lzip/encoder_base.h

483 lines
14 KiB
C++

/* Lzip - LZMA lossless data compressor
Copyright (C) 2008-2024 Antonio Diaz Diaz.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
enum { price_shift_bits = 6,
price_step_bits = 2,
price_step = 1 << price_step_bits };
class Dis_slots
{
uint8_t data[1<<10];
public:
void init()
{
for( int slot = 0; slot < 4; ++slot ) data[slot] = slot;
for( int i = 4, size = 2, slot = 4; slot < 20; slot += 2 )
{
std::memset( &data[i], slot, size );
std::memset( &data[i+size], slot + 1, size );
size <<= 1;
i += size;
}
}
uint8_t operator[]( const int dis ) const { return data[dis]; }
};
extern Dis_slots dis_slots;
inline uint8_t get_slot( const unsigned dis )
{
if( dis < (1 << 10) ) return dis_slots[dis];
if( dis < (1 << 19) ) return dis_slots[dis>> 9] + 18;
if( dis < (1 << 28) ) return dis_slots[dis>>18] + 36;
return dis_slots[dis>>27] + 54;
}
class Prob_prices
{
short data[bit_model_total >> price_step_bits];
public:
void init()
{
for( int i = 0; i < bit_model_total >> price_step_bits; ++i )
{
unsigned val = ( i * price_step ) + ( price_step / 2 );
int bits = 0; // base 2 logarithm of val
for( int j = 0; j < price_shift_bits; ++j )
{
val = val * val;
bits <<= 1;
while( val >= 1 << 16 ) { val >>= 1; ++bits; }
}
bits += 15; // remaining bits in val
data[i] = ( bit_model_total_bits << price_shift_bits ) - bits;
}
}
int operator[]( const int probability ) const
{ return data[probability >> price_step_bits]; }
};
extern Prob_prices prob_prices;
inline int price0( const Bit_model bm )
{ return prob_prices[bm.probability]; }
inline int price1( const Bit_model bm )
{ return prob_prices[bit_model_total - bm.probability]; }
inline int price_bit( const Bit_model bm, const bool bit )
{ return bit ? price1( bm ) : price0( bm ); }
inline int price_symbol3( const Bit_model bm[], int symbol )
{
bool bit = symbol & 1;
symbol |= 8; symbol >>= 1;
int price = price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
return price + price_bit( bm[1], symbol & 1 );
}
inline int price_symbol6( const Bit_model bm[], unsigned symbol )
{
bool bit = symbol & 1;
symbol |= 64; symbol >>= 1;
int price = price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
return price + price_bit( bm[1], symbol & 1 );
}
inline int price_symbol8( const Bit_model bm[], int symbol )
{
bool bit = symbol & 1;
symbol |= 0x100; symbol >>= 1;
int price = price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
bit = symbol & 1; symbol >>= 1; price += price_bit( bm[symbol], bit );
return price + price_bit( bm[1], symbol & 1 );
}
inline int price_symbol_reversed( const Bit_model bm[], int symbol,
const int num_bits )
{
int price = 0;
int model = 1;
for( int i = num_bits; i > 0; --i )
{
const bool bit = symbol & 1;
symbol >>= 1;
price += price_bit( bm[model], bit );
model <<= 1; model |= bit;
}
return price;
}
inline int price_matched( const Bit_model bm[], unsigned symbol,
unsigned match_byte )
{
int price = 0;
unsigned mask = 0x100;
symbol |= mask;
while( true )
{
const unsigned match_bit = ( match_byte <<= 1 ) & mask;
const bool bit = ( symbol <<= 1 ) & 0x100;
price += price_bit( bm[(symbol>>9)+match_bit+mask], bit );
if( symbol >= 0x10000 ) return price;
mask &= ~(match_bit ^ symbol); // if( match_bit != bit ) mask = 0;
}
}
class Matchfinder_base
{
bool read_block();
void normalize_pos();
Matchfinder_base( const Matchfinder_base & ); // declared as private
void operator=( const Matchfinder_base & ); // declared as private
protected:
unsigned long long partial_data_pos;
uint8_t * buffer; // input buffer
int32_t * prev_positions; // 1 + last seen position of key. else 0
int32_t * pos_array; // may be tree or chain
const int before_size; // bytes to keep in buffer before dictionary
int buffer_size;
int dictionary_size; // bytes to keep in buffer before pos
int pos; // current pos in buffer
int cyclic_pos; // cycles through [0, dictionary_size]
int stream_pos; // first byte not yet read from file
int pos_limit; // when reached, a new block must be read
int key4_mask;
const int num_prev_positions23;
int num_prev_positions; // size of prev_positions
int pos_array_size;
const int infd; // input file descriptor
bool at_stream_end; // stream_pos shows real end of file
Matchfinder_base( const int before_size_,
const int dict_size, const int after_size,
const int dict_factor, const int num_prev_positions23_,
const int pos_array_factor, const int ifd );
~Matchfinder_base()
{ delete[] prev_positions; std::free( buffer ); }
public:
uint8_t peek( const int distance ) const { return buffer[pos-distance]; }
int available_bytes() const { return stream_pos - pos; }
unsigned long long data_position() const { return partial_data_pos + pos; }
bool data_finished() const { return at_stream_end && pos >= stream_pos; }
const uint8_t * ptr_to_current_pos() const { return buffer + pos; }
int true_match_len( const int index, const int distance ) const
{
const uint8_t * const data = buffer + pos;
int i = index;
const int len_limit = std::min( available_bytes(), (int)max_match_len );
while( i < len_limit && data[i-distance] == data[i] ) ++i;
return i;
}
void move_pos()
{
if( ++cyclic_pos > dictionary_size ) cyclic_pos = 0;
if( ++pos >= pos_limit ) normalize_pos();
}
void reset();
};
class Range_encoder
{
enum { buffer_size = 65536 };
uint64_t low;
unsigned long long partial_member_pos;
uint8_t * const buffer; // output buffer
int pos; // current pos in buffer
uint32_t range;
unsigned ff_count;
const int outfd; // output file descriptor
uint8_t cache;
Lzip_header header;
void shift_low()
{
if( low >> 24 != 0xFF )
{
const bool carry = ( low > 0xFFFFFFFFU );
put_byte( cache + carry );
for( ; ff_count > 0; --ff_count ) put_byte( 0xFF + carry );
cache = low >> 24;
}
else ++ff_count;
low = ( low & 0x00FFFFFFU ) << 8;
}
Range_encoder( const Range_encoder & ); // declared as private
void operator=( const Range_encoder & ); // declared as private
public:
void reset( const unsigned dictionary_size )
{
low = 0;
partial_member_pos = 0;
pos = 0;
range = 0xFFFFFFFFU;
ff_count = 0;
cache = 0;
header.dictionary_size( dictionary_size );
for( int i = 0; i < header.size; ++i ) put_byte( header.data[i] );
}
Range_encoder( const unsigned dictionary_size, const int ofd )
:
buffer( new uint8_t[buffer_size] ), outfd( ofd )
{
header.set_magic();
reset( dictionary_size );
}
~Range_encoder() { delete[] buffer; }
unsigned long long member_position() const
{ return partial_member_pos + pos + ff_count; }
void flush() { for( int i = 0; i < 5; ++i ) shift_low(); }
void flush_data();
void put_byte( const uint8_t b )
{
buffer[pos] = b;
if( ++pos >= buffer_size ) flush_data();
}
void encode( const int symbol, const int num_bits )
{
for( unsigned mask = 1 << ( num_bits - 1 ); mask > 0; mask >>= 1 )
{
range >>= 1;
if( symbol & mask ) low += range;
if( range <= 0x00FFFFFFU ) { range <<= 8; shift_low(); }
}
}
void encode_bit( Bit_model & bm, const bool bit )
{
const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability;
if( !bit )
{
range = bound;
bm.probability +=
( bit_model_total - bm.probability ) >> bit_model_move_bits;
}
else
{
low += bound;
range -= bound;
bm.probability -= bm.probability >> bit_model_move_bits;
}
if( range <= 0x00FFFFFFU ) { range <<= 8; shift_low(); }
}
void encode_tree3( Bit_model bm[], const int symbol )
{
bool bit = ( symbol >> 2 ) & 1;
encode_bit( bm[1], bit );
int model = 2 | bit;
bit = ( symbol >> 1 ) & 1;
encode_bit( bm[model], bit ); model <<= 1; model |= bit;
encode_bit( bm[model], symbol & 1 );
}
void encode_tree6( Bit_model bm[], const unsigned symbol )
{
bool bit = ( symbol >> 5 ) & 1;
encode_bit( bm[1], bit );
int model = 2 | bit;
bit = ( symbol >> 4 ) & 1;
encode_bit( bm[model], bit ); model <<= 1; model |= bit;
bit = ( symbol >> 3 ) & 1;
encode_bit( bm[model], bit ); model <<= 1; model |= bit;
bit = ( symbol >> 2 ) & 1;
encode_bit( bm[model], bit ); model <<= 1; model |= bit;
bit = ( symbol >> 1 ) & 1;
encode_bit( bm[model], bit ); model <<= 1; model |= bit;
encode_bit( bm[model], symbol & 1 );
}
void encode_tree8( Bit_model bm[], const int symbol )
{
int model = 1;
for( int i = 7; i >= 0; --i )
{
const bool bit = ( symbol >> i ) & 1;
encode_bit( bm[model], bit );
model <<= 1; model |= bit;
}
}
void encode_tree_reversed( Bit_model bm[], int symbol, const int num_bits )
{
int model = 1;
for( int i = num_bits; i > 0; --i )
{
const bool bit = symbol & 1;
symbol >>= 1;
encode_bit( bm[model], bit );
model <<= 1; model |= bit;
}
}
void encode_matched( Bit_model bm[], unsigned symbol, unsigned match_byte )
{
unsigned mask = 0x100;
symbol |= mask;
while( true )
{
const unsigned match_bit = ( match_byte <<= 1 ) & mask;
const bool bit = ( symbol <<= 1 ) & 0x100;
encode_bit( bm[(symbol>>9)+match_bit+mask], bit );
if( symbol >= 0x10000 ) break;
mask &= ~(match_bit ^ symbol); // if( match_bit != bit ) mask = 0;
}
}
void encode_len( Len_model & lm, int symbol, const int pos_state )
{
bool bit = ( ( symbol -= min_match_len ) >= len_low_symbols );
encode_bit( lm.choice1, bit );
if( !bit )
encode_tree3( lm.bm_low[pos_state], symbol );
else
{
bit = ( ( symbol -= len_low_symbols ) >= len_mid_symbols );
encode_bit( lm.choice2, bit );
if( !bit )
encode_tree3( lm.bm_mid[pos_state], symbol );
else
encode_tree8( lm.bm_high, symbol - len_mid_symbols );
}
}
};
class LZ_encoder_base : public Matchfinder_base
{
protected:
enum { max_marker_size = 16,
num_rep_distances = 4 }; // must be 4
uint32_t crc_;
Bit_model bm_literal[1<<literal_context_bits][0x300];
Bit_model bm_match[State::states][pos_states];
Bit_model bm_rep[State::states];
Bit_model bm_rep0[State::states];
Bit_model bm_rep1[State::states];
Bit_model bm_rep2[State::states];
Bit_model bm_len[State::states][pos_states];
Bit_model bm_dis_slot[len_states][1<<dis_slot_bits];
Bit_model bm_dis[modeled_distances-end_dis_model+1];
Bit_model bm_align[dis_align_size];
Len_model match_len_model;
Len_model rep_len_model;
Range_encoder renc;
LZ_encoder_base( const int before_size, const int dict_size,
const int after_size, const int dict_factor,
const int num_prev_positions23,
const int pos_array_factor,
const int ifd, const int outfd )
:
Matchfinder_base( before_size, dict_size, after_size, dict_factor,
num_prev_positions23, pos_array_factor, ifd ),
crc_( 0xFFFFFFFFU ),
renc( dictionary_size, outfd )
{}
unsigned crc() const { return crc_ ^ 0xFFFFFFFFU; }
int price_literal( const uint8_t prev_byte, const uint8_t symbol ) const
{ return price_symbol8( bm_literal[get_lit_state(prev_byte)], symbol ); }
int price_matched( const uint8_t prev_byte, const uint8_t symbol,
const uint8_t match_byte ) const
{ return ::price_matched( bm_literal[get_lit_state(prev_byte)], symbol,
match_byte ); }
void encode_literal( const uint8_t prev_byte, const uint8_t symbol )
{ renc.encode_tree8( bm_literal[get_lit_state(prev_byte)], symbol ); }
void encode_matched( const uint8_t prev_byte, const uint8_t symbol,
const uint8_t match_byte )
{ renc.encode_matched( bm_literal[get_lit_state(prev_byte)], symbol,
match_byte ); }
void encode_pair( const unsigned dis, const int len, const int pos_state )
{
renc.encode_len( match_len_model, len, pos_state );
const unsigned dis_slot = get_slot( dis );
renc.encode_tree6( bm_dis_slot[get_len_state(len)], dis_slot );
if( dis_slot >= start_dis_model )
{
const int direct_bits = ( dis_slot >> 1 ) - 1;
const unsigned base = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
const unsigned direct_dis = dis - base;
if( dis_slot < end_dis_model )
renc.encode_tree_reversed( bm_dis + ( base - dis_slot ),
direct_dis, direct_bits );
else
{
renc.encode( direct_dis >> dis_align_bits, direct_bits - dis_align_bits );
renc.encode_tree_reversed( bm_align, direct_dis, dis_align_bits );
}
}
}
void full_flush( const State state );
public:
virtual ~LZ_encoder_base() {}
unsigned long long member_position() const { return renc.member_position(); }
virtual void reset();
virtual bool encode_member( const unsigned long long member_size ) = 0;
};