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- namespace SharpCompress.Compressors.LZMA
- {
- internal abstract class Base
- {
- public const uint K_NUM_REP_DISTANCES = 4;
- public const uint K_NUM_STATES = 12;
- // static byte []kLiteralNextStates = {0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5};
- // static byte []kMatchNextStates = {7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10};
- // static byte []kRepNextStates = {8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11};
- // static byte []kShortRepNextStates = {9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11};
- public struct State
- {
- public uint _index;
- public void Init()
- {
- _index = 0;
- }
- public void UpdateChar()
- {
- if (_index < 4)
- {
- _index = 0;
- }
- else if (_index < 10)
- {
- _index -= 3;
- }
- else
- {
- _index -= 6;
- }
- }
- public void UpdateMatch()
- {
- _index = (uint)(_index < 7 ? 7 : 10);
- }
- public void UpdateRep()
- {
- _index = (uint)(_index < 7 ? 8 : 11);
- }
- public void UpdateShortRep()
- {
- _index = (uint)(_index < 7 ? 9 : 11);
- }
- public bool IsCharState()
- {
- return _index < 7;
- }
- }
- public const int K_NUM_POS_SLOT_BITS = 6;
- public const int K_DIC_LOG_SIZE_MIN = 0;
- // public const int kDicLogSizeMax = 30;
- // public const uint kDistTableSizeMax = kDicLogSizeMax * 2;
- public const int K_NUM_LEN_TO_POS_STATES_BITS = 2; // it's for speed optimization
- public const uint K_NUM_LEN_TO_POS_STATES = 1 << K_NUM_LEN_TO_POS_STATES_BITS;
- public const uint K_MATCH_MIN_LEN = 2;
- public static uint GetLenToPosState(uint len)
- {
- len -= K_MATCH_MIN_LEN;
- if (len < K_NUM_LEN_TO_POS_STATES)
- {
- return len;
- }
- return K_NUM_LEN_TO_POS_STATES - 1;
- }
- public const int K_NUM_ALIGN_BITS = 4;
- public const uint K_ALIGN_TABLE_SIZE = 1 << K_NUM_ALIGN_BITS;
- public const uint K_ALIGN_MASK = (K_ALIGN_TABLE_SIZE - 1);
- public const uint K_START_POS_MODEL_INDEX = 4;
- public const uint K_END_POS_MODEL_INDEX = 14;
- public const uint K_NUM_POS_MODELS = K_END_POS_MODEL_INDEX - K_START_POS_MODEL_INDEX;
- public const uint K_NUM_FULL_DISTANCES = 1 << ((int)K_END_POS_MODEL_INDEX / 2);
- public const uint K_NUM_LIT_POS_STATES_BITS_ENCODING_MAX = 4;
- public const uint K_NUM_LIT_CONTEXT_BITS_MAX = 8;
- public const int K_NUM_POS_STATES_BITS_MAX = 4;
- public const uint K_NUM_POS_STATES_MAX = (1 << K_NUM_POS_STATES_BITS_MAX);
- public const int K_NUM_POS_STATES_BITS_ENCODING_MAX = 4;
- public const uint K_NUM_POS_STATES_ENCODING_MAX = (1 << K_NUM_POS_STATES_BITS_ENCODING_MAX);
- public const int K_NUM_LOW_LEN_BITS = 3;
- public const int K_NUM_MID_LEN_BITS = 3;
- public const int K_NUM_HIGH_LEN_BITS = 8;
- public const uint K_NUM_LOW_LEN_SYMBOLS = 1 << K_NUM_LOW_LEN_BITS;
- public const uint K_NUM_MID_LEN_SYMBOLS = 1 << K_NUM_MID_LEN_BITS;
- public const uint K_NUM_LEN_SYMBOLS = K_NUM_LOW_LEN_SYMBOLS + K_NUM_MID_LEN_SYMBOLS +
- (1 << K_NUM_HIGH_LEN_BITS);
- public const uint K_MATCH_MAX_LEN = K_MATCH_MIN_LEN + K_NUM_LEN_SYMBOLS - 1;
- }
- }
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