[SNAP-860] Removed hardcoding of size of Array used for storing DecimalType (#38)

Created a jira for -Pspark precheckin SNAP-914 (https://jira.snappydata.io/browse/SNAP-914)

Author: SachinJanani

sql/catalyst/src/main/scala/org/apache/spark/sql/types/DecimalType.scala

@@ -31,7 +31,7 @@ import org.apache.spark.sql.catalyst.expressions.{Expression, Literal}
  * A Decimal that must have fixed precision (the maximum number of digits) and scale (the number
  * of digits on right side of dot).
  *
- * The precision can be up to 38, scale can also be up to 38 (less or equal to precision).
+ * The precision can be up to 127, scale can also be up to 127 (less or equal to precision).
  *
  * The default precision and scale is (10, 0).
  *
@@ -48,7 +48,7 @@ case class DecimalType(precision: Int, scale: Int) extends FractionalType {
   }
 
   if (precision > DecimalType.MAX_PRECISION) {
-    throw new AnalysisException(s"DecimalType can only support precision up to 38")
+    throw new AnalysisException(s"DecimalType can only support precision up to ${DecimalType.MAX_PRECISION}")
   }
 
   // default constructor for Java

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/json/JsonInferSchema.scala

@@ -279,8 +279,8 @@ private[sql] object JsonInferSchema {
         case (t1: DecimalType, t2: DecimalType) =>
           val scale = math.max(t1.scale, t2.scale)
           val range = math.max(t1.precision - t1.scale, t2.precision - t2.scale)
-          if (range + scale > 38) {
-            // DecimalType can't support precision > 38
+          if (range + scale > DecimalType.MAX_PRECISION) {
+            // DecimalType can't support precision > DecimalType.MAX_PRECISION
             DoubleType
           } else {
             DecimalType(range + scale, scale)

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetSchemaConverter.scala

@@ -594,7 +594,7 @@ private[sql] object ParquetSchemaConverter {
   }
 
   // Returns the minimum number of bytes needed to store a decimal with a given `precision`.
-  val minBytesForPrecision = Array.tabulate[Int](39)(computeMinBytesForPrecision)
+  val minBytesForPrecision = Array.tabulate[Int](DecimalType.MAX_PRECISION + 1)(computeMinBytesForPrecision)
 
   // Max precision of a decimal value stored in `numBytes` bytes
   def maxPrecisionForBytes(numBytes: Int): Int = {