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   1 #ifndef _WIMLIB_LZMS_H
   2 #define _WIMLIB_LZMS_H
   3
   4 /* Constants for the LZMS data compression format.  See the comments in
   5  * lzms-decompress.c for more information about this format.  */
   6
   7 //#define ENABLE_LZMS_DEBUG
   8 #ifdef ENABLE_LZMS_DEBUG
   9 #       define LZMS_DEBUG DEBUG
  10 #       define LZMS_ASSERT wimlib_assert
  11 #else
  12 #       define LZMS_DEBUG(format, ...)
  13 #       define LZMS_ASSERT(...)
  14 #endif
  15
  16 #define LZMS_NUM_RECENT_OFFSETS                 3
  17
  18 #define LZMS_PROBABILITY_BITS                   6
  19 #define LZMS_PROBABILITY_MAX                    (1U << LZMS_PROBABILITY_BITS)
  20 #define LZMS_INITIAL_PROBABILITY                48
  21 #define LZMS_INITIAL_RECENT_BITS                0x0000000055555555ULL
  22
  23 #define LZMS_NUM_MAIN_STATES                    16
  24 #define LZMS_NUM_MATCH_STATES                   32
  25 #define LZMS_NUM_LZ_MATCH_STATES                64
  26 #define LZMS_NUM_LZ_REPEAT_MATCH_STATES         64
  27 #define LZMS_NUM_DELTA_MATCH_STATES             64
  28 #define LZMS_NUM_DELTA_REPEAT_MATCH_STATES      64
  29 #define LZMS_MAX_NUM_STATES                     64
  30
  31 #define LZMS_NUM_LITERAL_SYMS                   256
  32 #define LZMS_NUM_LEN_SYMS                       54
  33 #define LZMS_NUM_DELTA_POWER_SYMS               8
  34 #define LZMS_MAX_NUM_OFFSET_SYMS                799
  35 #define LZMS_MAX_NUM_SYMS                       799
  36
  37 #define LZMS_MAX_CODEWORD_LEN                   15
  38
  39 #define LZMS_LITERAL_CODE_REBUILD_FREQ          1024
  40 #define LZMS_LZ_OFFSET_CODE_REBUILD_FREQ        1024
  41 #define LZMS_LENGTH_CODE_REBUILD_FREQ           512
  42 #define LZMS_DELTA_OFFSET_CODE_REBUILD_FREQ     1024
  43 #define LZMS_DELTA_POWER_CODE_REBUILD_FREQ      512
  44
  45 #define LZMS_X86_MAX_GOOD_TARGET_OFFSET         65535
  46 #define LZMS_X86_MAX_TRANSLATION_OFFSET         1023
  47
  48 /* Code shared between the LZMS decompressor and compressor.  */
  49
  50 #include <wimlib/types.h>
  51
  52 extern void
  53 lzms_x86_filter(u8 data[], s32 size, s32 last_target_usages[], bool undo);
  54
  55 /* Probability entry for use by the range coder when in a specific state.  */
  56 struct lzms_probability_entry {
  57
  58         /* Number of zeroes in the most recent LZMS_PROBABILITY_MAX bits that
  59          * have been coded using this probability entry.  This is a cached value
  60          * because it can be computed as LZMS_PROBABILITY_MAX minus the Hamming
  61          * weight of the low-order LZMS_PROBABILITY_MAX bits of @recent_bits.
  62          * */
  63         u32 num_recent_zero_bits;
  64
  65         /* The most recent LZMS_PROBABILITY_MAX bits that have been coded using
  66          * this probability entry.  The size of this variable, in bits, must be
  67          * at least LZMS_PROBABILITY_MAX.  */
  68         u64 recent_bits;
  69 };
  70
  71 extern u32 lzms_position_slot_base[LZMS_MAX_NUM_OFFSET_SYMS + 1];
  72
  73 extern u32 lzms_length_slot_base[LZMS_NUM_LEN_SYMS + 1];
  74
  75 extern void
  76 lzms_init_slot_bases(void);
  77
  78 extern u32
  79 lzms_get_slot(u32 value, const u32 slot_base_tab[], unsigned num_slots);
  80
  81 static inline u32
  82 lzms_get_position_slot(u32 value)
  83 {
  84         return lzms_get_slot(value, lzms_position_slot_base,
  85                              LZMS_MAX_NUM_OFFSET_SYMS);
  86 }
  87
  88 static inline u32
  89 lzms_get_length_slot(u32 value)
  90 {
  91         return lzms_get_slot(value, lzms_length_slot_base,
  92                              LZMS_NUM_LEN_SYMS);
  93 }
  94
  95 #endif /* _WIMLIB_LZMS_H  */