diff options
Diffstat (limited to 'lzd.cc')
| -rw-r--r-- | lzd.cc | 114 |
1 files changed, 57 insertions, 57 deletions
@@ -1,5 +1,5 @@ /* Lzd - Educational decompressor for the lzip format - Copyright (C) 2013-2017 Antonio Diaz Diaz. + Copyright (C) 2013-2019 Antonio Diaz Diaz. This program is free software. Redistribution and use in source and binary forms, with or without modification, are permitted provided @@ -29,7 +29,7 @@ #include <cstring> #include <stdint.h> #include <unistd.h> -#if defined(__MSVCRT__) || defined(__OS2__) || defined(_MSC_VER) +#if defined(__MSVCRT__) || defined(__OS2__) || defined(__DJGPP__) #include <fcntl.h> #include <io.h> #endif @@ -130,9 +130,9 @@ public: const CRC32 crc32; -typedef uint8_t File_header[6]; // 0-3 magic, 4 version, 5 coded_dict_size +typedef uint8_t Lzip_header[6]; // 0-3 magic, 4 version, 5 coded_dict_size -typedef uint8_t File_trailer[20]; +typedef uint8_t Lzip_trailer[20]; // 0-3 CRC32 of the uncompressed data // 4-11 size of the uncompressed data // 12-19 member size including header and trailer @@ -326,6 +326,7 @@ bool LZ_decoder::decode_member() // Returns false if error 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]; @@ -334,67 +335,66 @@ bool LZ_decoder::decode_member() // Returns false if error else put_byte( rdec.decode_matched( bm, peek( rep0 ) ) ); state.set_char(); + continue; } - else // match or repeated match + // match or repeated match + int len; + if( rdec.decode_bit( bm_rep[state()] ) != 0 ) // 2nd bit { - 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_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; } - } + 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 { - unsigned distance; - if( rdec.decode_bit( bm_rep1[state()] ) == 0 ) // 4th bit - distance = rep1; + if( rdec.decode_bit( bm_rep2[state()] ) == 0 ) // 5th bit + distance = rep2; else - { - if( rdec.decode_bit( bm_rep2[state()] ) == 0 ) // 5th bit - distance = rep2; - else - { distance = rep3; rep3 = rep2; } - rep2 = rep1; - } - rep1 = rep0; - rep0 = distance; + { distance = rep3; rep3 = rep2; } + rep2 = rep1; } - state.set_rep(); - len = min_match_len + rdec.decode_len( rep_len_model, pos_state ); + rep1 = rep0; + rep0 = distance; } - else // match + state.set_rep(); + len = min_match_len + rdec.decode_len( rep_len_model, pos_state ); + } + else // match + { + rep3 = rep2; rep2 = rep1; rep1 = rep0; + len = min_match_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 ) { - rep3 = rep2; rep2 = rep1; rep1 = rep0; - len = min_match_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 { - 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 { - 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 - } + 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 ) ); + 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; @@ -412,7 +412,7 @@ int main( const int argc, const char * const argv[] ) "It is not safe to use lzd for any real work.\n" "\nUsage: %s < file.lz > file\n", argv[0] ); std::printf( "Lzd decompresses from standard input to standard output.\n" - "\nCopyright (C) 2017 Antonio Diaz Diaz.\n" + "\nCopyright (C) 2019 Antonio Diaz Diaz.\n" "This is free software: you are free to change and redistribute it.\n" "There is NO WARRANTY, to the extent permitted by law.\n" "Report bugs to lzip-bug@nongnu.org\n" @@ -420,14 +420,14 @@ int main( const int argc, const char * const argv[] ) return 0; } -#if defined(__MSVCRT__) || defined(__OS2__) || defined(_MSC_VER) - setmode( fileno( stdin ), O_BINARY ); - setmode( fileno( stdout ), O_BINARY ); +#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 ) { - File_header header; // verify header + Lzip_header header; // verify header for( int i = 0; i < 6; ++i ) header[i] = std::getc( stdin ); if( std::feof( stdin ) || std::memcmp( header, "LZIP\x01", 5 ) != 0 ) { @@ -446,7 +446,7 @@ int main( const int argc, const char * const argv[] ) if( !decoder.decode_member() ) { std::fputs( "Data error\n", stderr ); return 2; } - File_trailer trailer; // verify trailer + Lzip_trailer trailer; // verify trailer for( int i = 0; i < 20; ++i ) trailer[i] = std::getc( stdin ); unsigned crc = 0; for( int i = 3; i >= 0; --i ) { crc <<= 8; crc += trailer[i]; } @@ -457,7 +457,7 @@ int main( const int argc, const char * const argv[] ) } if( std::fclose( stdout ) != 0 ) - { std::fprintf( stderr, "Can't close stdout: %s\n", std::strerror( errno ) ); + { std::fprintf( stderr, "Error closing stdout: %s\n", std::strerror( errno ) ); return 1; } return 0; } |