[enhancement ] Reusing the lengths array in ArrowFieldWrites$ArrayWriter's doWrite method

[haohao0103]

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Motivation

ArrowFieldWriters$ArrayWriter#doWrite

Solution

Implementation Steps

1. Reusable Buffer Declaration
   Define a reusable buffer field in ArrayWriter class:

   private int[] reusedLengthsBuffer;  // Reusable array buffer for length storage
   

2. Lazy Initialization & Dynamic Expansion
   In doWrite method, initialize or expand buffer based on runtime lenSize requirements:

   if (reusedLengthsBuffer == null || reusedLengthsBuffer.length < lenSize) {
       int newCapacity = lenSize;
       // Apply 1.5x growth factor if reallocating from existing buffer
       if (reusedLengthsBuffer != null) {
           newCapacity = Math.max(lenSize, (int)(reusedLengthsBuffer.length * 1.5)); 
       }
       reusedLengthsBuffer = new int[newCapacity];  // Allocate or expand buffer
   }
   
   // Reset buffer segment before reuse
   Arrays.fill(reusedLengthsBuffer, 0, lenSize, 0);  
   

Let me know if you have any questions. thanks

Anything else?

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Are you willing to submit a PR?

• [x] I'm willing to submit a PR!