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(LzReader): slightly improved LZSS decompression performance.
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199acb763b
commit
0002d55d7d
@ -186,90 +186,52 @@ namespace GameRes.Formats.Kaguya
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internal class LzReader : IDataUnpacker
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{
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Stream m_input;
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byte[] m_output;
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uint m_size;
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MsbBitStream m_input;
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byte[] m_output;
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public byte[] Data { get { return m_output; } }
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public LzReader (Stream input, uint packed_size, uint unpacked_size)
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{
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m_input = input;
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m_input = new MsbBitStream (input, true);
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m_output = new byte[unpacked_size];
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m_size = packed_size;
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m_curbit = 8;
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m_curbyte = 0;
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}
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int m_curbit;
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int m_curbyte;
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public void Unpack ()
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{
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int dst = 0;
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int frame_pos = 1;
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byte[] frame = new byte[4096];
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int frame_mask = frame.Length - 1;
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while (dst < m_output.Length)
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{
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int i;
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if (0 != GetNextBit())
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int bit = m_input.GetNextBit();
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if (-1 == bit)
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break;
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if (0 != bit)
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{
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int data = 0;
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for (i = 0; i < 8; i++)
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{
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int bit = GetNextBit();
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if (-1 == bit)
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return;
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data = (data << 1) | bit;
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}
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int data = m_input.GetBits (8);
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m_output[dst++] = (byte)data;
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frame[frame_pos++] = (byte)data;
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frame_pos &= frame.Length - 1;
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frame_pos &= frame_mask;
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}
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else
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{
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int count, win_offset = 0;
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for (i = 0; i < 12; i++)
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{
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int bit = GetNextBit();
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if (-1 == bit)
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return;
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win_offset = (win_offset << 1) | bit;
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}
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if (0 == win_offset)
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int win_offset = m_input.GetBits (12);
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if (-1 == win_offset || 0 == win_offset)
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break;
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count = 0;
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for (i = 0; i < 4; i++)
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int count = m_input.GetBits(4) + 2;
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for (int i = 0; i < count; i++)
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{
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int bit = GetNextBit();
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if (-1 == bit)
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return;
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count = (count << 1) | bit;
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}
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count += 2;
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for (i = 0; i < count; i++)
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{
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byte data = frame[(win_offset + i) & (frame.Length - 1)];
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byte data = frame[(win_offset + i) & frame_mask];
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m_output[dst++] = data;
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frame[frame_pos++] = data;
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frame_pos &= frame.Length - 1;
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frame_pos &= frame_mask;
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}
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}
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}
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}
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int GetNextBit ()
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{
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if (8 == m_curbit)
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{
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m_curbyte = m_input.ReadByte();
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if (m_curbyte < 0)
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return -1;
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m_curbit = 0;
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}
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return (m_curbyte >> (7 - m_curbit++)) & 1;
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}
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}
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}
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