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author | Daniel Baumann <mail@daniel-baumann.ch> | 2015-11-07 13:45:54 +0000 |
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committer | Daniel Baumann <mail@daniel-baumann.ch> | 2015-11-07 13:45:54 +0000 |
commit | 53eee7f4e2ef4d4211df3e860e3c787fbd83c3e8 (patch) | |
tree | cff02b70b5a48f7cefa4a5ad4c4ab745e2b64dd6 /decoder.c | |
parent | Adding upstream version 1.2. (diff) | |
download | lzlib-53eee7f4e2ef4d4211df3e860e3c787fbd83c3e8.tar.xz lzlib-53eee7f4e2ef4d4211df3e860e3c787fbd83c3e8.zip |
Adding upstream version 1.3.upstream/1.3
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to 'decoder.c')
-rw-r--r-- | decoder.c | 734 |
1 files changed, 734 insertions, 0 deletions
diff --git a/decoder.c b/decoder.c new file mode 100644 index 0000000..d3ea0d6 --- /dev/null +++ b/decoder.c @@ -0,0 +1,734 @@ +/* Lzlib - A compression library for lzip files + Copyright (C) 2009, 2010, 2011, 2012 Antonio Diaz Diaz. + + This library 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 3 of the License, or + (at your option) any later version. + + 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. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this library. If not, see <http://www.gnu.org/licenses/>. + + As a special exception, you may use this file as part of a free + software library without restriction. Specifically, if other files + instantiate templates or use macros or inline functions from this + file, or you compile this file and link it with other files to + produce an executable, this file does not by itself cause the + resulting executable to be covered by the GNU General Public + License. This exception does not however invalidate any other + reasons why the executable file might be covered by the GNU General + Public License. +*/ + +struct Circular_buffer + { + uint8_t * buffer; + int buffer_size; /* capacity == buffer_size - 1 */ + int get; /* buffer is empty when get == put */ + int put; + }; + +static inline void Cb_reset( struct Circular_buffer * const cb ) + { cb->get = 0; cb->put = 0; } + +static inline bool Cb_init( struct Circular_buffer * const cb, + const int buf_size ) + { + cb->buffer = (uint8_t *)malloc( buf_size + 1 ); + cb->buffer_size = buf_size + 1; + cb->get = 0; + cb->put = 0; + return ( cb->buffer != 0 ); + } + +static inline void Cb_free( struct Circular_buffer * const cb ) + { free( cb->buffer ); cb->buffer = 0; } + +static inline int Cb_used_bytes( const struct Circular_buffer * const cb ) + { return ( (cb->get <= cb->put) ? 0 : cb->buffer_size ) + cb->put - cb->get; } + +static inline int Cb_free_bytes( const struct Circular_buffer * const cb ) + { return ( (cb->get <= cb->put) ? cb->buffer_size : 0 ) - cb->put + cb->get - 1; } + +static inline uint8_t Cb_get_byte( struct Circular_buffer * const cb ) + { + const uint8_t b = cb->buffer[cb->get]; + if( ++cb->get >= cb->buffer_size ) cb->get = 0; + return b; + } + +static inline void Cb_put_byte( struct Circular_buffer * const cb, + const uint8_t b ) + { + cb->buffer[cb->put] = b; + if( ++cb->put >= cb->buffer_size ) cb->put = 0; + } + + +/* Copies up to 'out_size' bytes to 'out_buffer' and updates 'get'. + Returns the number of bytes copied. +*/ +static int Cb_read_data( struct Circular_buffer * const cb, + uint8_t * const out_buffer, const int out_size ) + { + if( out_size < 0 ) return 0; + int size = 0; + if( cb->get > cb->put ) + { + size = min( cb->buffer_size - cb->get, out_size ); + if( size > 0 ) + { + memcpy( out_buffer, cb->buffer + cb->get, size ); + cb->get += size; + if( cb->get >= cb->buffer_size ) cb->get = 0; + } + } + if( cb->get < cb->put ) + { + const int size2 = min( cb->put - cb->get, out_size - size ); + if( size2 > 0 ) + { + memcpy( out_buffer + size, cb->buffer + cb->get, size2 ); + cb->get += size2; + size += size2; + } + } + return size; + } + + +/* Copies up to 'in_size' bytes from 'in_buffer' and updates 'put'. + Returns the number of bytes copied. +*/ +static int Cb_write_data( struct Circular_buffer * const cb, + const uint8_t * const in_buffer, const int in_size ) + { + if( in_size < 0 ) return 0; + int size = 0; + if( cb->put >= cb->get ) + { + size = min( cb->buffer_size - cb->put - (cb->get == 0), in_size ); + if( size > 0 ) + { + memcpy( cb->buffer + cb->put, in_buffer, size ); + cb->put += size; + if( cb->put >= cb->buffer_size ) cb->put = 0; + } + } + if( cb->put < cb->get ) + { + const int size2 = min( cb->get - cb->put - 1, in_size - size ); + if( size2 > 0 ) + { + memcpy( cb->buffer + cb->put, in_buffer + size, size2 ); + cb->put += size2; + size += size2; + } + } + return size; + } + + +enum { rd_min_available_bytes = 8 }; + +struct Range_decoder + { + struct Circular_buffer cb; + long long member_position; + uint32_t code; + uint32_t range; + bool reload_pending; + bool at_stream_end; + }; + +static inline bool Rd_init( struct Range_decoder * const rdec ) + { + if( !Cb_init( &rdec->cb, 65536 + rd_min_available_bytes ) ) return false; + rdec->member_position = 0; + rdec->code = 0; + rdec->range = 0xFFFFFFFFU; + rdec->reload_pending = false; + rdec->at_stream_end = false; + return true; + } + +static inline void Rd_free( struct Range_decoder * const rdec ) + { Cb_free( &rdec->cb ); } + +static inline int Rd_available_bytes( const struct Range_decoder * const rdec ) + { return Cb_used_bytes( &rdec->cb ); } + +static inline void Rd_finish( struct Range_decoder * const rdec ) + { rdec->at_stream_end = true; } + +static inline bool Rd_finished( const struct Range_decoder * const rdec ) + { return rdec->at_stream_end && !Cb_used_bytes( &rdec->cb ); } + +static inline int Rd_free_bytes( const struct Range_decoder * const rdec ) + { if( rdec->at_stream_end ) return 0; return Cb_free_bytes( &rdec->cb ); } + +static inline void Rd_purge( struct Range_decoder * const rdec ) + { rdec->at_stream_end = true; Cb_reset( &rdec->cb ); } + +static inline void Rd_reset( struct Range_decoder * const rdec ) + { rdec->at_stream_end = false; Cb_reset( &rdec->cb ); } + + +/* Seeks a member header and updates 'get'. + Returns true if it finds a valid header. +*/ +static bool Rd_find_header( struct Range_decoder * const rdec ) + { + while( rdec->cb.get != rdec->cb.put ) + { + if( rdec->cb.buffer[rdec->cb.get] == magic_string[0] ) + { + int g = rdec->cb.get; + int i; + File_header header; + for( i = 0; i < Fh_size; ++i ) + { + if( g == rdec->cb.put ) return false; /* not enough data */ + header[i] = rdec->cb.buffer[g]; + if( ++g >= rdec->cb.buffer_size ) g = 0; + } + if( Fh_verify( header ) ) return true; + } + if( ++rdec->cb.get >= rdec->cb.buffer_size ) rdec->cb.get = 0; + } + return false; + } + + +/* Returns true, fills 'header', and updates 'get' if 'get' points to a + valid header. + Else returns false and leaves 'get' unmodified. +*/ +static bool Rd_read_header( struct Range_decoder * const rdec, + File_header header ) + { + int g = rdec->cb.get; + int i; + for( i = 0; i < Fh_size; ++i ) + { + if( g == rdec->cb.put ) return false; /* not enough data */ + header[i] = rdec->cb.buffer[g]; + if( ++g >= rdec->cb.buffer_size ) g = 0; + } + if( Fh_verify( header ) ) + { + rdec->cb.get = g; + rdec->member_position = Fh_size; + rdec->reload_pending = true; + return true; + } + return false; + } + + +static inline int Rd_write_data( struct Range_decoder * const rdec, + const uint8_t * const inbuf, const int size ) + { + if( rdec->at_stream_end || size <= 0 ) return 0; + return Cb_write_data( &rdec->cb, inbuf, size ); + } + +static inline uint8_t Rd_get_byte( struct Range_decoder * const rdec ) + { + ++rdec->member_position; + return Cb_get_byte( &rdec->cb ); + } + + +static bool Rd_try_reload( struct Range_decoder * const rdec, const bool force ) + { + if( force ) rdec->reload_pending = true; + if( rdec->reload_pending && Rd_available_bytes( rdec ) >= 5 ) + { + int i; + rdec->reload_pending = false; + rdec->code = 0; + rdec->range = 0xFFFFFFFFU; + for( i = 0; i < 5; ++i ) + rdec->code = (rdec->code << 8) | Rd_get_byte( rdec ); + } + return !rdec->reload_pending; + } + + +static inline int Rd_decode( struct Range_decoder * const rdec, + const int num_bits ) + { + int symbol = 0; + int i; + for( i = num_bits; i > 0; --i ) + { + symbol <<= 1; + if( rdec->range <= 0x00FFFFFFU ) + { + rdec->range <<= 7; + rdec->code = (rdec->code << 8) | Rd_get_byte( rdec ); + if( rdec->code >= rdec->range ) + { rdec->code -= rdec->range; symbol |= 1; } + } + else + { + rdec->range >>= 1; + if( rdec->code >= rdec->range ) + { rdec->code -= rdec->range; symbol |= 1; } + } + } + return symbol; + } + + +static inline void Rd_normalize( struct Range_decoder * const rdec ) + { + if( rdec->range <= 0x00FFFFFFU ) + { + rdec->range <<= 8; + rdec->code = (rdec->code << 8) | Rd_get_byte( rdec ); + } + } + + +static inline int Rd_decode_bit( struct Range_decoder * const rdec, + Bit_model * const probability ) + { + uint32_t bound; + Rd_normalize( rdec ); + bound = ( rdec->range >> bit_model_total_bits ) * *probability; + if( rdec->code < bound ) + { + rdec->range = bound; + *probability += (bit_model_total - *probability) >> bit_model_move_bits; + return 0; + } + else + { + rdec->range -= bound; + rdec->code -= bound; + *probability -= *probability >> bit_model_move_bits; + return 1; + } + } + + +static inline int Rd_decode_tree( struct Range_decoder * const rdec, + Bit_model bm[], const int num_bits ) + { + int model = 1; + int i; + for( i = num_bits; i > 0; --i ) + model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] ); + return model - (1 << num_bits); + } + + +static inline int Rd_decode_matched( struct Range_decoder * const rdec, + Bit_model bm[], const int match_byte ) + { + Bit_model * const bm1 = bm + 0x100; + int symbol = 1; + int i; + for( i = 7; i >= 0; --i ) + { + const int match_bit = ( match_byte >> i ) & 1; + const int bit = Rd_decode_bit( rdec, &bm1[(match_bit<<8)+symbol] ); + symbol = ( symbol << 1 ) | bit; + if( match_bit != bit ) + { + while( --i >= 0 ) + symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] ); + break; + } + } + return symbol & 0xFF; + } + + +static inline int Rd_decode_tree_reversed( struct Range_decoder * const rdec, + Bit_model bm[], const int num_bits ) + { + int model = 1; + int symbol = 0; + int i; + for( i = 0; i < num_bits; ++i ) + { + const int bit = Rd_decode_bit( rdec, &bm[model] ); + model <<= 1; + if( bit ) { model |= 1; symbol |= (1 << i); } + } + return symbol; + } + + +static inline bool Rd_enough_available_bytes( const struct Range_decoder * const rdec ) + { + return ( Cb_used_bytes( &rdec->cb ) >= rd_min_available_bytes || + ( rdec->at_stream_end && Cb_used_bytes( &rdec->cb ) > 0 ) ); + } + + +static inline int Rd_read_data( struct Range_decoder * const rdec, + uint8_t * const outbuf, const int size ) + { + const int sz = Cb_read_data( &rdec->cb, outbuf, size ); + if( sz > 0 ) rdec->member_position += sz; + return sz; + } + + +struct Len_decoder + { + Bit_model choice1; + Bit_model choice2; + Bit_model bm_low[pos_states][len_low_symbols]; + Bit_model bm_mid[pos_states][len_mid_symbols]; + Bit_model bm_high[len_high_symbols]; + }; + +static inline void Led_init( struct Len_decoder * const len_decoder ) + { + int i, j; + Bm_init( &len_decoder->choice1 ); + Bm_init( &len_decoder->choice2 ); + for( i = 0; i < pos_states; ++i ) + for( j = 0; j < len_low_symbols; ++j ) + Bm_init( &len_decoder->bm_low[i][j] ); + for( i = 0; i < pos_states; ++i ) + for( j = 0; j < len_mid_symbols; ++j ) + Bm_init( &len_decoder->bm_mid[i][j] ); + for( i = 0; i < len_high_symbols; ++i ) + Bm_init( &len_decoder->bm_high[i] ); + } + +static inline int Led_decode( struct Len_decoder * const len_decoder, + struct Range_decoder * const rdec, + const int pos_state ) + { + if( Rd_decode_bit( rdec, &len_decoder->choice1 ) == 0 ) + return Rd_decode_tree( rdec, len_decoder->bm_low[pos_state], len_low_bits ); + if( Rd_decode_bit( rdec, &len_decoder->choice2 ) == 0 ) + return len_low_symbols + + Rd_decode_tree( rdec, len_decoder->bm_mid[pos_state], len_mid_bits ); + return len_low_symbols + len_mid_symbols + + Rd_decode_tree( rdec, len_decoder->bm_high, len_high_bits ); + } + + +struct Literal_decoder + { + Bit_model bm_literal[1<<literal_context_bits][0x300]; + }; + +static inline void Lid_init( struct Literal_decoder * const lidec ) + { + int i, j; + for( i = 0; i < 1<<literal_context_bits; ++i ) + for( j = 0; j < 0x300; ++j ) + Bm_init( &lidec->bm_literal[i][j] ); + } + +static inline int Lid_state( const uint8_t prev_byte ) + { return ( prev_byte >> ( 8 - literal_context_bits ) ); } + +static inline uint8_t Lid_decode( struct Literal_decoder * const lidec, + struct Range_decoder * const rdec, + const uint8_t prev_byte ) + { return Rd_decode_tree( rdec, lidec->bm_literal[Lid_state(prev_byte)], 8 ); } + +static inline uint8_t Lid_decode_matched( struct Literal_decoder * const lidec, + struct Range_decoder * const rdec, + const uint8_t prev_byte, + const uint8_t match_byte ) + { return Rd_decode_matched( rdec, lidec->bm_literal[Lid_state(prev_byte)], match_byte ); } + + +enum { lzd_min_free_bytes = max_match_len }; + +struct LZ_decoder + { + struct Circular_buffer cb; + long long partial_data_pos; + int dictionary_size; + uint32_t crc; + int member_version; + bool member_finished; + bool verify_trailer_pending; + unsigned int rep0; /* rep[0-3] latest four distances */ + unsigned int rep1; /* used for efficient coding of */ + unsigned int rep2; /* repeated distances */ + unsigned int rep3; + State state; + + Bit_model bm_match[states][pos_states]; + Bit_model bm_rep[states]; + Bit_model bm_rep0[states]; + Bit_model bm_rep1[states]; + Bit_model bm_rep2[states]; + Bit_model bm_len[states][pos_states]; + Bit_model bm_dis_slot[max_dis_states][1<<dis_slot_bits]; + Bit_model bm_dis[modeled_distances-end_dis_model+1]; + Bit_model bm_align[dis_align_size]; + + struct Range_decoder * range_decoder; + struct Len_decoder len_decoder; + struct Len_decoder rep_match_len_decoder; + struct Literal_decoder literal_decoder; + }; + +static inline bool LZd_init( struct LZ_decoder * const decoder, + const File_header header, + struct Range_decoder * const rdec ) + { + int i, j; + if( !Cb_init( &decoder->cb, max( 65536, Fh_get_dictionary_size( header ) ) + lzd_min_free_bytes ) ) + return false; + decoder->partial_data_pos = 0; + decoder->dictionary_size = Fh_get_dictionary_size( header ); + decoder->crc = 0xFFFFFFFFU; + decoder->member_version = Fh_version( header ); + decoder->member_finished = false; + decoder->verify_trailer_pending = false; + decoder->rep0 = 0; + decoder->rep1 = 0; + decoder->rep2 = 0; + decoder->rep3 = 0; + decoder->state = 0; + + for( i = 0; i < states; ++i ) + { + for( j = 0; j < pos_states; ++j ) + { + Bm_init( &decoder->bm_match[i][j] ); + Bm_init( &decoder->bm_len[i][j] ); + } + Bm_init( &decoder->bm_rep[i] ); + Bm_init( &decoder->bm_rep0[i] ); + Bm_init( &decoder->bm_rep1[i] ); + Bm_init( &decoder->bm_rep2[i] ); + } + for( i = 0; i < max_dis_states; ++i ) + for( j = 0; j < 1<<dis_slot_bits; ++j ) + Bm_init( &decoder->bm_dis_slot[i][j] ); + for( i = 0; i < modeled_distances-end_dis_model+1; ++i ) + Bm_init( &decoder->bm_dis[i] ); + for( i = 0; i < dis_align_size; ++i ) + Bm_init( &decoder->bm_align[i] ); + + decoder->range_decoder = rdec; + Led_init( &decoder->len_decoder ); + Led_init( &decoder->rep_match_len_decoder ); + Lid_init( &decoder->literal_decoder ); + decoder->cb.buffer[decoder->cb.buffer_size-1] = 0; /* prev_byte of first_byte */ + return true; + } + +static inline void LZd_free( struct LZ_decoder * const decoder ) + { Cb_free( &decoder->cb ); } + +static inline bool LZd_member_finished( const struct LZ_decoder * const decoder ) + { return ( decoder->member_finished && !Cb_used_bytes( &decoder->cb ) ); } + +static inline uint32_t LZd_crc( const struct LZ_decoder * const decoder ) + { return decoder->crc ^ 0xFFFFFFFFU; } + +static inline long long LZd_data_position( const struct LZ_decoder * const decoder ) + { return decoder->partial_data_pos + decoder->cb.put; } + + +static bool LZd_verify_trailer( struct LZ_decoder * const decoder ) + { + File_trailer trailer; + const int trailer_size = Ft_versioned_size( decoder->member_version ); + const long long member_size = + decoder->range_decoder->member_position + trailer_size; + + int size = Rd_read_data( decoder->range_decoder, trailer, trailer_size ); + if( size < trailer_size ) return false; + + if( decoder->member_version == 0 ) Ft_set_member_size( trailer, member_size ); + + if( decoder->range_decoder->code != 0 || + Ft_get_data_crc( trailer ) != LZd_crc( decoder ) || + Ft_get_data_size( trailer ) != LZd_data_position( decoder ) || + Ft_get_member_size( trailer ) != member_size ) return false; + return true; + } + + +static inline void LZd_copy_block( struct LZ_decoder * const decoder, + const int distance, int len ) + { + int i = decoder->cb.put - distance - 1; + if( i < 0 ) i += decoder->cb.buffer_size; + if( len < decoder->cb.buffer_size - max( decoder->cb.put, i ) && + len <= abs( decoder->cb.put - i ) ) + { + CRC32_update_buf( &decoder->crc, decoder->cb.buffer + i, len ); + memcpy( decoder->cb.buffer + decoder->cb.put, decoder->cb.buffer + i, len ); + decoder->cb.put += len; + } + else for( ; len > 0; --len ) + { + CRC32_update_byte( &decoder->crc, decoder->cb.buffer[i] ); + decoder->cb.buffer[decoder->cb.put] = decoder->cb.buffer[i]; + if( ++decoder->cb.put >= decoder->cb.buffer_size ) + { decoder->partial_data_pos += decoder->cb.put; decoder->cb.put = 0; } + if( ++i >= decoder->cb.buffer_size ) i = 0; + } + } + + +static inline bool LZd_enough_free_bytes( const struct LZ_decoder * const decoder ) + { return Cb_free_bytes( &decoder->cb ) >= lzd_min_free_bytes; } + + +static inline uint8_t LZd_get_byte( const struct LZ_decoder * const decoder, + const int distance ) + { + int i = decoder->cb.put - distance - 1; + if( i < 0 ) i += decoder->cb.buffer_size; + return decoder->cb.buffer[i]; + } + +static inline uint8_t LZd_get_prev_byte( const struct LZ_decoder * const decoder ) + { + const int i = + ( ( decoder->cb.put > 0 ) ? decoder->cb.put : decoder->cb.buffer_size ) - 1; + return decoder->cb.buffer[i]; + } + +static inline void LZd_put_byte( struct LZ_decoder * const decoder, + const uint8_t b ) + { + CRC32_update_byte( &decoder->crc, b ); + decoder->cb.buffer[decoder->cb.put] = b; + if( ++decoder->cb.put >= decoder->cb.buffer_size ) + { decoder->partial_data_pos += decoder->cb.put; decoder->cb.put = 0; } + } + + +/* Return value: 0 = OK, 1 = decoder error, 2 = unexpected EOF, + 3 = trailer error, 4 = unknown marker found. */ +static int LZd_decode_member( struct LZ_decoder * const decoder ) + { + State * const state = &decoder->state; + if( decoder->member_finished ) return 0; + if( !Rd_try_reload( decoder->range_decoder, false ) ) return 0; + if( decoder->verify_trailer_pending ) + { + if( Rd_available_bytes( decoder->range_decoder ) < Ft_versioned_size( decoder->member_version ) && + !decoder->range_decoder->at_stream_end ) + return 0; + decoder->verify_trailer_pending = false; + decoder->member_finished = true; + if( LZd_verify_trailer( decoder ) ) return 0; else return 3; + } + + while( !Rd_finished( decoder->range_decoder ) ) + { + const int pos_state = LZd_data_position( decoder ) & pos_state_mask; + if( !Rd_enough_available_bytes( decoder->range_decoder ) || + !LZd_enough_free_bytes( decoder ) ) + return 0; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_match[*state][pos_state] ) == 0 ) + { + const uint8_t prev_byte = LZd_get_prev_byte( decoder ); + if( St_is_char( *state ) ) + LZd_put_byte( decoder, Lid_decode( &decoder->literal_decoder, + decoder->range_decoder, prev_byte ) ); + else + LZd_put_byte( decoder, Lid_decode_matched( &decoder->literal_decoder, + decoder->range_decoder, prev_byte, LZd_get_byte( decoder, decoder->rep0 ) ) ); + St_set_char( state ); + } + else + { + int len; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep[*state] ) == 1 ) + { + len = 0; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep0[*state] ) == 1 ) + { + unsigned int distance; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep1[*state] ) == 0 ) + distance = decoder->rep1; + else + { + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep2[*state] ) == 0 ) + distance = decoder->rep2; + else { distance = decoder->rep3; decoder->rep3 = decoder->rep2; } + decoder->rep2 = decoder->rep1; + } + decoder->rep1 = decoder->rep0; + decoder->rep0 = distance; + } + else + { + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_len[*state][pos_state] ) == 0 ) + { St_set_short_rep( state ); len = 1; } + } + if( len == 0 ) + { + St_set_rep( state ); + len = min_match_len + Led_decode( &decoder->rep_match_len_decoder, decoder->range_decoder, pos_state ); + } + } + else + { + int dis_slot; + const unsigned int rep0_saved = decoder->rep0; + len = min_match_len + Led_decode( &decoder->len_decoder, decoder->range_decoder, pos_state ); + dis_slot = Rd_decode_tree( decoder->range_decoder, decoder->bm_dis_slot[get_dis_state(len)], dis_slot_bits ); + if( dis_slot < start_dis_model ) decoder->rep0 = dis_slot; + else + { + const int direct_bits = ( dis_slot >> 1 ) - 1; + decoder->rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits; + if( dis_slot < end_dis_model ) + decoder->rep0 += Rd_decode_tree_reversed( decoder->range_decoder, decoder->bm_dis + decoder->rep0 - dis_slot, direct_bits ); + else + { + decoder->rep0 += Rd_decode( decoder->range_decoder, direct_bits - dis_align_bits ) << dis_align_bits; + decoder->rep0 += Rd_decode_tree_reversed( decoder->range_decoder, decoder->bm_align, dis_align_bits ); + if( decoder->rep0 == 0xFFFFFFFFU ) /* Marker found */ + { + decoder->rep0 = rep0_saved; + Rd_normalize( decoder->range_decoder ); + if( len == min_match_len ) /* End Of Stream marker */ + { + if( Rd_available_bytes( decoder->range_decoder ) < Ft_versioned_size( decoder->member_version ) && + !decoder->range_decoder->at_stream_end ) + { decoder->verify_trailer_pending = true; return 0; } + decoder->member_finished = true; + if( LZd_verify_trailer( decoder ) ) return 0; else return 3; + } + if( len == min_match_len + 1 ) /* Sync Flush marker */ + { + if( Rd_try_reload( decoder->range_decoder, true ) ) continue; + else return 0; + } + return 4; + } + } + } + decoder->rep3 = decoder->rep2; + decoder->rep2 = decoder->rep1; decoder->rep1 = rep0_saved; + St_set_match( state ); + if( decoder->rep0 >= (unsigned int)decoder->dictionary_size || + ( decoder->rep0 >= (unsigned int)decoder->cb.put && + !decoder->partial_data_pos ) ) + return 1; + } + LZd_copy_block( decoder, decoder->rep0, len ); + } + } + return 2; + } |