Adding upstream version 1.4.upstream/1.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 488 insertions, 0 deletions

diff --git a/lzd.cc b/lzd.cc
new file mode 100644
index 0000000..3cf3f13
--- /dev/null
+++ b/lzd.cc
@@ -0,0 +1,488 @@
+/* Lzd - Educational decompressor for the lzip format
+   Copyright (C) 2013-2024 Antonio Diaz Diaz.
+
+   This program 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 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.
+*/
+/*
+   Exit status: 0 for a normal exit, 1 for environmental problems
+   (file not found, invalid command-line options, I/O errors, etc), 2 to
+   indicate a corrupt or invalid input file.
+*/
+
+#include <algorithm>
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <stdint.h>
+#include <unistd.h>
+#if defined __MSVCRT__ || defined __OS2__ || defined __DJGPP__
+#include <fcntl.h>
+#include <io.h>
+#endif
+
+
+class State
+  {
+  int st;
+
+public:
+  enum { states = 12 };
+  State() : st( 0 ) {}
+  int operator()() const { return st; }
+  bool is_char() const { return st < 7; }
+
+  void set_char()
+    {
+    const int next[states] = { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 };
+    st = next[st];
+    }
+  void set_match()     { st = ( st < 7 ) ? 7 : 10; }
+  void set_rep()       { st = ( st < 7 ) ? 8 : 11; }
+  void set_short_rep() { st = ( st < 7 ) ? 9 : 11; }
+  };
+
+
+enum {
+  min_dictionary_size = 1 << 12,
+  max_dictionary_size = 1 << 29,
+  literal_context_bits = 3,
+  literal_pos_state_bits = 0,				// not used
+  pos_state_bits = 2,
+  pos_states = 1 << pos_state_bits,
+  pos_state_mask = pos_states - 1,
+
+  len_states = 4,
+  dis_slot_bits = 6,
+  start_dis_model = 4,
+  end_dis_model = 14,
+  modeled_distances = 1 << ( end_dis_model / 2 ),	// 128
+  dis_align_bits = 4,
+  dis_align_size = 1 << dis_align_bits,
+
+  len_low_bits = 3,
+  len_mid_bits = 3,
+  len_high_bits = 8,
+  len_low_symbols = 1 << len_low_bits,
+  len_mid_symbols = 1 << len_mid_bits,
+  len_high_symbols = 1 << len_high_bits,
+  max_len_symbols = len_low_symbols + len_mid_symbols + len_high_symbols,
+
+  min_match_len = 2,					// must be 2
+
+  bit_model_move_bits = 5,
+  bit_model_total_bits = 11,
+  bit_model_total = 1 << bit_model_total_bits };
+
+struct Bit_model
+  {
+  int probability;
+  Bit_model() : probability( bit_model_total / 2 ) {}
+  };
+
+struct Len_model
+  {
+  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];
+  };
+
+
+class CRC32
+  {
+  uint32_t data[256];		// Table of CRCs of all 8-bit messages.
+
+public:
+  CRC32()
+    {
+    for( unsigned n = 0; n < 256; ++n )
+      {
+      unsigned c = n;
+      for( int k = 0; k < 8; ++k )
+        { if( c & 1 ) c = 0xEDB88320U ^ ( c >> 1 ); else c >>= 1; }
+      data[n] = c;
+      }
+    }
+
+  void update_buf( uint32_t & crc, const uint8_t * const buffer,
+                   const int size ) const
+    {
+    for( int i = 0; i < size; ++i )
+      crc = data[(crc^buffer[i])&0xFF] ^ ( crc >> 8 );
+    }
+  };
+
+const CRC32 crc32;
+
+
+enum { header_size = 6, trailer_size = 20 };
+typedef uint8_t Lzip_header[header_size]; // 0-3 magic bytes
+					  //   4 version
+					  //   5 coded dictionary size
+typedef uint8_t Lzip_trailer[trailer_size];
+			//  0-3  CRC32 of the uncompressed data
+			//  4-11 size of the uncompressed data
+			// 12-19 member size including header and trailer
+
+class Range_decoder
+  {
+  unsigned long long member_pos;
+  uint32_t code;
+  uint32_t range;
+
+public:
+  Range_decoder()
+    : member_pos( header_size ), code( 0 ), range( 0xFFFFFFFFU )
+    {
+    get_byte();			// discard first byte of the LZMA stream
+    for( int i = 0; i < 4; ++i ) code = ( code << 8 ) | get_byte();
+    }
+
+  uint8_t get_byte() { ++member_pos; return std::getc( stdin ); }
+  unsigned long long member_position() const { return member_pos; }
+
+  unsigned decode( const int num_bits )
+    {
+    unsigned symbol = 0;
+    for( int i = num_bits; i > 0; --i )
+      {
+      range >>= 1;
+      symbol <<= 1;
+      if( code >= range ) { code -= range; symbol |= 1; }
+      if( range <= 0x00FFFFFFU )			// normalize
+        { range <<= 8; code = ( code << 8 ) | get_byte(); }
+      }
+    return symbol;
+    }
+
+  bool decode_bit( Bit_model & bm )
+    {
+    bool symbol;
+    const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability;
+    if( code < bound )
+      {
+      range = bound;
+      bm.probability +=
+        ( bit_model_total - bm.probability ) >> bit_model_move_bits;
+      symbol = 0;
+      }
+    else
+      {
+      code -= bound;
+      range -= bound;
+      bm.probability -= bm.probability >> bit_model_move_bits;
+      symbol = 1;
+      }
+    if( range <= 0x00FFFFFFU )				// normalize
+      { range <<= 8; code = ( code << 8 ) | get_byte(); }
+    return symbol;
+    }
+
+  unsigned decode_tree( Bit_model bm[], const int num_bits )
+    {
+    unsigned symbol = 1;
+    for( int i = 0; i < num_bits; ++i )
+      symbol = ( symbol << 1 ) | decode_bit( bm[symbol] );
+    return symbol - ( 1 << num_bits );
+    }
+
+  unsigned decode_tree_reversed( Bit_model bm[], const int num_bits )
+    {
+    unsigned symbol = decode_tree( bm, num_bits );
+    unsigned reversed_symbol = 0;
+    for( int i = 0; i < num_bits; ++i )
+      {
+      reversed_symbol = ( reversed_symbol << 1 ) | ( symbol & 1 );
+      symbol >>= 1;
+      }
+    return reversed_symbol;
+    }
+
+  unsigned decode_matched( Bit_model bm[], const unsigned match_byte )
+    {
+    unsigned symbol = 1;
+    for( int i = 7; i >= 0; --i )
+      {
+      const bool match_bit = ( match_byte >> i ) & 1;
+      const bool bit = decode_bit( bm[symbol+(match_bit<<8)+0x100] );
+      symbol = ( symbol << 1 ) | bit;
+      if( match_bit != bit )
+        {
+        while( symbol < 0x100 )
+          symbol = ( symbol << 1 ) | decode_bit( bm[symbol] );
+        break;
+        }
+      }
+    return symbol & 0xFF;
+    }
+
+  unsigned decode_len( Len_model & lm, const int pos_state )
+    {
+    if( decode_bit( lm.choice1 ) == 0 )
+      return min_match_len +
+             decode_tree( lm.bm_low[pos_state], len_low_bits );
+    if( decode_bit( lm.choice2 ) == 0 )
+      return min_match_len + len_low_symbols +
+             decode_tree( lm.bm_mid[pos_state], len_mid_bits );
+    return min_match_len + len_low_symbols + len_mid_symbols +
+           decode_tree( lm.bm_high, len_high_bits );
+    }
+  };
+
+
+class LZ_decoder
+  {
+  unsigned long long partial_data_pos;
+  Range_decoder rdec;
+  const unsigned dictionary_size;
+  uint8_t * const buffer;	// output buffer
+  unsigned pos;			// current pos in buffer
+  unsigned stream_pos;		// first byte not yet written to stdout
+  uint32_t crc_;
+  bool pos_wrapped;
+
+  void flush_data();
+
+  uint8_t peek( const unsigned distance ) const
+    {
+    if( pos > distance ) return buffer[pos - distance - 1];
+    if( pos_wrapped ) return buffer[dictionary_size + pos - distance - 1];
+    return 0;			// prev_byte of first byte
+    }
+
+  void put_byte( const uint8_t b )
+    {
+    buffer[pos] = b;
+    if( ++pos >= dictionary_size ) flush_data();
+    }
+
+public:
+  explicit LZ_decoder( const unsigned dict_size )
+    :
+    partial_data_pos( 0 ),
+    dictionary_size( dict_size ),
+    buffer( new uint8_t[dictionary_size] ),
+    pos( 0 ),
+    stream_pos( 0 ),
+    crc_( 0xFFFFFFFFU ),
+    pos_wrapped( false )
+    {}
+
+  ~LZ_decoder() { delete[] buffer; }
+
+  unsigned crc() const { return crc_ ^ 0xFFFFFFFFU; }
+  unsigned long long data_position() const
+    { return partial_data_pos + pos; }
+  uint8_t get_byte() { return rdec.get_byte(); }
+  unsigned long long member_position() const
+    { return rdec.member_position(); }
+
+  bool decode_member();
+  };
+
+
+void LZ_decoder::flush_data()
+  {
+  if( pos > stream_pos )
+    {
+    const unsigned size = pos - stream_pos;
+    crc32.update_buf( crc_, buffer + stream_pos, size );
+    if( std::fwrite( buffer + stream_pos, 1, size, stdout ) != size )
+      { std::fprintf( stderr, "Write error: %s\n", std::strerror( errno ) );
+        std::exit( 1 ); }
+    if( pos >= dictionary_size )
+      { partial_data_pos += pos; pos = 0; pos_wrapped = true; }
+    stream_pos = pos;
+    }
+  }
+
+
+bool LZ_decoder::decode_member()	// Return false if error
+  {
+  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;
+  unsigned rep0 = 0;		// rep[0-3] latest four distances
+  unsigned rep1 = 0;		// used for efficient coding of
+  unsigned rep2 = 0;		// repeated distances
+  unsigned rep3 = 0;
+  State state;
+
+  while( !std::feof( stdin ) && !std::ferror( stdin ) )
+    {
+    const int pos_state = data_position() & pos_state_mask;
+    if( rdec.decode_bit( bm_match[state()][pos_state] ) == 0 )	// 1st bit
+      {
+      // literal byte
+      const uint8_t prev_byte = peek( 0 );
+      const int literal_state = prev_byte >> ( 8 - literal_context_bits );
+      Bit_model * const bm = bm_literal[literal_state];
+      if( state.is_char() )
+        put_byte( rdec.decode_tree( bm, 8 ) );
+      else
+        put_byte( rdec.decode_matched( bm, peek( rep0 ) ) );
+      state.set_char();
+      continue;
+      }
+    // match or repeated match
+    int len;
+    if( rdec.decode_bit( bm_rep[state()] ) != 0 )		// 2nd bit
+      {
+      if( rdec.decode_bit( bm_rep0[state()] ) == 0 )		// 3rd bit
+        {
+        if( rdec.decode_bit( bm_len[state()][pos_state] ) == 0 ) // 4th bit
+          { state.set_short_rep(); put_byte( peek( rep0 ) ); continue; }
+        }
+      else
+        {
+        unsigned distance;
+        if( rdec.decode_bit( bm_rep1[state()] ) == 0 )		// 4th bit
+          distance = rep1;
+        else
+          {
+          if( rdec.decode_bit( bm_rep2[state()] ) == 0 )	// 5th bit
+            distance = rep2;
+          else
+            { distance = rep3; rep3 = rep2; }
+          rep2 = rep1;
+          }
+        rep1 = rep0;
+        rep0 = distance;
+        }
+      state.set_rep();
+      len = rdec.decode_len( rep_len_model, pos_state );
+      }
+    else					// match
+      {
+      rep3 = rep2; rep2 = rep1; rep1 = rep0;
+      len = rdec.decode_len( match_len_model, pos_state );
+      const int len_state = std::min( len - min_match_len, len_states - 1 );
+      rep0 = rdec.decode_tree( bm_dis_slot[len_state], dis_slot_bits );
+      if( rep0 >= start_dis_model )
+        {
+        const unsigned dis_slot = rep0;
+        const int direct_bits = ( dis_slot >> 1 ) - 1;
+        rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
+        if( dis_slot < end_dis_model )
+          rep0 += rdec.decode_tree_reversed( bm_dis + ( rep0 - dis_slot ),
+                                             direct_bits );
+        else
+          {
+          rep0 +=
+            rdec.decode( direct_bits - dis_align_bits ) << dis_align_bits;
+          rep0 += rdec.decode_tree_reversed( bm_align, dis_align_bits );
+          if( rep0 == 0xFFFFFFFFU )		// marker found
+            {
+            flush_data();
+            return len == min_match_len;	// End Of Stream marker
+            }
+          }
+        }
+      state.set_match();
+      if( rep0 >= dictionary_size || ( rep0 >= pos && !pos_wrapped ) )
+        { flush_data(); return false; }
+      }
+    for( int i = 0; i < len; ++i ) put_byte( peek( rep0 ) );
+    }
+  flush_data();
+  return false;
+  }
+
+
+int main( const int argc, const char * const argv[] )
+  {
+  if( argc > 2 || ( argc == 2 && std::strcmp( argv[1], "-d" ) != 0 ) )
+    {
+    std::printf(
+      "Lzd %s - Educational decompressor for the lzip format.\n"
+      "Study the source code to learn how a lzip decompressor works.\n"
+      "See the lzip manual for an explanation of the code.\n"
+      "\nUsage: %s [-d] < file.lz > file\n"
+      "Lzd decompresses from standard input to standard output.\n"
+      "\nCopyright (C) 2024 Antonio Diaz Diaz.\n"
+      "License 2-clause BSD.\n"
+      "This is free software: you are free to change and redistribute "
+      "it.\nThere is NO WARRANTY, to the extent permitted by law.\n"
+      "Report bugs to lzip-bug@nongnu.org\n"
+      "Lzd home page: http://www.nongnu.org/lzip/lzd.html\n",
+      PROGVERSION, argv[0] );
+    return 0;
+    }
+
+#if defined __MSVCRT__ || defined __OS2__ || defined __DJGPP__
+  setmode( STDIN_FILENO, O_BINARY );
+  setmode( STDOUT_FILENO, O_BINARY );
+#endif
+
+  for( bool first_member = true; ; first_member = false )
+    {
+    Lzip_header header;				// check header
+    for( int i = 0; i < header_size; ++i ) header[i] = std::getc( stdin );
+    if( std::feof( stdin ) || std::memcmp( header, "LZIP\x01", 5 ) != 0 )
+      {
+      if( first_member )
+        { std::fputs( "Bad magic number (file not in lzip format).\n",
+                      stderr ); return 2; }
+      break;					// ignore trailing data
+      }
+    unsigned dict_size = 1 << ( header[5] & 0x1F );
+    dict_size -= ( dict_size / 16 ) * ( ( header[5] >> 5 ) & 7 );
+    if( dict_size < min_dictionary_size || dict_size > max_dictionary_size )
+      { std::fputs( "Invalid dictionary size in member header.\n",
+                    stderr ); return 2; }
+
+    LZ_decoder decoder( dict_size );		// decode LZMA stream
+    if( !decoder.decode_member() )
+      { std::fputs( "Data error\n", stderr ); return 2; }
+
+    Lzip_trailer trailer;			// check trailer
+    for( int i = 0; i < trailer_size; ++i ) trailer[i] = decoder.get_byte();
+    int retval = 0;
+    unsigned crc = 0;
+    for( int i = 3; i >= 0; --i ) crc = ( crc << 8 ) + trailer[i];
+    if( crc != decoder.crc() )
+      { std::fputs( "CRC mismatch\n", stderr ); retval = 2; }
+
+    unsigned long long data_size = 0;
+    for( int i = 11; i >= 4; --i )
+      data_size = ( data_size << 8 ) + trailer[i];
+    if( data_size != decoder.data_position() )
+      { std::fputs( "Data size mismatch\n", stderr ); retval = 2; }
+
+    unsigned long long member_size = 0;
+    for( int i = 19; i >= 12; --i )
+      member_size = ( member_size << 8 ) + trailer[i];
+    if( member_size != decoder.member_position() )
+      { std::fputs( "Member size mismatch\n", stderr ); retval = 2; }
+    if( retval ) return retval;
+    }
+
+  if( std::fclose( stdout ) != 0 )
+    { std::fprintf( stderr, "Error closing stdout: %s\n",
+                    std::strerror( errno ) ); return 1; }
+  return 0;
+  }