Adaptive probability tables and state used by LZMA. More...

#include <xz.hpp>

Classes
struct	length_model
	Probability tables for the three LZMA match-length ranges. More...

Public Member Functions
void	reset ()
	Reset the probability model and recent-match state.

void	set_properties (std::uint8_t properties)
	Configures lc, lp, and pb from one LZMA properties byte.

Public Attributes
std::uint32_t	rep0 = 0U
	Most recent repeated match distance minus one.

std::uint32_t	rep1 = 0U
	Second most recent repeated distance minus one.

std::uint32_t	rep2 = 0U
	Third most recent repeated distance minus one.

std::uint32_t	rep3 = 0U
	Fourth most recent repeated distance minus one.

std::uint8_t	state = 0U
	Current LZMA literal/match state.

std::uint8_t	literal_context_bits = 3U
	Number of high previous-byte bits in a literal context.

std::uint8_t	literal_position_bits = 0U
	Number of low position bits in a literal context.

std::uint8_t	position_bits = 2U
	Number of low position bits selecting a position state.

std::array< std::array< std::uint16_t, position_state_count >, state_count >	is_match {}
	Literal-versus-match probabilities.

std::array< std::uint16_t, state_count >	is_rep {}
	New-versus-repeated match probabilities.

std::array< std::uint16_t, state_count >	is_rep0 {}
	Most-recent-distance probabilities.

std::array< std::uint16_t, state_count >	is_rep1 {}
	Second-distance probabilities.

std::array< std::uint16_t, state_count >	is_rep2 {}
	Third-versus-fourth distance probabilities.

std::array< std::array< std::uint16_t, position_state_count >, state_count >	is_rep0_long {}
	Short repeated-match probabilities.

std::array< std::array< std::uint16_t, 64U >, 4U >	distance_slot {}
	Distance-slot trees by match-length state.

std::array< std::uint16_t, 114U >	distance_special {}
	Probability trees for middle distance bits.

std::array< std::uint16_t, 16U >	distance_align {}
	Reversed tree for low aligned distance bits.

length_model	match_length
	Length model for new matches.

length_model	repeated_length
	Length model for repeated matches.

std::array< std::array< std::uint16_t, literal_coder_size >, literal_coder_count >	literal {}
	Literal probability trees by context.

Detailed Description

Adaptive probability tables and state used by LZMA.

Definition at line 51 of file xz.hpp.

Member Function Documentation

◆ reset()

void rpnx::compression::xz_codec::lzma_model::reset ( )

inline

Reset the probability model and recent-match state.

Definition at line 85 of file xz.hpp.

References rep0, rep1, rep2, rep3, and state.

Referenced by rpnx::compression::xz_codec::decompress(), and set_properties().

◆ set_properties()

void rpnx::compression::xz_codec::lzma_model::set_properties ( std::uint8_t properties )

inline

Configures lc, lp, and pb from one LZMA properties byte.

Parameters

properties Encoded LZMA lc/lp/pb value.

Exceptions

compression_error If the value or supported context sum is invalid.

Definition at line 100 of file xz.hpp.

References rpnx::compression::invalid_data, literal_context_bits, literal_position_bits, position_bits, reset(), and rpnx::compression::xz.

Referenced by rpnx::compression::xz_codec::compress(), and rpnx::compression::xz_codec::decompress().

Member Data Documentation

◆ distance_align

std::array< std::uint16_t, 16U > rpnx::compression::xz_codec::lzma_model::distance_align {}

Reversed tree for low aligned distance bits.

Definition at line 79 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ distance_slot

std::array< std::array< std::uint16_t, 64U >, 4U > rpnx::compression::xz_codec::lzma_model::distance_slot {}

Distance-slot trees by match-length state.

Definition at line 77 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ distance_special

std::array< std::uint16_t, 114U > rpnx::compression::xz_codec::lzma_model::distance_special {}

Probability trees for middle distance bits.

Definition at line 78 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ is_match

std::array< std::array< std::uint16_t, position_state_count >, state_count > rpnx::compression::xz_codec::lzma_model::is_match {}

Literal-versus-match probabilities.

Definition at line 71 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::compress_lzma_literals(), and rpnx::compression::xz_codec::decode_lzma_chunk().

◆ is_rep

std::array< std::uint16_t, state_count > rpnx::compression::xz_codec::lzma_model::is_rep {}

New-versus-repeated match probabilities.

Definition at line 72 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ is_rep0

std::array< std::uint16_t, state_count > rpnx::compression::xz_codec::lzma_model::is_rep0 {}

Most-recent-distance probabilities.

Definition at line 73 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ is_rep0_long

std::array< std::array< std::uint16_t, position_state_count >, state_count > rpnx::compression::xz_codec::lzma_model::is_rep0_long {}

Short repeated-match probabilities.

Definition at line 76 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ is_rep1

std::array< std::uint16_t, state_count > rpnx::compression::xz_codec::lzma_model::is_rep1 {}

Second-distance probabilities.

Definition at line 74 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ is_rep2

std::array< std::uint16_t, state_count > rpnx::compression::xz_codec::lzma_model::is_rep2 {}

Third-versus-fourth distance probabilities.

Definition at line 75 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ literal

std::array< std::array< std::uint16_t, literal_coder_size >, literal_coder_count > rpnx::compression::xz_codec::lzma_model::literal {}

Literal probability trees by context.

Definition at line 82 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::compress_lzma_literals(), and rpnx::compression::xz_codec::decode_lzma_chunk().

◆ literal_context_bits

std::uint8_t rpnx::compression::xz_codec::lzma_model::literal_context_bits = 3U

Number of high previous-byte bits in a literal context.

Definition at line 68 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::compress_lzma_literals(), rpnx::compression::xz_codec::decode_lzma_chunk(), and set_properties().

◆ literal_position_bits

std::uint8_t rpnx::compression::xz_codec::lzma_model::literal_position_bits = 0U

Number of low position bits in a literal context.

Definition at line 69 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::compress_lzma_literals(), rpnx::compression::xz_codec::decode_lzma_chunk(), and set_properties().

◆ match_length

length_model rpnx::compression::xz_codec::lzma_model::match_length

Length model for new matches.

Definition at line 80 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ position_bits

std::uint8_t rpnx::compression::xz_codec::lzma_model::position_bits = 2U

Number of low position bits selecting a position state.

Definition at line 70 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::compress_lzma_literals(), rpnx::compression::xz_codec::decode_lzma_chunk(), and set_properties().

◆ rep0

std::uint32_t rpnx::compression::xz_codec::lzma_model::rep0 = 0U

Most recent repeated match distance minus one.

Definition at line 63 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk(), and reset().

◆ rep1

std::uint32_t rpnx::compression::xz_codec::lzma_model::rep1 = 0U

Second most recent repeated distance minus one.

Definition at line 64 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk(), and reset().

◆ rep2

std::uint32_t rpnx::compression::xz_codec::lzma_model::rep2 = 0U

Third most recent repeated distance minus one.

Definition at line 65 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk(), and reset().

◆ rep3

std::uint32_t rpnx::compression::xz_codec::lzma_model::rep3 = 0U

Fourth most recent repeated distance minus one.

Definition at line 66 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk(), and reset().

◆ repeated_length

length_model rpnx::compression::xz_codec::lzma_model::repeated_length

Length model for repeated matches.

Definition at line 81 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::decode_lzma_chunk().

◆ state

std::uint8_t rpnx::compression::xz_codec::lzma_model::state = 0U

Current LZMA literal/match state.

Definition at line 67 of file xz.hpp.

Referenced by rpnx::compression::xz_codec::compress_lzma_literals(), rpnx::compression::xz_codec::decode_lzma_chunk(), and reset().

The documentation for this struct was generated from the following file:

include/rpnx/compression/implementation/xz.hpp

RPNX::Compress Self-contained C++20 compression and ZIP library

Classes

Public Member Functions

Public Attributes

Detailed Description

Member Function Documentation

◆ reset()

◆ set_properties()

Member Data Documentation

◆ distance_align

◆ distance_slot

◆ distance_special

◆ is_match

◆ is_rep

◆ is_rep0

◆ is_rep0_long

◆ is_rep1

◆ is_rep2

◆ literal

◆ literal_context_bits

◆ literal_position_bits

◆ match_length

◆ position_bits

◆ rep0

◆ rep1

◆ rep2

◆ rep3

◆ repeated_length

◆ state