inftrees.h revision 302408 
138581Sobrien/* inftrees.h -- header to use inftrees.c
238581Sobrien * Copyright (C) 1995-2005 Mark Adler
338581Sobrien * For conditions of distribution and use, see copyright notice in zlib.h
438581Sobrien */
538581Sobrien
650479Speter#pragma ident	"%Z%%M%	%I%	%E% SMI"
738581Sobrien
880029Sobrien/* WARNING: this file should *not* be used by applications. It is
938581Sobrien   part of the implementation of the compression library and is
1080029Sobrien   subject to change. Applications should only use zlib.h.
1180029Sobrien */
1238581Sobrien
13174305Sobrien/* Structure for decoding tables.  Each entry provides either the
14174305Sobrien   information needed to do the operation requested by the code that
15174305Sobrien   indexed that table entry, or it provides a pointer to another
1638581Sobrien   table that indexes more bits of the code.  op indicates whether
17   the entry is a pointer to another table, a literal, a length or
18   distance, an end-of-block, or an invalid code.  For a table
19   pointer, the low four bits of op is the number of index bits of
20   that table.  For a length or distance, the low four bits of op
21   is the number of extra bits to get after the code.  bits is
22   the number of bits in this code or part of the code to drop off
23   of the bit buffer.  val is the actual byte to output in the case
24   of a literal, the base length or distance, or the offset from
25   the current table to the next table.  Each entry is four bytes. */
26typedef struct {
27    unsigned char op;           /* operation, extra bits, table bits */
28    unsigned char bits;         /* bits in this part of the code */
29    unsigned short val;         /* offset in table or code value */
30} code;
31
32/* op values as set by inflate_table():
33    00000000 - literal
34    0000tttt - table link, tttt != 0 is the number of table index bits
35    0001eeee - length or distance, eeee is the number of extra bits
36    01100000 - end of block
37    01000000 - invalid code
38 */
39
40/* Maximum size of dynamic tree.  The maximum found in a long but non-
41   exhaustive search was 1444 code structures (852 for length/literals
42   and 592 for distances, the latter actually the result of an
43   exhaustive search).  The true maximum is not known, but the value
44   below is more than safe. */
45#define ENOUGH 2048
46#define MAXD 592
47
48/* Type of code to build for inftable() */
49typedef enum {
50    CODES,
51    LENS,
52    DISTS
53} codetype;
54
55extern int inflate_table OF((codetype type, unsigned short FAR *lens,
56                             unsigned codes, code FAR * FAR *table,
57                             unsigned FAR *bits, unsigned short FAR *work));
58