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+/* 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.
+*/
+
+#ifndef max
+ #define max(x,y) ((x) >= (y) ? (x) : (y))
+#endif
+#ifndef min
+ #define min(x,y) ((x) <= (y) ? (x) : (y))
+#endif
+
+typedef uint8_t State;
+
+enum { states = 12 };
+
+static inline bool St_is_char( const State st ) { return st < 7; }
+
+static inline void St_set_char( State * const st )
+ {
+ static const uint8_t next[states] =
+ { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 };
+ *st = next[*st];
+ }
+
+static inline void St_set_match( State * const st )
+ {
+ static const uint8_t next[states] =
+ { 7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10 };
+ *st = next[*st];
+ }
+
+static inline void St_set_rep( State * const st )
+ {
+ static const uint8_t next[states] =
+ { 8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11 };
+ *st = next[*st];
+ }
+
+static inline void St_set_short_rep( State * const st )
+ {
+ static const uint8_t next[states] =
+ { 9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11 };
+ *st = next[*st];
+ }
+
+
+enum {
+ min_dictionary_bits = 12,
+ min_dictionary_size = 1 << min_dictionary_bits,
+ max_dictionary_bits = 29,
+ max_dictionary_size = 1 << max_dictionary_bits,
+ literal_context_bits = 3,
+ pos_state_bits = 2,
+ pos_states = 1 << pos_state_bits,
+ pos_state_mask = pos_states - 1,
+
+ dis_slot_bits = 6,
+ start_dis_model = 4,
+ end_dis_model = 14,
+ modeled_distances = 1 << (end_dis_model / 2),
+ 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 */
+ max_match_len = min_match_len + max_len_symbols - 1, /* 273 */
+ min_match_len_limit = 5,
+
+ max_dis_states = 4 };
+
+static inline int get_dis_state( int len )
+ {
+ len -= min_match_len;
+ if( len >= max_dis_states ) len = max_dis_states - 1;
+ return len;
+ }
+
+
+enum { bit_model_move_bits = 5,
+ bit_model_total_bits = 11,
+ bit_model_total = 1 << bit_model_total_bits };
+
+typedef unsigned int Bit_model;
+
+static inline void Bm_init( Bit_model * const probability )
+ { *probability = bit_model_total / 2; }
+
+
+static inline int real_bits( const unsigned int value )
+ {
+ int bits = 0, i = 1;
+ unsigned int mask = 1;
+ for( ; mask > 0; ++i, mask <<= 1 ) if( value & mask ) bits = i;
+ return bits;
+ }
+
+
+static const uint8_t magic_string[4] = { 'L', 'Z', 'I', 'P' };
+
+typedef uint8_t File_header[6]; /* 0-3 magic bytes */
+ /* 4 version */
+ /* 5 coded_dict_size */
+enum { Fh_size = 6 };
+
+static inline void Fh_set_magic( File_header data )
+ { memcpy( data, magic_string, 4 ); data[4] = 1; }
+
+static inline bool Fh_verify_magic( const File_header data )
+ { return ( memcmp( data, magic_string, 4 ) == 0 ); }
+
+static inline uint8_t Fh_version( const File_header data )
+ { return data[4]; }
+
+static inline bool Fh_verify_version( const File_header data )
+ { return ( data[4] <= 1 ); }
+
+static inline int Fh_get_dictionary_size( const File_header data )
+ {
+ int sz = ( 1 << ( data[5] & 0x1F ) );
+ if( sz > min_dictionary_size && sz <= max_dictionary_size )
+ sz -= ( sz / 16 ) * ( ( data[5] >> 5 ) & 0x07 );
+ return sz;
+ }
+
+static inline bool Fh_set_dictionary_size( File_header data, const int sz )
+ {
+ if( sz >= min_dictionary_size && sz <= max_dictionary_size )
+ {
+ data[5] = real_bits( sz - 1 );
+ if( sz > min_dictionary_size )
+ {
+ const int base_size = 1 << data[5];
+ const int wedge = base_size / 16;
+ int i;
+ for( i = 7; i >= 1; --i )
+ if( base_size - ( i * wedge ) >= sz )
+ { data[5] |= ( i << 5 ); break; }
+ }
+ return true;
+ }
+ return false;
+ }
+
+static inline bool Fh_verify( const File_header data )
+ {
+ return ( Fh_verify_magic( data ) && Fh_verify_version( data ) &&
+ Fh_get_dictionary_size( data ) >= min_dictionary_size &&
+ Fh_get_dictionary_size( data ) <= max_dictionary_size );
+ }
+
+
+typedef uint8_t File_trailer[20];
+ /* 0-3 CRC32 of the uncompressed data */
+ /* 4-11 size of the uncompressed data */
+ /* 12-19 member size including header and trailer */
+
+enum { Ft_size = 20 };
+
+static inline int Ft_versioned_size( const int version )
+ { return ( ( version >= 1 ) ? 20 : 12 ); }
+
+static inline uint32_t Ft_get_data_crc( const File_trailer data )
+ {
+ uint32_t tmp = 0;
+ int i;
+ for( i = 3; i >= 0; --i ) { tmp <<= 8; tmp += data[i]; }
+ return tmp;
+ }
+
+static inline void Ft_set_data_crc( File_trailer data, uint32_t crc )
+ {
+ int i;
+ for( i = 0; i <= 3; ++i ) { data[i] = (uint8_t)crc; crc >>= 8; }
+ }
+
+static inline long long Ft_get_data_size( const File_trailer data )
+ {
+ long long tmp = 0;
+ int i;
+ for( i = 11; i >= 4; --i ) { tmp <<= 8; tmp += data[i]; }
+ return tmp;
+ }
+
+static inline void Ft_set_data_size( File_trailer data, long long sz )
+ {
+ int i;
+ for( i = 4; i <= 11; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; }
+ }
+
+static inline long long Ft_get_member_size( const File_trailer data )
+ {
+ long long tmp = 0;
+ int i;
+ for( i = 19; i >= 12; --i ) { tmp <<= 8; tmp += data[i]; }
+ return tmp;
+ }
+
+static inline void Ft_set_member_size( File_trailer data, long long sz )
+ {
+ int i;
+ for( i = 12; i <= 19; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; }
+ }