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-rw-r--r--decoder.h451
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+/* Lzlib - A compression library for lzip files
+ Copyright (C) 2009, 2010, 2011, 2012, 2013 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.
+*/
+
+enum { rd_min_available_bytes = 8 };
+
+struct Range_decoder
+ {
+ struct Circular_buffer cb; /* input buffer */
+ unsigned 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 bool Rd_finished( const struct Range_decoder * const rdec )
+ { return rdec->at_stream_end && !Cb_used_bytes( &rdec->cb ); }
+
+static inline void Rd_finish( struct Range_decoder * const rdec )
+ { rdec->at_stream_end = true; }
+
+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_available_bytes( const struct Range_decoder * const rdec )
+ { return 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 get = rdec->cb.get;
+ int i;
+ File_header header;
+ for( i = 0; i < Fh_size; ++i )
+ {
+ if( get == rdec->cb.put ) return false; /* not enough data */
+ header[i] = rdec->cb.buffer[get];
+ if( ++get >= rdec->cb.buffer_size ) get = 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 get = rdec->cb.get;
+ int i;
+ for( i = 0; i < Fh_size; ++i )
+ {
+ if( get == rdec->cb.put ) return false; /* not enough data */
+ header[i] = rdec->cb.buffer[get];
+ if( ++get >= rdec->cb.buffer_size ) get = 0;
+ }
+ if( Fh_verify( header ) )
+ {
+ rdec->cb.get = get;
+ 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 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;
+ }
+
+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;
+ for( i = 0; i < 5; ++i )
+ rdec->code = (rdec->code << 8) | Rd_get_byte( rdec );
+ rdec->range = 0xFFFFFFFFU;
+ }
+ return !rdec->reload_pending;
+ }
+
+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( struct Range_decoder * const rdec,
+ const int num_bits )
+ {
+ int symbol = 0;
+ int i;
+ for( i = num_bits; i > 0; --i )
+ {
+ uint32_t mask;
+ Rd_normalize( rdec );
+ rdec->range >>= 1;
+/* symbol <<= 1; */
+/* if( rdec->code >= rdec->range ) { rdec->code -= rdec->range; symbol |= 1; } */
+ mask = 0U - (rdec->code < rdec->range);
+ rdec->code -= rdec->range;
+ rdec->code += rdec->range & mask;
+ symbol = (symbol << 1) + (mask + 1);
+ }
+ return symbol;
+ }
+
+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_tree6( struct Range_decoder * const rdec,
+ Bit_model bm[] )
+ {
+ int model = 1;
+ model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) | Rd_decode_bit( rdec, &bm[model] );
+ return model - (1 << 6);
+ }
+
+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 bool bit = Rd_decode_bit( rdec, &bm[model] );
+ model <<= 1;
+ if( bit ) { ++model; symbol |= (1 << i); }
+ }
+ return symbol;
+ }
+
+static inline int Rd_decode_tree_reversed4( struct Range_decoder * const rdec,
+ Bit_model bm[] )
+ {
+ int model = 1;
+ int symbol = 0;
+ int bit = Rd_decode_bit( rdec, &bm[model] );
+ model = (model << 1) + bit; symbol |= bit;
+ bit = Rd_decode_bit( rdec, &bm[model] );
+ model = (model << 1) + bit; symbol |= (bit << 1);
+ bit = Rd_decode_bit( rdec, &bm[model] );
+ model = (model << 1) + bit; symbol |= (bit << 2);
+ if( Rd_decode_bit( rdec, &bm[model] ) ) symbol |= 8;
+ return symbol;
+ }
+
+static inline int Rd_decode_matched( struct Range_decoder * const rdec,
+ Bit_model bm[], int match_byte )
+ {
+ Bit_model * const bm1 = bm + 0x100;
+ int symbol = 1;
+ int i;
+ for( i = 7; i >= 0; --i )
+ {
+ int match_bit, bit;
+ match_byte <<= 1;
+ match_bit = match_byte & 0x100;
+ bit = Rd_decode_bit( rdec, &bm1[match_bit+symbol] );
+ symbol = ( symbol << 1 ) | bit;
+ if( match_bit != bit << 8 )
+ {
+ while( symbol < 0x100 )
+ symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
+ break;
+ }
+ }
+ return symbol - 0x100;
+ }
+
+
+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 )
+ {
+ Bm_init( &len_decoder->choice1 );
+ Bm_init( &len_decoder->choice2 );
+ Bm_array_init( len_decoder->bm_low[0], pos_states * len_low_symbols );
+ Bm_array_init( len_decoder->bm_mid[0], pos_states * len_mid_symbols );
+ Bm_array_init( len_decoder->bm_high, len_high_symbols );
+ }
+
+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 );
+ }
+
+
+enum { lzd_min_free_bytes = max_match_len };
+
+struct LZ_decoder
+ {
+ struct Circular_buffer cb;
+ unsigned long long partial_data_pos;
+ int dictionary_size;
+ uint32_t crc;
+ int member_version;
+ bool member_finished;
+ bool verify_trailer_pending;
+ unsigned rep0; /* rep[0-3] latest four distances */
+ unsigned rep1; /* used for efficient coding of */
+ unsigned rep2; /* repeated distances */
+ unsigned rep3;
+ State state;
+
+ Bit_model bm_literal[1<<literal_context_bits][0x300];
+ 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];
+ Bit_model bm_align[dis_align_size];
+
+ struct Range_decoder * range_decoder;
+ struct Len_decoder len_decoder;
+ struct Len_decoder rep_match_len_decoder;
+ };
+
+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_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 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 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; }
+ }
+
+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 ) ) /* no wrap, no overlap */
+ {
+ 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 )
+ {
+ LZd_put_byte( decoder, decoder->cb.buffer[i] );
+ if( ++i >= decoder->cb.buffer_size ) i = 0;
+ }
+ }
+
+static inline bool LZd_init( struct LZ_decoder * const decoder,
+ const File_header header,
+ struct Range_decoder * const rdec )
+ {
+ decoder->dictionary_size = Fh_get_dictionary_size( header );
+ if( !Cb_init( &decoder->cb, max( 65536, decoder->dictionary_size ) + lzd_min_free_bytes ) )
+ return false;
+ decoder->partial_data_pos = 0;
+ 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;
+
+ Bm_array_init( decoder->bm_literal[0], (1 << literal_context_bits) * 0x300 );
+ Bm_array_init( decoder->bm_match[0], states * pos_states );
+ Bm_array_init( decoder->bm_rep, states );
+ Bm_array_init( decoder->bm_rep0, states );
+ Bm_array_init( decoder->bm_rep1, states );
+ Bm_array_init( decoder->bm_rep2, states );
+ Bm_array_init( decoder->bm_len[0], states * pos_states );
+ Bm_array_init( decoder->bm_dis_slot[0], max_dis_states * (1 << dis_slot_bits) );
+ Bm_array_init( decoder->bm_dis, modeled_distances - end_dis_model );
+ Bm_array_init( decoder->bm_align, dis_align_size );
+
+ decoder->range_decoder = rdec;
+ Led_init( &decoder->len_decoder );
+ Led_init( &decoder->rep_match_len_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 unsigned LZd_crc( const struct LZ_decoder * const decoder )
+ { return decoder->crc ^ 0xFFFFFFFFU; }
+
+static inline unsigned long long
+LZd_data_position( const struct LZ_decoder * const decoder )
+ { return decoder->partial_data_pos + decoder->cb.put; }