diff --git a/ndn-cpp/Interest.cpp b/ndn-cpp/Interest.cpp
index b99c3cd..d081620 100644
--- a/ndn-cpp/Interest.cpp
+++ b/ndn-cpp/Interest.cpp
@@ -30,7 +30,7 @@
       (nonce_.begin(), interestStruct.nonce, interestStruct.nonce + interestStruct.nonceLength);
 }
 
-void Interest::get(struct ndn_Interest &interestStruct) 
+void Interest::get(struct ndn_Interest &interestStruct) const 
 {
   name_.get(interestStruct.name);
   interestStruct.minSuffixComponents = minSuffixComponents_;
@@ -38,7 +38,7 @@
   
   interestStruct.publisherPublicKeyDigestLength = publisherPublicKeyDigest_.size();
   if (publisherPublicKeyDigest_.size() > 0)
-    interestStruct.publisherPublicKeyDigest = &publisherPublicKeyDigest_[0];
+    interestStruct.publisherPublicKeyDigest = (unsigned char *)&publisherPublicKeyDigest_[0];
   else
     interestStruct.publisherPublicKeyDigest = 0;
   
@@ -51,7 +51,7 @@
 
   interestStruct.nonceLength = nonce_.size();
   if (nonce_.size() > 0)
-    interestStruct.nonce = &nonce_[0];
+    interestStruct.nonce = (unsigned char *)&nonce_[0];
   else
     interestStruct.nonce = 0;
 }
diff --git a/ndn-cpp/Interest.hpp b/ndn-cpp/Interest.hpp
index 01681be..1d63db8 100644
--- a/ndn-cpp/Interest.hpp
+++ b/ndn-cpp/Interest.hpp
@@ -14,11 +14,11 @@
 
 class Interest {
 public:    
-  void encode(std::vector<unsigned char> &output, WireFormat &wireFormat) 
+  void encode(std::vector<unsigned char> &output, WireFormat &wireFormat) const 
   {
     wireFormat.encodeInterest(*this, output);
   }
-  void encode(std::vector<unsigned char> &output) 
+  void encode(std::vector<unsigned char> &output) const 
   {
     encode(output, BinaryXMLWireFormat::instance());
   }
@@ -44,11 +44,15 @@
    * WARNING: The resulting pointers in interestStruct are invalid after a further use of this object which could reallocate memory.
    * @param interestStruct a C ndn_Interest struct where the name components array is already allocated.
    */
-  void get(struct ndn_Interest &interestStruct);
+  void get(struct ndn_Interest &interestStruct) const;
 
-  Name &getName() { return name_; }
+  const Name &getName() const { return name_; }
   
-  int getInterestLifetime() { return interestLifetime_; }
+  int getMinSuffixComponents() const { return minSuffixComponents_; }
+  
+  int getMaxSuffixComponents() const { return maxSuffixComponents_; }
+
+  int getInterestLifetime() const { return interestLifetime_; }
   
   /**
    * Clear this interest, and set the values by copying from the interest struct.
diff --git a/ndn-cpp/Name.cpp b/ndn-cpp/Name.cpp
index a5c8ade..f80d1a7 100644
--- a/ndn-cpp/Name.cpp
+++ b/ndn-cpp/Name.cpp
@@ -226,7 +226,7 @@
   }
 }
 
-void Name::get(struct ndn_Name &nameStruct) 
+void Name::get(struct ndn_Name &nameStruct) const
 {
   if (nameStruct.maxComponents < components_.size())
     throw runtime_error("nameStruct.maxComponents must be >= this name getNComponents()");
@@ -243,7 +243,7 @@
     addComponent(nameStruct.components[i].value, nameStruct.components[i].valueLength);  
 }
 
-std::string Name::to_uri()
+std::string Name::to_uri() const
 {
   if (components_.size() == 0)
     return "/";
diff --git a/ndn-cpp/Name.hpp b/ndn-cpp/Name.hpp
index fbb28d0..0d43e93 100644
--- a/ndn-cpp/Name.hpp
+++ b/ndn-cpp/Name.hpp
@@ -29,9 +29,9 @@
    * WARNING: The resulting pointer in componentStruct is invalid after a further use of this object which could reallocate memory.
    * @param componentStruct the C ndn_NameComponent struct to receive the pointer.
    */
-  void get(struct ndn_NameComponent &componentStruct) 
+  void get(struct ndn_NameComponent &componentStruct) const 
   {
-    componentStruct.value = &value_[0];
+    componentStruct.value = (unsigned char *)&value_[0];
     componentStruct.valueLength = value_.size(); 
   }
   
@@ -65,11 +65,11 @@
    */
   Name(const char *uri);
   
-  void encode(std::vector<unsigned char> &output, WireFormat &wireFormat) 
+  void encode(std::vector<unsigned char> &output, WireFormat &wireFormat) const
   {
     wireFormat.encodeName(*this, output);
   }
-  void encode(std::vector<unsigned char> &output) 
+  void encode(std::vector<unsigned char> &output) const 
   {
     encode(output, BinaryXMLWireFormat::instance());
   }
@@ -95,7 +95,7 @@
    * WARNING: The resulting pointers in nameStruct are invalid after a further use of this object which could reallocate memory.
    * @param nameStruct a C ndn_Name struct where the components array is already allocated.
    */
-  void get(struct ndn_Name &nameStruct);
+  void get(struct ndn_Name &nameStruct) const;
   
   /**
    * Clear this name, and set the components by copying from the name struct.
@@ -121,7 +121,7 @@
    * Get the number of components.
    * @return the number of components
    */
-  unsigned int getComponentCount() {
+  unsigned int getComponentCount() const {
     return components_.size();
   }
   
@@ -131,7 +131,7 @@
    * Encode this name as a URI.
    * @return the encoded URI.
    */
-  std::string to_uri();
+  std::string to_uri() const;
   
 private:
   std::vector<NameComponent> components_;
diff --git a/ndn-cpp/encoding/BinaryXMLStructureDecoder.hpp b/ndn-cpp/encoding/BinaryXMLStructureDecoder.hpp
index ad562ff..8c39cf1 100644
--- a/ndn-cpp/encoding/BinaryXMLStructureDecoder.hpp
+++ b/ndn-cpp/encoding/BinaryXMLStructureDecoder.hpp
@@ -37,8 +37,8 @@
     return gotElementEnd();
   }
   
-  unsigned int getOffset() { return base_.offset; }
-  bool gotElementEnd() { return base_.gotElementEnd != 0; }
+  unsigned int getOffset() const { return base_.offset; }
+  bool gotElementEnd() const { return base_.gotElementEnd != 0; }
   
 private:
   struct ndn_BinaryXMLStructureDecoder base_;
diff --git a/ndn-cpp/encoding/BinaryXMLWireFormat.cpp b/ndn-cpp/encoding/BinaryXMLWireFormat.cpp
index a92237e..2cb6de6 100644
--- a/ndn-cpp/encoding/BinaryXMLWireFormat.cpp
+++ b/ndn-cpp/encoding/BinaryXMLWireFormat.cpp
@@ -17,7 +17,7 @@
 
 BinaryXMLWireFormat BinaryXMLWireFormat::instance_;
 
-void BinaryXMLWireFormat::encodeName(Name &name, vector<unsigned char> &output) 
+void BinaryXMLWireFormat::encodeName(const Name &name, vector<unsigned char> &output) 
 {
   struct ndn_Name nameStruct;
   struct ndn_NameComponent components[100];
@@ -46,7 +46,7 @@
   name.set(nameStruct);
 }
 
-void BinaryXMLWireFormat::encodeInterest(Interest &interest, vector<unsigned char> &output) 
+void BinaryXMLWireFormat::encodeInterest(const Interest &interest, vector<unsigned char> &output) 
 {
   struct ndn_Interest interestStruct;
   struct ndn_NameComponent components[100];
diff --git a/ndn-cpp/encoding/BinaryXMLWireFormat.hpp b/ndn-cpp/encoding/BinaryXMLWireFormat.hpp
index 5b3d065..ad3a88c 100644
--- a/ndn-cpp/encoding/BinaryXMLWireFormat.hpp
+++ b/ndn-cpp/encoding/BinaryXMLWireFormat.hpp
@@ -12,10 +12,10 @@
 
 class BinaryXMLWireFormat : public WireFormat {
 public:
-  virtual void encodeName(Name &name, std::vector<unsigned char> &output);
+  virtual void encodeName(const Name &name, std::vector<unsigned char> &output);
   virtual void decodeName(Name &name, const unsigned char *input, unsigned int inputLength);
 
-  virtual void encodeInterest(Interest &interest, std::vector<unsigned char> &output);
+  virtual void encodeInterest(const Interest &interest, std::vector<unsigned char> &output);
   virtual void decodeInterest(Interest &interest, const unsigned char *input, unsigned int inputLength);
   
   static BinaryXMLWireFormat &instance() { return instance_; }
diff --git a/ndn-cpp/encoding/WireFormat.cpp b/ndn-cpp/encoding/WireFormat.cpp
index f3906fd..3217fe1 100644
--- a/ndn-cpp/encoding/WireFormat.cpp
+++ b/ndn-cpp/encoding/WireFormat.cpp
@@ -10,7 +10,7 @@
 
 namespace ndn {
   
-void WireFormat::encodeName(Name &name, vector<unsigned char> &output) 
+void WireFormat::encodeName(const Name &name, vector<unsigned char> &output) 
 {
   throw logic_error("unimplemented");
 }
@@ -19,7 +19,7 @@
   throw logic_error("unimplemented");
 }
 
-void WireFormat::encodeInterest(Interest &interest, vector<unsigned char> &output) 
+void WireFormat::encodeInterest(const Interest &interest, vector<unsigned char> &output) 
 {
   throw logic_error("unimplemented");
 }
diff --git a/ndn-cpp/encoding/WireFormat.hpp b/ndn-cpp/encoding/WireFormat.hpp
index d9811cd..f09ae22 100644
--- a/ndn-cpp/encoding/WireFormat.hpp
+++ b/ndn-cpp/encoding/WireFormat.hpp
@@ -15,10 +15,10 @@
   
 class WireFormat {
 public:
-  virtual void encodeName(Name &name, std::vector<unsigned char> &output);
+  virtual void encodeName(const Name &name, std::vector<unsigned char> &output);
   virtual void decodeName(Name &name, const unsigned char *input, unsigned int inputLength);
 
-  virtual void encodeInterest(Interest &interest, std::vector<unsigned char> &output);
+  virtual void encodeInterest(const Interest &interest, std::vector<unsigned char> &output);
   virtual void decodeInterest(Interest &interest, const unsigned char *input, unsigned int inputLength);
 
   // etc. for each type of object.