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att
GitHub Repository: att/ast
 Path: blob/master/src/cmd/pack/huffman.h
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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) 1993-2011 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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*                  David Korn <[email protected]>                   *

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*                                                                      *

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

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#pragma prototyped

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/*

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 * Header file for Huffman coding

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 * The coding is the same as that used with the System V pack program

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 *

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 *   David Korn

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 *   AT&T Laboratories

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 */

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#ifndef _HUFFMAN_H_

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#define _HUFFMAN_H_	1

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#include	<ast.h>

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#define HUFFLEV		32	/* maximum number of bits per code */

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#define HUFFMAG1	037	/* ascii <US> */

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#define HUFFMAG2	036	/* ascii <RS> */

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typedef struct

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{

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	char		length[(1<<CHAR_BIT)+1];

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	unsigned char	levcount[HUFFLEV+1];

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	Sfoff_t		insize;

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	Sfoff_t		outsize;

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	long		buffer;

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	long		id;

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	int		left;

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	int		maxlev;

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	int		nchars;

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	int		excess;

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} Huff_t;

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Huff_t*		huffinit(Sfio_t*,Sfoff_t);

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Huff_t*		huffgethdr(Sfio_t*);

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int	 	huffputhdr(Huff_t*,Sfio_t*);

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Sfoff_t		huffencode(Huff_t*,Sfio_t*,Sfio_t*,int);

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Sfoff_t		huffdecode(Huff_t*,Sfio_t*,Sfio_t*,int);

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Sfio_t*		huffdisc(Sfio_t*);

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#define huffend(hp)	free((void*)(hp))

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#define huffisize(hp)	((hp)->insize)

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#define huffosize(hp)	((hp)->outsize)

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#define huffhsize(hp)	((hp)->maxlev+(hp)->nchars+7)

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#endif /* !_HUFFMAN_H_ */

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