zlib123/inftrees.h
author Ryan C. Gordon <icculus@icculus.org>
Tue, 11 Apr 2006 14:33:48 +0000
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7zip support, written by Dennis Schridde, and heavily Ryanified by me.
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/* inftrees.h -- header to use inftrees.c
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 * Copyright (C) 1995-2005 Mark Adler
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 * For conditions of distribution and use, see copyright notice in zlib.h
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 */
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/* WARNING: this file should *not* be used by applications. It is
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   part of the implementation of the compression library and is
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   subject to change. Applications should only use zlib.h.
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 */
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/* Structure for decoding tables.  Each entry provides either the
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   information needed to do the operation requested by the code that
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   indexed that table entry, or it provides a pointer to another
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   table that indexes more bits of the code.  op indicates whether
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   the entry is a pointer to another table, a literal, a length or
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   distance, an end-of-block, or an invalid code.  For a table
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   pointer, the low four bits of op is the number of index bits of
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   that table.  For a length or distance, the low four bits of op
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   is the number of extra bits to get after the code.  bits is
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   the number of bits in this code or part of the code to drop off
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   of the bit buffer.  val is the actual byte to output in the case
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   of a literal, the base length or distance, or the offset from
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   the current table to the next table.  Each entry is four bytes. */
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typedef struct {
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    unsigned char op;           /* operation, extra bits, table bits */
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    unsigned char bits;         /* bits in this part of the code */
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    unsigned short val;         /* offset in table or code value */
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} code;
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/* op values as set by inflate_table():
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    00000000 - literal
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    0000tttt - table link, tttt != 0 is the number of table index bits
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    0001eeee - length or distance, eeee is the number of extra bits
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    01100000 - end of block
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    01000000 - invalid code
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 */
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/* Maximum size of dynamic tree.  The maximum found in a long but non-
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   exhaustive search was 1444 code structures (852 for length/literals
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   and 592 for distances, the latter actually the result of an
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   exhaustive search).  The true maximum is not known, but the value
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   below is more than safe. */
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#define ENOUGH 2048
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#define MAXD 592
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/* Type of code to build for inftable() */
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typedef enum {
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    CODES,
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    LENS,
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    DISTS
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} codetype;
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extern int inflate_table OF((codetype type, unsigned short FAR *lens,
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                             unsigned codes, code FAR * FAR *table,
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                             unsigned FAR *bits, unsigned short FAR *work));