func()

in transforms.go [370:424]

• 46 lines of code
• 10 McCabe index (conditional complexity)

func (t TruncateTransform) Transformer(src Type) (func(any) any, error) {
	switch src.(type) {
	case Int32Type:
		return func(v any) any {
			if v == nil {
				return nil
			}

			val := v.(int32)

			return val - (val % int32(t.Width))
		}, nil
	case Int64Type:
		return func(v any) any {
			if v == nil {
				return nil
			}

			val := v.(int64)

			return val - (val % int64(t.Width))
		}, nil
	case StringType, BinaryType:
		return func(v any) any {
			switch v := v.(type) {
			case string:
				return v[:min(len(v), t.Width)]
			case []byte:
				return v[:min(len(v), t.Width)]
			default:
				return nil
			}
		}, nil
	case DecimalType:
		bigWidth := big.NewInt(int64(t.Width))

		return func(v any) any {
			if v == nil {
				return nil
			}

			val := v.(Decimal)
			unscaled := val.Val.BigInt()
			// unscaled - (((unscaled % width) + width) % width)
			applied := (&big.Int{}).Mod(unscaled, bigWidth)
			applied.Add(applied, bigWidth).Mod(applied, bigWidth)
			val.Val = decimal128.FromBigInt(unscaled.Sub(unscaled, applied))

			return val
		}, nil
	}

	return nil, fmt.Errorf("%w: cannot truncate for type %s",
		ErrInvalidArgument, src)
}