[jira] [Created] (ARROW-4545) [C#] Extend Append/AppendRange in BinaryArray to support building rows

["Chris Hutchinson (JIRA)" <ji...@apache.org>]

Chris Hutchinson created ARROW-4545:
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             Summary: [C#] Extend Append/AppendRange in BinaryArray to support building rows
                 Key: ARROW-4545
                 URL: https://issues.apache.org/jira/browse/ARROW-4545
             Project: Apache Arrow
          Issue Type: Improvement
          Components: C#
            Reporter: Chris Hutchinson
             Fix For: 0.13.0


This is a proposal to extend BinaryArray to provide the ability to call Append/AppendRange to grow individual rows during array building, and to expose values in ArrowBuffer.Builder<T> through a property to facilitate algorithms that require introspecting the buffer data (sorting, filtering) when building an array.

*Example:*
{code:java}
var builder = new BinaryArray.Builder()
     .Append(10, false)     
     .Append(20, false)
     .Mark();
builder.Append(builder.Values[0], true);
var array = builder.Build();

// General idea:
//
// 1. Append byte (10) to current element (0)
// 2. Append byte (20) to current element (0)
// 3. Mark end of the row 
// 4. Append byte (10) to current element (1)

// Constructs a binary array with 2 elements:
//
// [0] 10, 20
// [1] 10{code}
 

 

This proposed change would add the concept of "current element" to the builder, which in the specification are separated by recording the value offset. Append(true) appends one or more bytes to the current element and then marks the element as completed. Append(false) appends one or more bytes to the current element; Mark is required to signal to the builder that the current element is complete.



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