1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/* Lzlib - Compression library for the lzip format
Copyright (C) 2009-2022 Antonio Diaz Diaz.
This library is free software. Redistribution and use in source and
binary forms, with or without modification, are permitted provided
that the following conditions are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions, and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions, and the following disclaimer in the
documentation and/or other materials provided with the distribution.
This library 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.
*/
static int FLZe_longest_match_len( struct FLZ_encoder * const fe, int * const distance )
{
enum { len_limit = 16 };
int32_t * ptr0 = fe->eb.mb.pos_array + fe->eb.mb.cyclic_pos;
const int available = min( Mb_available_bytes( &fe->eb.mb ), max_match_len );
if( available < len_limit ) { *ptr0 = 0; return 0; }
const uint8_t * const data = Mb_ptr_to_current_pos( &fe->eb.mb );
fe->key4 = ( ( fe->key4 << 4 ) ^ data[3] ) & fe->eb.mb.key4_mask;
const int pos1 = fe->eb.mb.pos + 1;
int newpos1 = fe->eb.mb.prev_positions[fe->key4];
fe->eb.mb.prev_positions[fe->key4] = pos1;
int maxlen = 0, count;
for( count = 4; ; )
{
int delta;
if( newpos1 <= 0 || --count < 0 ||
( delta = pos1 - newpos1 ) > fe->eb.mb.dictionary_size )
{ *ptr0 = 0; break; }
int32_t * const newptr = fe->eb.mb.pos_array +
( fe->eb.mb.cyclic_pos - delta +
( ( fe->eb.mb.cyclic_pos >= delta ) ? 0 : fe->eb.mb.dictionary_size + 1 ) );
if( data[maxlen-delta] == data[maxlen] )
{
int len = 0;
while( len < available && data[len-delta] == data[len] ) ++len;
if( maxlen < len )
{ maxlen = len; *distance = delta - 1;
if( maxlen >= len_limit ) { *ptr0 = *newptr; break; } }
}
*ptr0 = newpos1;
ptr0 = newptr;
newpos1 = *ptr0;
}
return maxlen;
}
static bool FLZe_encode_member( struct FLZ_encoder * const fe )
{
int rep = 0, i;
State * const state = &fe->eb.state;
if( fe->eb.member_finished ) return true;
if( Re_member_position( &fe->eb.renc ) >= fe->eb.member_size_limit )
{ LZeb_try_full_flush( &fe->eb ); return true; }
if( Mb_data_position( &fe->eb.mb ) == 0 &&
!Mb_data_finished( &fe->eb.mb ) ) /* encode first byte */
{
if( !Mb_enough_available_bytes( &fe->eb.mb ) ||
!Re_enough_free_bytes( &fe->eb.renc ) ) return true;
const uint8_t prev_byte = 0;
const uint8_t cur_byte = Mb_peek( &fe->eb.mb, 0 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[*state][0], 0 );
LZeb_encode_literal( &fe->eb, prev_byte, cur_byte );
CRC32_update_byte( &fe->eb.crc, cur_byte );
FLZe_reset_key4( fe );
if( !FLZe_update_and_move( fe, 1 ) ) return false;
}
while( !Mb_data_finished( &fe->eb.mb ) &&
Re_member_position( &fe->eb.renc ) < fe->eb.member_size_limit )
{
if( !Mb_enough_available_bytes( &fe->eb.mb ) ||
!Re_enough_free_bytes( &fe->eb.renc ) ) return true;
int match_distance = 0; /* avoid warning from gcc 6.1.0 */
const int main_len = FLZe_longest_match_len( fe, &match_distance );
const int pos_state = Mb_data_position( &fe->eb.mb ) & pos_state_mask;
int len = 0;
for( i = 0; i < num_rep_distances; ++i )
{
const int tlen = Mb_true_match_len( &fe->eb.mb, 0, fe->eb.reps[i] + 1 );
if( tlen > len ) { len = tlen; rep = i; }
}
if( len > min_match_len && len + 3 > main_len )
{
CRC32_update_buf( &fe->eb.crc, Mb_ptr_to_current_pos( &fe->eb.mb ), len );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[*state][pos_state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[*state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep0[*state], rep != 0 );
if( rep == 0 )
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_len[*state][pos_state], 1 );
else
{
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep1[*state], rep > 1 );
if( rep > 1 )
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep2[*state], rep > 2 );
const int distance = fe->eb.reps[rep];
for( i = rep; i > 0; --i ) fe->eb.reps[i] = fe->eb.reps[i-1];
fe->eb.reps[0] = distance;
}
*state = St_set_rep( *state );
Re_encode_len( &fe->eb.renc, &fe->eb.rep_len_model, len, pos_state );
if( !Mb_move_pos( &fe->eb.mb ) ) return false;
if( !FLZe_update_and_move( fe, len - 1 ) ) return false;
continue;
}
if( main_len > min_match_len )
{
CRC32_update_buf( &fe->eb.crc, Mb_ptr_to_current_pos( &fe->eb.mb ), main_len );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[*state][pos_state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[*state], 0 );
*state = St_set_match( *state );
for( i = num_rep_distances - 1; i > 0; --i ) fe->eb.reps[i] = fe->eb.reps[i-1];
fe->eb.reps[0] = match_distance;
LZeb_encode_pair( &fe->eb, match_distance, main_len, pos_state );
if( !Mb_move_pos( &fe->eb.mb ) ) return false;
if( !FLZe_update_and_move( fe, main_len - 1 ) ) return false;
continue;
}
const uint8_t prev_byte = Mb_peek( &fe->eb.mb, 1 );
const uint8_t cur_byte = Mb_peek( &fe->eb.mb, 0 );
const uint8_t match_byte = Mb_peek( &fe->eb.mb, fe->eb.reps[0] + 1 );
if( !Mb_move_pos( &fe->eb.mb ) ) return false;
CRC32_update_byte( &fe->eb.crc, cur_byte );
if( match_byte == cur_byte )
{
const int short_rep_price = price1( fe->eb.bm_match[*state][pos_state] ) +
price1( fe->eb.bm_rep[*state] ) +
price0( fe->eb.bm_rep0[*state] ) +
price0( fe->eb.bm_len[*state][pos_state] );
int price = price0( fe->eb.bm_match[*state][pos_state] );
if( St_is_char( *state ) )
price += LZeb_price_literal( &fe->eb, prev_byte, cur_byte );
else
price += LZeb_price_matched( &fe->eb, prev_byte, cur_byte, match_byte );
if( short_rep_price < price )
{
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[*state][pos_state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[*state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep0[*state], 0 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_len[*state][pos_state], 0 );
*state = St_set_short_rep( *state );
continue;
}
}
/* literal byte */
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[*state][pos_state], 0 );
if( ( *state = St_set_char( *state ) ) < 4 )
LZeb_encode_literal( &fe->eb, prev_byte, cur_byte );
else
LZeb_encode_matched( &fe->eb, prev_byte, cur_byte, match_byte );
}
LZeb_try_full_flush( &fe->eb );
return true;
}
|
