Adding flatfile.RecReader interface - the primary data reading and record matching interface a new flat file format reader should implement.

extensions/omniv21/fileformat/flatfile/recreader.go

@@ -0,0 +1,36 @@
+package flatfile
+
+import (
+"github.com/jf-tech/omniparser/idr"
+)
+
+// RecReader defines an interface for a flat file specific format to read data and match
+// a RecDecl.
+type RecReader interface {
+// MoreUnprocessedData indicates whether there is any unprocessed data left in the input
+// stream. Possible return values:
+// - (true, nil): more data is available.
+// - (false, nil): no more data is available.
+// - (_, err): some and most likely fatal IO error has occurred.
+// Implementation notes:
+// - If some data is read in and io.EOF is encountered, (true, nil) should be returned.
+// - If no data is read in and io.EOF is encountered, (false, nil) should be returned.
+// - Under no circumstances, io.EOF should be returned.
+// - Once a call to this method returns (false, nil), all future calls to it should always
+// return (false, nil).
+MoreUnprocessedData() (more bool, err error)
+
+// ReadAndMatch matches the passed-in RecDecl to unprocessed data and creates a
+// corresponding IDR node if data matches and createIDR flag is turned on.
+// Implementation notes:
+// - If io.EOF is encountered while there is still unmatched thus unprocessed data,
+// io.EOF shouldn't be returned.
+// - If a non io.EOF error encountered during IO, return (false, nil, err).
+// - If the decl is a Group(), the matching should be using the recursive algorithm
+// to match the first-heir-in-line non-group descendent decl. If matched, the returned
+// IDR node should be of this group node, and the actual matched record data should be
+// internally cached for the next call(s). This logic is similar to the EDI segment
+// matching logic:
+// https://github.com/jf-tech/omniparser/blob/6802ed98d0e5325a6908ebbc6d2da0e4655ed125/extensions/omniv21/fileformat/edi/seg.go#L87
+ReadAndMatch(decl RecDecl, createIDR bool) (matched bool, node *idr.Node, err error)
+}