isa-l/igzip/huff_codes.h

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#ifndef HUFF_CODES_H
#define HUFF_CODES_H

#include <immintrin.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include "igzip_lib.h"
#include "bitbuf2.h"

#ifdef _MSC_VER
# include <intrin.h>
#else
# include <x86intrin.h>
#endif

#define LIT_LEN ISAL_DEF_LIT_LEN_SYMBOLS
#define DIST_LEN ISAL_DEF_DIST_SYMBOLS
#define CODE_LEN_CODES 19
#define HUFF_LEN 19
#ifdef LONGER_HUFFTABLE
# define DCODE_OFFSET 26
#else
# define DCODE_OFFSET 0
#endif
#define DYN_HDR_START_LEN 17
#define MAX_HISTHEAP_SIZE LIT_LEN
#define MAX_HUFF_TREE_DEPTH 15
#define D      IGZIP_HIST_SIZE	/* Amount of history */

#define MAX_DEFLATE_CODE_LEN 15
#define MAX_SAFE_LIT_CODE_LEN 13
#define MAX_SAFE_DIST_CODE_LEN 12

#define LONG_DIST_TABLE_SIZE 8192
#define SHORT_DIST_TABLE_SIZE 2
#define LEN_TABLE_SIZE 256
#define LIT_TABLE_SIZE 257
#define LAST_BLOCK 1

#define LEN_EXTRA_BITS_START 264
#define LEN_EXTRA_BITS_INTERVAL 4
#define DIST_EXTRA_BITS_START 3
#define DIST_EXTRA_BITS_INTERVAL 2

#define INVALID_LIT_LEN_HUFFCODE 1
#define INVALID_DIST_HUFFCODE 1
#define INVALID_HUFFCODE 1

#define HASH8K_HASH_MASK  (IGZIP_HASH8K_HASH_SIZE - 1)
#define HASH_HIST_HASH_MASK  (IGZIP_HASH_HIST_SIZE - 1)
#define HASH_MAP_HASH_MASK  (IGZIP_HASH_MAP_HASH_SIZE - 1)

#define LVL0_HASH_MASK  (IGZIP_LVL0_HASH_SIZE - 1)
#define LVL1_HASH_MASK  (IGZIP_LVL1_HASH_SIZE - 1)
#define LVL2_HASH_MASK  (IGZIP_LVL2_HASH_SIZE - 1)
#define LVL3_HASH_MASK  (IGZIP_LVL3_HASH_SIZE - 1)
#define SHORTEST_MATCH  4

#define LENGTH_BITS 5
#define FREQ_SHIFT 16
#define FREQ_MASK_HI (0xFFFFFFFFFFFF0000)
#define DEPTH_SHIFT 24
#define DEPTH_MASK 0x7F
#define DEPTH_MASK_HI (DEPTH_MASK << DEPTH_SHIFT)
#define DEPTH_1       (1 << DEPTH_SHIFT)
#define HEAP_TREE_SIZE (3*MAX_HISTHEAP_SIZE + 1)
#define HEAP_TREE_NODE_START (HEAP_TREE_SIZE-1)
#define MAX_BL_CODE_LEN 7

/**
 * @brief Structure used to store huffman codes
 */
struct huff_code {
	union {
                struct {
                        uint32_t code_and_extra:24;
                        uint32_t length2:8;
                };

		struct {
			uint16_t code;
			uint8_t extra_bit_count;
			uint8_t length;
		};
	};
};

struct tree_node {
	uint32_t child;
	uint32_t depth;
};

struct heap_tree {
	union {
		uint64_t heap[HEAP_TREE_SIZE];
		uint64_t code_len_count[MAX_HUFF_TREE_DEPTH + 1];
		struct tree_node tree[HEAP_TREE_SIZE];
	};
};

struct rl_code {
	uint8_t code;
	uint8_t extra_bits;
};

struct hufftables_icf {
	struct huff_code dist_table[31];
	struct huff_code lit_len_table[513];
};

/**
 * @brief  Returns the deflate symbol value for a repeat length.
*/
uint32_t convert_length_to_len_sym(uint32_t length);

/**
 * @brief  Returns the deflate symbol value for a look back distance.
 */
uint32_t convert_dist_to_dist_sym(uint32_t dist);

/**
 * @brief Determines the code each element of a deflate compliant huffman tree and stores
 * it in a lookup table
 * @requires table has been initialized to already contain the code length for each element.
 * @param table: A lookup table used to store the codes.
 * @param table_length: The length of table.
 * @param count: a histogram representing the number of occurences of codes of a given length
 */
uint32_t set_huff_codes(struct huff_code *table, int table_length, uint32_t * count);

/**
 * @brief Checks if a literal/length huffman table can be stored in the igzip hufftables files.
 * @param table: A literal/length huffman code lookup table.
 * @returns index of the first symbol which fails and 0xFFFF otherwise.
 */
uint16_t valid_lit_huff_table(struct huff_code *huff_code_table);

/**
 * @brief Checks if a distance huffman table can be stored in the igzip hufftables files.
 * @param table: A distance huffman code lookup table.
 * @returnsthe index of the first symbol which fails and 0xFFFF otherwise.
 */
uint16_t valid_dist_huff_table(struct huff_code *huff_code_table);

/**
 * @brief Creates the dynamic huffman deflate header.
 * @returns Returns the  length of header in bits.
 * @requires This function requires header is large enough to store the whole header.
 * @param header: The output header.
 * @param lit_huff_table: A literal/length code huffman lookup table.
 * @param dist_huff_table: A distance huffman code lookup table.
 * @param end_of_block: Value determining whether end of block header is produced or not;
 * 0 corresponds to not end of block and all other inputs correspond to end of block.
 */
int create_header(struct BitBuf2 *header_bitbuf, struct rl_code *huffman_rep, uint32_t length,
		uint64_t * histogram, uint32_t hlit, uint32_t hdist, uint32_t end_of_block);

/**
 * @brief Creates the header for run length encoded huffman trees.
 * @param header: the output header.
 * @param lookup_table: a huffman lookup table.
 * @param huffman_rep: a run length encoded huffman tree.
 * @extra_bits: extra bits associated with the corresponding spot in huffman_rep
 * @param huffman_rep_length: the length of huffman_rep.
 * @param end_of_block: Value determining whether end of block header is produced or not;
 * 0 corresponds to not end of block and all other inputs correspond to end of block.
 * @param hclen: Length of huffman code for huffman codes minus 4.
 * @param hlit: Length of literal/length table minus 257.
 * @parm hdist: Length of distance table minus 1.
 */
int create_huffman_header(struct BitBuf2 *header_bitbuf, struct huff_code *lookup_table,
			  struct rl_code * huffman_rep, uint16_t huffman_rep_length,
			  uint32_t end_of_block, uint32_t hclen, uint32_t hlit,
			  uint32_t hdist);

/**
 * @brief Creates a two table representation of huffman codes.
 * @param code_table: output table containing the code
 * @param code_size_table: output table containing the code length
 * @param length: the lenght of hufftable
 * @param hufftable: a huffman lookup table
 */
void create_code_tables(uint16_t * code_table, uint8_t * code_length_table,
			uint32_t length, struct huff_code *hufftable);

/**
 * @brief Creates a packed representation of length huffman codes.
 * @details In packed_table, bits 32:8 contain the extra bits appended to the huffman
 * code and bits 8:0 contain the code length.
 * @param packed_table: the output table
 * @param length: the length of lit_len_hufftable
 * @param lit_len_hufftable: a literal/length huffman lookup table
 */
void create_packed_len_table(uint32_t * packed_table, struct huff_code *lit_len_hufftable);

/**
 * @brief Creates a packed representation of distance  huffman codes.
 * @details In packed_table, bits 32:8 contain the extra bits appended to the huffman
 * code and bits 8:0 contain the code length.
 * @param packed_table: the output table
 * @param length: the length of lit_len_hufftable
 * @param dist_hufftable: a distance huffman lookup table
 */
void create_packed_dist_table(uint32_t * packed_table, uint32_t length,
			      struct huff_code *dist_hufftable);

/**
 * @brief Checks to see if the hufftable is usable by igzip
 *
 * @param lit_len_hufftable: literal/lenght huffman code
 * @param dist_hufftable: distance huffman code
 * @returns Returns 0 if the table is usable
 */
int are_hufftables_useable(struct huff_code *lit_len_hufftable,
			   struct huff_code *dist_hufftable);

/**
 * @brief Creates a representation of the huffman code from a histogram used to
 * decompress the intermediate compression format.
 *
 * @param bb: bitbuf structure where the header huffman code header is written
 * @param hufftables: output huffman code representation
 * @param hist: histogram used to generat huffman code
 * @param end_of_block: flag whether this is the final huffman code
 *
 * @returns Returns the length in bits of the block with histogram hist encoded
 * with the set hufftable
 */
uint64_t
create_hufftables_icf(struct BitBuf2 *bb, struct hufftables_icf * hufftables,
                  struct isal_mod_hist *hist, uint32_t end_of_block);

#endif