1 files changed, 451 insertions, 0 deletions

diff --git a/decoder.h b/decoder.h
new file mode 100644
index 0000000..49e2bef
--- /dev/null
+++ b/decoder.h
@@ -0,0 +1,451 @@
+/*  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; }