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Lzw optimizations #59

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Lzw optimizations #59

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Commits on Aug 29, 2024

  1. When reading a tiff file wil lzw compression, the bit size needs to be 

    capped at 12.
    p002308A authored and p002308A committed Aug 29, 2024
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  2. Changed the LZW table to be an array instead of a map for efficiency. 

    The codes are maintained in sequential order starting at zero. It is
inefficient to store them in a map with the keys being Integer objects
when they can be stored in an array and indexed directly. This saves on
map lookups each time and removes the creation of excess Integer objects
when primitives work.

In addition, the values being stored as Integer[] was inefficient when
byte[] is what is needed.

These changes make this section of the code run over twice as fast in
testing.
    p002308A authored and p002308A committed Aug 29, 2024
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  3. Save the old value directly instead of having to relook it up each time.

    p002308A authored and p002308A committed Aug 29, 2024
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  4. Refactored the getNextCode function to be much simpler. 

    This improves the runtime of the entire lzw decompression by about 67%
in testing.
    p002308A authored and p002308A committed Aug 29, 2024
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  5. Simplified the checking of the bit size. 

    Removed the heavy math equation done each time, to a simpler one done
rarely. This give a performance boost to the entire LZW decoding method
of about 50%.
    p002308A authored and p002308A committed Aug 29, 2024
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