[picodrive.git] / zlib / inftrees.h

/* inftrees.h -- header to use inftrees.c
 * Copyright (C) 1995-2005 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* WARNING: this file should *not* be used by applications. It is
   part of the implementation of the compression library and is
   subject to change. Applications should only use zlib.h.
 */

/* Structure for decoding tables.  Each entry provides either the
   information needed to do the operation requested by the code that
   indexed that table entry, or it provides a pointer to another
   table that indexes more bits of the code.  op indicates whether
   the entry is a pointer to another table, a literal, a length or
   distance, an end-of-block, or an invalid code.  For a table
   pointer, the low four bits of op is the number of index bits of
   that table.  For a length or distance, the low four bits of op
   is the number of extra bits to get after the code.  bits is
   the number of bits in this code or part of the code to drop off
   of the bit buffer.  val is the actual byte to output in the case
   of a literal, the base length or distance, or the offset from
   the current table to the next table.  Each entry is four bytes. */
typedef struct {
    unsigned char op;           /* operation, extra bits, table bits */
    unsigned char bits;         /* bits in this part of the code */
    unsigned short val;         /* offset in table or code value */
} code;

/* op values as set by inflate_table():
    00000000 - literal
    0000tttt - table link, tttt != 0 is the number of table index bits
    0001eeee - length or distance, eeee is the number of extra bits
    01100000 - end of block
    01000000 - invalid code
 */

/* Maximum size of dynamic tree.  The maximum found in a long but non-
   exhaustive search was 1444 code structures (852 for length/literals
   and 592 for distances, the latter actually the result of an
   exhaustive search).  The true maximum is not known, but the value
   below is more than safe. */
#define ENOUGH 2048
#define MAXD 592

/* Type of code to build for inftable() */
typedef enum {
    CODES,
    LENS,
    DISTS
} codetype;

extern int inflate_table OF((codetype type, unsigned short FAR *lens,
                             unsigned codes, code FAR * FAR *table,
                             unsigned FAR *bits, unsigned short FAR *work));
Commit	Line	Data
	1	/* inftrees.h -- header to use inftrees.c
	2	* Copyright (C) 1995-2005 Mark Adler
	3	* For conditions of distribution and use, see copyright notice in zlib.h
	4	*/
	5
	6	/* WARNING: this file should not be used by applications. It is
	7	part of the implementation of the compression library and is
	8	subject to change. Applications should only use zlib.h.
	9	*/
	10
	11	/* Structure for decoding tables. Each entry provides either the
	12	information needed to do the operation requested by the code that
	13	indexed that table entry, or it provides a pointer to another
	14	table that indexes more bits of the code. op indicates whether
	15	the entry is a pointer to another table, a literal, a length or
	16	distance, an end-of-block, or an invalid code. For a table
	17	pointer, the low four bits of op is the number of index bits of
	18	that table. For a length or distance, the low four bits of op
	19	is the number of extra bits to get after the code. bits is
	20	the number of bits in this code or part of the code to drop off
	21	of the bit buffer. val is the actual byte to output in the case
	22	of a literal, the base length or distance, or the offset from
	23	the current table to the next table. Each entry is four bytes. */
	24	typedef struct {
	25	unsigned char op; /* operation, extra bits, table bits */
	26	unsigned char bits; /* bits in this part of the code */
	27	unsigned short val; /* offset in table or code value */
	28	} code;
	29
	30	/* op values as set by inflate_table():
	31	00000000 - literal
	32	0000tttt - table link, tttt != 0 is the number of table index bits
	33	0001eeee - length or distance, eeee is the number of extra bits
	34	01100000 - end of block
	35	01000000 - invalid code
	36	*/
	37
	38	/* Maximum size of dynamic tree. The maximum found in a long but non-
	39	exhaustive search was 1444 code structures (852 for length/literals
	40	and 592 for distances, the latter actually the result of an
	41	exhaustive search). The true maximum is not known, but the value
	42	below is more than safe. */
	43	#define ENOUGH 2048
	44	#define MAXD 592
	45
	46	/* Type of code to build for inftable() */
	47	typedef enum {
	48	CODES,
	49	LENS,
	50	DISTS
	51	} codetype;
	52
	53	extern int inflate_table OF((codetype type, unsigned short FAR *lens,
	54	unsigned codes, code FAR * FAR *table,
	55	unsigned FAR bits, unsigned short FAR work));