Add ability to skip decoding in deserializer

Author: oschwald

decoder.go

@@ -65,6 +65,14 @@ func (d *decoder) decodeToDeserializer(offset uint, dser deserializer, depth int
 		return 0, err
 	}
 
+	skip, err := dser.ShouldSkip(uintptr(offset))
+	if err != nil {
+		return 0, err
+	}
+	if skip {
+		return d.nextValueOffset(offset, 1)
+	}
+
 	return d.decodeFromTypeToDeserializer(typeNum, size, newOffset, dser, depth+1)
 }
 

deserializer.go

@@ -14,8 +14,9 @@ import "math/big"
 // It is not currently covered by any Semantic Versioning guarantees.
 // Use at your own risk.
 type deserializer interface {
-	StartSlice(uint) error
-	StartMap(uint) error
+	ShouldSkip(offset uintptr) (bool, error)
+	StartSlice(size uint) error
+	StartMap(size uint) error
 	End() error
 	String(string) error
 	Float64(float64) error