Implemented encode and decodeBinaryXMLContentObject
diff --git a/ndn-cpp/c/encoding/BinaryXMLContentObject.c b/ndn-cpp/c/encoding/BinaryXMLContentObject.c
index 820ff41..ef50532 100644
--- a/ndn-cpp/c/encoding/BinaryXMLContentObject.c
+++ b/ndn-cpp/c/encoding/BinaryXMLContentObject.c
@@ -10,12 +10,181 @@
 #include "BinaryXMLPublisherPublicKeyDigest.h"
 #include "BinaryXMLContentObject.h"
 
+static ndn_Error encodeSignature(struct ndn_Signature *signature, struct ndn_BinaryXMLEncoder *encoder)
+{
+  ndn_Error error;
+  if (error = ndn_BinaryXMLEncoder_writeElementStartDTag(encoder, ndn_BinaryXML_DTag_Signature))
+    return error;
+  
+  // TODO: Check if digestAlgorithm is the same as the default, and skip it, otherwise encode it as UDATA.
+
+  if (error = ndn_BinaryXMLEncoder_writeOptionalBlobDTagElement
+      (encoder, ndn_BinaryXML_DTag_Witness, signature->witness, signature->witnessLength))
+    return error;
+
+  // Require a signature.
+  if (error = ndn_BinaryXMLEncoder_writeBlobDTagElement
+      (encoder, ndn_BinaryXML_DTag_SignatureBits, signature->signature, signature->signatureLength))
+    return error;
+  
+	if (error = ndn_BinaryXMLEncoder_writeElementClose(encoder))
+    return error;
+  
+  return 0;    
+}
+
+static ndn_Error decodeSignature(struct ndn_Signature *signature, struct ndn_BinaryXMLDecoder *decoder)
+{
+  ndn_Error error;
+  if (error = ndn_BinaryXMLDecoder_readElementStartDTag(decoder, ndn_BinaryXML_DTag_Signature))
+    return error;
+  
+  /* TODO: digestAlgorithm as UDATA */ signature->digestAlgorithm = 0; signature->digestAlgorithmLength = 0;
+  
+  if (error = ndn_BinaryXMLDecoder_readOptionalBinaryDTagElement
+      (decoder, ndn_BinaryXML_DTag_Witness, 0, &signature->witness, &signature->witnessLength))
+    return error;
+  
+  // Require a signature.
+  if (error = ndn_BinaryXMLDecoder_readBinaryDTagElement
+      (decoder, ndn_BinaryXML_DTag_SignatureBits, 0, &signature->signature, &signature->signatureLength))
+    return error;
+  
+  if (error = ndn_BinaryXMLDecoder_readElementClose(decoder))
+    return error;
+  
+  return 0;
+}
+
+static ndn_Error encodeSignedInfo(struct ndn_SignedInfo *signedInfo, struct ndn_BinaryXMLEncoder *encoder)
+{
+  if (signedInfo->type < 0)
+    return;
+
+  ndn_Error error;
+  if (error = ndn_BinaryXMLEncoder_writeElementStartDTag(encoder, ndn_BinaryXML_DTag_SignedInfo))
+    return error;
+
+  // This will skip encoding if there is no publisherPublicKeyDigest.
+  if (error = ndn_encodeBinaryXMLPublisherPublicKeyDigest(&signedInfo->publisherPublicKeyDigest, encoder))
+    return error;
+  
+  // TODO: Implement timeStamp  
+  
+  if (signedInfo->type != ndn_ContentType_DATA) {
+    // Not the default of DATA, so we need to encode the type.
+    // TODO: Implement converting the type from an int and encoding.
+  }
+  
+  if (error = ndn_BinaryXMLEncoder_writeOptionalUnsignedDecimalIntDTagElement
+      (encoder, ndn_BinaryXML_DTag_FreshnessSeconds, signedInfo->freshnessSeconds))
+    return error;
+  
+  if (error = ndn_BinaryXMLEncoder_writeOptionalBlobDTagElement
+      (encoder, ndn_BinaryXML_DTag_FinalBlockID, signedInfo->finalBlockID, signedInfo->finalBlockIDLength))
+    return error;
+ 
+  // This will skip encoding if there is no key locator.
+  if (error = ndn_encodeBinaryXMLKeyLocator(&signedInfo->keyLocator, encoder))
+    return error;
+  
+	if (error = ndn_BinaryXMLEncoder_writeElementClose(encoder))
+    return error;
+  
+  return 0;  
+}
+
+static ndn_Error decodeSignedInfo(struct ndn_SignedInfo *signedInfo, struct ndn_BinaryXMLDecoder *decoder)
+{
+  ndn_Error error;
+  if (error = ndn_BinaryXMLDecoder_readElementStartDTag(decoder, ndn_BinaryXML_DTag_SignedInfo))
+    return error;
+  
+  if (error = ndn_decodeOptionalBinaryXMLPublisherPublicKeyDigest(&signedInfo->publisherPublicKeyDigest, decoder))
+    return error;
+  
+  // TODO: Implement timeStamp
+  
+  // TODO: Implement reading the type and converting to an int.
+  signedInfo->type = ndn_ContentType_DATA;
+ 
+  if (error = ndn_BinaryXMLDecoder_readOptionalUnsignedIntegerDTagElement
+      (decoder, ndn_BinaryXML_DTag_FreshnessSeconds, &signedInfo->freshnessSeconds))
+    return error;
+
+  if (error = ndn_BinaryXMLDecoder_readOptionalBinaryDTagElement
+      (decoder, ndn_BinaryXML_DTag_FinalBlockID, 0, &signedInfo->finalBlockID, &signedInfo->finalBlockIDLength))
+    return error;
+
+  if (error = ndn_decodeOptionalBinaryXMLKeyLocator(&signedInfo->keyLocator, decoder))
+    return error;
+  
+  if (error = ndn_BinaryXMLDecoder_readElementClose(decoder))
+    return error;
+  
+  return 0;
+}
+
 ndn_Error ndn_encodeBinaryXMLContentObject(struct ndn_ContentObject *contentObject, struct ndn_BinaryXMLEncoder *encoder)
 {
+  ndn_Error error;
+  if (error = ndn_BinaryXMLEncoder_writeElementStartDTag(encoder, ndn_BinaryXML_DTag_ContentObject))
+    return error;
+  
+  if (error = encodeSignature(&contentObject->signature, encoder))
+    return 0;
+
+  if (error = ndn_encodeBinaryXMLName(&contentObject->name, encoder))
+    return error;
+
+  if (error = encodeSignedInfo(&contentObject->signedInfo, encoder))
+    return 0;
+
+  if (error = ndn_BinaryXMLEncoder_writeBlobDTagElement
+      (encoder, ndn_BinaryXML_DTag_Content, contentObject->content, contentObject->contentLength))
+    return error;
+  
+	if (error = ndn_BinaryXMLEncoder_writeElementClose(encoder))
+    return error;
+  
   return 0;
 }
 
 ndn_Error ndn_decodeBinaryXMLContentObject(struct ndn_ContentObject *contentObject, struct ndn_BinaryXMLDecoder *decoder)
 {
+  ndn_Error error;
+  if (error = ndn_BinaryXMLDecoder_readElementStartDTag(decoder, ndn_BinaryXML_DTag_ContentObject))
+    return error;
+
+  int gotExpectedTag;
+  if (error = ndn_BinaryXMLDecoder_peekDTag(decoder, ndn_BinaryXML_DTag_Signature, &gotExpectedTag))
+    return error;
+  if (gotExpectedTag) {
+    if (error = decodeSignature(&contentObject->signature, decoder))
+      return error;
+  }
+  else
+    ndn_Signature_init(&contentObject->signature);
+  
+  if (error = ndn_decodeBinaryXMLName(&contentObject->name, decoder))
+    return error;
+  
+  if (error = ndn_BinaryXMLDecoder_peekDTag(decoder, ndn_BinaryXML_DTag_SignedInfo, &gotExpectedTag))
+    return error;
+  if (gotExpectedTag) {
+    if (error = decodeSignedInfo(&contentObject->signedInfo, decoder))
+      return error;
+  }
+  else
+    ndn_SignedInfo_init(&contentObject->signedInfo);
+
+  // Require a Content element, but set allowNull to allow a missing BLOB.
+  if (error = ndn_BinaryXMLDecoder_readBinaryDTagElement
+      (decoder, ndn_BinaryXML_DTag_Content, 1, &contentObject->content, &contentObject->contentLength))
+    return error; 
+  
+  if (error = ndn_BinaryXMLDecoder_readElementClose(decoder))
+    return error;
+  
   return 0;
 }