Add GetPolynomialForm method

Signed-off-by: litt3 <102969658+litt3@users.noreply.github.com>

api/clients/codecs/blob_codec.go

@@ -27,16 +27,15 @@ const (
 func EncodePayload(payload []byte) []byte {
 	payloadHeader := make([]byte, 32)
 	// first byte is always 0 to ensure the payloadHeader is a valid bn254 element
-	// encode version byte
-	payloadHeader[1] = byte(DefaultBlobEncoding)
+	payloadHeader[1] = byte(DefaultBlobEncoding) // encode version byte
 
 	// encode payload length as uint32
 	binary.BigEndian.PutUint32(
 		payloadHeader[2:6],
 		uint32(len(payload))) // uint32 should be more than enough to store the length (approx 4gb)
 
 	// encode payload modulo bn254
-	// the resulting bytes are subsequently treated as the evaluation of a polynomial
+	// the resulting bytes subsequently may be treated as the evaluation of a polynomial
 	polynomialEval := codec.ConvertByPaddingEmptyByte(payload)
 
 	encodedPayload := append(payloadHeader, polynomialEval...)
@@ -56,10 +55,9 @@ func DecodePayload(encodedPayload []byte) ([]byte, error) {
 	payloadLength := binary.BigEndian.Uint32(encodedPayload[2:6])
 
 	// decode raw data modulo bn254
-	decodedData := codec.RemoveEmptyByteFromPaddedBytes(encodedPayload[32:])
+	nonPaddedData := codec.RemoveEmptyByteFromPaddedBytes(encodedPayload[32:])
 
-	// get non blob header data
-	reader := bytes.NewReader(decodedData)
+	reader := bytes.NewReader(nonPaddedData)
 	payload := make([]byte, payloadLength)
 	readLength, err := reader.Read(payload)
 	if err != nil {

api/clients/eigenda_client.go

@@ -28,6 +28,7 @@ import (
 type IEigenDAClient interface {
 	GetBlob(ctx context.Context, batchHeaderHash []byte, blobIndex uint32) ([]byte, error)
 	PutBlob(ctx context.Context, txData []byte) (*grpcdisperser.BlobInfo, error)
+	GetPolynomialForm() codecs.PolynomialForm
 	Close() error
 }
 
@@ -131,6 +132,14 @@ func NewEigenDAClient(log log.Logger, config EigenDAClientConfig) (*EigenDAClien
 	}, nil
 }
 
+// GetPolynomialForm returns the form of polynomials, as they are distributed in the system
+//
+// The polynomial form indicates how blobs must be constructed before dispersal, and how received blobs ought to be
+// interpreted.
+func (m *EigenDAClient) GetPolynomialForm() codecs.PolynomialForm {
+	return m.PolynomialForm
+}
+
 // GetBlob retrieves a blob from the EigenDA service using the provided context,
 // batch header hash, and blob index.  If decode is set to true, the function
 // decodes the retrieved blob data. If set to false it returns the encoded blob