Add ReadDecimal helper

binlog/event_rows.go

@@ -174,9 +174,7 @@ func (e *RowsEvent) decodeValue(buf *buffer.Buffer, ct mysql.ColumnType, meta ui
 	case mysql.ColumnTypeNewDecimal:
 		precision := int(meta >> 8)
 		decimals := int(meta & 0xFF)
-		dec, n := mysql.DecodeDecimal(buf.Cur(), precision, decimals)
-		buf.Skip(n)
-		return dec
+		return buf.ReadDecimal(precision, decimals)
 
 	// Date and Time
 	case mysql.ColumnTypeYear:

buffer/buffer.go

@@ -170,3 +170,15 @@ func (b *Buffer) WriteStringLenEnc(s string) {
 func (b *Buffer) WriteStringEOF(s string) {
 	b.pos += copy(b.data[b.pos:], s)
 }
+
+//
+// Special types
+//
+
+// ReadDecimal decodes a decimal value from the buffer anf then advances cursor
+// accordingly.
+func (b *Buffer) ReadDecimal(precision, decimals int) mysql.Decimal {
+	dec, n := mysql.DecodeDecimal(b.Cur(), precision, decimals)
+	b.Skip(n)
+	return dec
+}