Adds a first version of a new obidistribute command

pkg/obiseq/class.go

@@ -0,0 +1,65 @@
+package obiseq
+
+import (
+	"fmt"
+	"hash/crc32"
+	"strconv"
+)
+
+type SequenceClassifier func(sequence BioSequence) string
+
+func AnnotationClassifier(key string) SequenceClassifier {
+	f := func(sequence BioSequence) string {
+		if sequence.HasAnnotation() {
+			value, ok := sequence.Annotations()[key]
+
+			if ok {
+				switch value := value.(type) {
+				case string:
+					return value
+				default:
+					return fmt.Sprint(value)
+				}
+			}
+		}
+		return ""
+	}
+
+	return SequenceClassifier(f)
+}
+
+var SampleClassifier = AnnotationClassifier("sample")
+
+func PredicateClassifier(predicate SequencePredicate) SequenceClassifier {
+	f := func(sequence BioSequence) string {
+		if predicate(sequence) {
+			return "true"
+		} else {
+			return "false"
+		}
+	}
+
+	return SequenceClassifier(f)
+}
+
+// Builds a classifier function based on CRC32 of the sequence
+//
+func HashClassifier(size int) SequenceClassifier {
+	f := func(sequence BioSequence) string {
+		h := crc32.ChecksumIEEE(sequence.Sequence()) % uint32(size)
+		return strconv.Itoa(int(h))
+	}
+
+	return SequenceClassifier(f)
+}
+
+func RotateClassifier(size int) SequenceClassifier {
+	n := 0
+	f := func(sequence BioSequence) string {
+		h := n % size
+		n++
+		return strconv.Itoa(int(h))
+	}
+
+	return SequenceClassifier(f)
+}