generic json for fix messages

quickfix/field_map.go

@@ -89,6 +89,24 @@ func (m FieldMap) Get(parser Field) MessageRejectError {
 	return m.GetField(parser.Tag(), parser)
 }
 
+// RawValues returns a copy of the underlying TagValue slice for a tag.
+// For repeating groups, the first entry is the count and the remaining
+// entries are the flattened inner-field values across all repetitions.
+func (m FieldMap) RawValues(tag Tag) []TagValue {
+	m.rwLock.RLock()
+	defer m.rwLock.RUnlock()
+
+	f, ok := m.tagLookup[tag]
+	if !ok {
+		return nil
+	}
+
+	out := make([]TagValue, len(f))
+	copy(out, f)
+
+	return out
+}
+
 // Has returns true if the Tag is present in this FieldMap.
 func (m FieldMap) Has(tag Tag) bool {
 	m.rwLock.RLock()