#ifndef _WIMLIB_LZMS_H
#define _WIMLIB_LZMS_H

/* Constants for the LZMS data compression format.  See the comments in
 * lzms-decompress.c for more information about this format.  */

//#define ENABLE_LZMS_DEBUG
#ifdef ENABLE_LZMS_DEBUG
#	define LZMS_DEBUG DEBUG
#       define LZMS_ASSERT wimlib_assert
#else
#	define LZMS_DEBUG(format, ...)
#	define LZMS_ASSERT(...)
#endif

#define LZMS_NUM_RECENT_OFFSETS			3

#define LZMS_PROBABILITY_BITS			6
#define LZMS_PROBABILITY_MAX			(1U << LZMS_PROBABILITY_BITS)
#define LZMS_INITIAL_PROBABILITY		48
#define LZMS_INITIAL_RECENT_BITS		0x0000000055555555ULL

#define LZMS_NUM_MAIN_STATES			16
#define LZMS_NUM_MATCH_STATES			32
#define LZMS_NUM_LZ_MATCH_STATES		64
#define LZMS_NUM_LZ_REPEAT_MATCH_STATES		64
#define LZMS_NUM_DELTA_MATCH_STATES		64
#define LZMS_NUM_DELTA_REPEAT_MATCH_STATES	64
#define LZMS_MAX_NUM_STATES			64

#define LZMS_NUM_LITERAL_SYMS			256
#define LZMS_NUM_LEN_SYMS			54
#define LZMS_NUM_DELTA_POWER_SYMS		8
#define LZMS_MAX_NUM_OFFSET_SYMS		799
#define LZMS_MAX_NUM_SYMS			799

#define LZMS_MAX_CODEWORD_LEN			15

#define LZMS_LITERAL_CODE_REBUILD_FREQ		1024
#define LZMS_LZ_OFFSET_CODE_REBUILD_FREQ	1024
#define LZMS_LENGTH_CODE_REBUILD_FREQ		512
#define LZMS_DELTA_OFFSET_CODE_REBUILD_FREQ	1024
#define LZMS_DELTA_POWER_CODE_REBUILD_FREQ	512

#define LZMS_X86_MAX_GOOD_TARGET_OFFSET		65535
#define LZMS_X86_MAX_TRANSLATION_OFFSET		1023

/* Code shared between the LZMS decompressor and compressor.  */

#include <wimlib/types.h>

extern void
lzms_x86_filter(u8 data[], s32 size, s32 last_target_usages[], bool undo);

/* Probability entry for use by the range coder when in a specific state.  */
struct lzms_probability_entry {

	/* Number of zeroes in the most recent LZMS_PROBABILITY_MAX bits that
	 * have been coded using this probability entry.  This is a cached value
	 * because it can be computed as LZMS_PROBABILITY_MAX minus the Hamming
	 * weight of the low-order LZMS_PROBABILITY_MAX bits of @recent_bits.
	 * */
	u32 num_recent_zero_bits;

	/* The most recent LZMS_PROBABILITY_MAX bits that have been coded using
	 * this probability entry.  The size of this variable, in bits, must be
	 * at least LZMS_PROBABILITY_MAX.  */
	u64 recent_bits;
};

/* LRU queues for LZ matches.  */
struct lzms_lz_lru_queues {

        /* Recent LZ match offsets  */
	u32 recent_offsets[LZMS_NUM_RECENT_OFFSETS + 1];

        /* These variables are used to delay updates to the LRU queues by one
         * decoded item.  */
	u32 prev_offset;
	u32 upcoming_offset;
};

/* LRU queues for delta matches.  */
struct lzms_delta_lru_queues {

        /* Recent delta match powers and offsets  */
	u32 recent_powers[LZMS_NUM_RECENT_OFFSETS + 1];
	u32 recent_offsets[LZMS_NUM_RECENT_OFFSETS + 1];

        /* These variables are used to delay updates to the LRU queues by one
         * decoded item.  */
	u32 prev_power;
	u32 prev_offset;
	u32 upcoming_power;
	u32 upcoming_offset;
};

/* LRU (least-recently-used) queues for match information.  */
struct lzms_lru_queues {
        struct lzms_lz_lru_queues lz;
        struct lzms_delta_lru_queues delta;
};

extern u32 lzms_position_slot_base[LZMS_MAX_NUM_OFFSET_SYMS + 1];

extern u32 lzms_length_slot_base[LZMS_NUM_LEN_SYMS + 1];

extern void
lzms_init_slot_bases(void);

extern u32
lzms_get_slot(u32 value, const u32 slot_base_tab[], unsigned num_slots);

static inline u32
lzms_get_position_slot(u32 value)
{
	return lzms_get_slot(value, lzms_position_slot_base,
			     LZMS_MAX_NUM_OFFSET_SYMS);
}

static inline u32
lzms_get_length_slot(u32 value)
{
	return lzms_get_slot(value, lzms_length_slot_base,
			     LZMS_NUM_LEN_SYMS);
}

extern void
lzms_init_lru_queues(struct lzms_lru_queues *lru);

extern void
lzms_update_lru_queues(struct lzms_lru_queues *lru);

#endif /* _WIMLIB_LZMS_H  */