		bot->frozen--;

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	}

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	return(bot);

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}

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