add a translator from endpoint index to number

LibUSB::InterfaceImpl::getEndpoint() throws a logic_error exception
if the index and endpoint number are not equal. This presents a
problem communicating with a USB device, based on the Cypress
CY7C68001 chip which only implements endpoint numbers 2, 4, 6 and 8
in addition to 0.

Libusbpp had incorrectly made a assumption that all USB devices have
linear endpoint numbering. The Libusbpp should be handled the linear
and non linear numbering in same way.

LibUSB::Interface{Impl}::getEndpoint() has been refectored to expect
a number (not a index) explicitly.

LibUSB::Interface{Impl}::getEPNumberByIndex() is a new public method
to translate a given endpoint index to the corresponding endpoint
number. This number can be used together with getEndpoint() to get
the corresponding endpoint object in a fast way.

Example:

    std::shared_ptr<LibUSB::Interface> pInterface = /* ... */
    for (int epidx = 1;
             epidx <= pInterface->NumEndpoints();
             epidx++)
    {
        std::shared_ptr<LibUSB::Endpoint> pEndpoint;
        pEndpoint = pInterface->getEndpoint(
                    pInterface->getEPNumberByIndex(epidx)
            );

        /* ... */
    }

A new use case for getEPNumberByIndex() is the creation of a map of
endpoint numbers by it corresponding index as a key. Walk throught
such a list gives access to all available endpoint numbers
independent of a specific context.

Example:

    typedef std::map<int, int> EndpointNumbers_t;
    EndpointNumbers_t mEndpointNumbers;

    std::shared_ptr<LibUSB::Interface> pInterface = /* ... */
    for (int epidx = 1;
             epidx <= pInterface->NumEndpoints();
             epidx++)
    {

        mEndpointNumbers.insert(
            std::make_pair(
                epidx, pInterface->getEPNumberByIndex( epidx )
            )
        );

    }

    /* ... */

    for (const auto &epnum : mEndpointNumbers)
    {
        std::shared_ptr<LibUSB::Endpoint> pEndpoint;
        pEndpoint =pInterface->getEndpoint(epnum.second);

        /* ... */
    }

Based on this concept the interface class provides the new public
method LibUSB::Interface::getEndpointNumbers() to reduce the effort
for the user.

Example (the same as befor, but just simpler):

    std::shared_ptr<LibUSB::Interface> pInterface = /* ... */

    LibUSB::Interface::EndpointNumbers_t mEndpointNumbers;
    mEndpointNumbers = pInterface->getEndpointNumbers();

    /* ... */

    for (const auto &epnum : mEndpointNumbers)
    {
        std::shared_ptr<LibUSB::Endpoint> pEndpoint;
        pEndpoint =pInterface->getEndpoint(epnum.second);

        /* ... */
    }

Related-to-issue: zarthcode#3
Signed-off-by: Stephan Linz <[email protected]>

examples/LibusbTest.cpp

@@ -239,11 +239,12 @@ int main(int argc, char* argv[])
 						std::wcout << L"\t\tInterface descriptor:" << pInterface->DescriptorString() << std::endl;
 						std::wcout << L"\t\tInterface Number of endpoints: " << std::dec << pInterface->NumEndpoints() << std::endl << std::endl;
 
-						// Iterate over the interface endpoints (other than ep0!!)
-						for (int epnum = 1; epnum <= pInterface->NumEndpoints(); epnum++)
+						// Iterate over the interface endpoints (other than ep0!!) - by the index to number map
+						LibUSB::Interface::EndpointNumbers_t mEndpointNumbers = pInterface->getEndpointNumbers();
+						for (const auto &epnum : mEndpointNumbers)
 						{
 
-							std::shared_ptr<LibUSB::Endpoint> pEndpoint = pInterface->getEndpoint(epnum);
+							std::shared_ptr<LibUSB::Endpoint> pEndpoint = pInterface->getEndpoint(epnum.second);
 
 							/// Endpoint information
 							std::wcout << L"\t\t\tEndpoint number: " << std::dec << pEndpoint->Number() << std::endl;

headers/libusbpp/Interface.hpp

@@ -21,8 +21,9 @@
 #ifndef LIBUSBPP_INTERFACE_HPP
 #define LIBUSBPP_INTERFACE_HPP
 
-#include <memory>
 #include <string>
+#include <memory>
+#include <map>
 
 #include <stdint.h>
 
@@ -78,8 +79,17 @@ namespace LibUSB
 		/// Returns the number of endpoints this interface has.
 		int NumEndpoints()const;
 
+		/// Returns the number of a specified endpoint
+		int getEPNumberByIndex(int index)const;
+
+		/// Endpoint number container type (index -> number)
+		typedef std::map<int, int> EndpointNumbers_t;
+
+		/// Returns the number container of all endpoint indices
+		EndpointNumbers_t getEndpointNumbers()const;
+
 		/// Returns the specified endpoint
-		std::shared_ptr<Endpoint> getEndpoint(int index);
+		std::shared_ptr<Endpoint> getEndpoint(int number);
 
 	protected:
 	private:

src/Interface.cpp

@@ -103,9 +103,27 @@ int LibUSB::Interface::NumEndpoints() const
 	return m_pInterfaceImpl->NumEndpoints();
 }
 
-std::shared_ptr<LibUSB::Endpoint> LibUSB::Interface::getEndpoint( int index )
+int LibUSB::Interface::getEPNumberByIndex( int index ) const
 {
-	return m_pInterfaceImpl->getEndpoint(index);
+	return m_pInterfaceImpl->getEPNumberByIndex(index);
+}
+
+LibUSB::Interface::EndpointNumbers_t LibUSB::Interface::getEndpointNumbers() const
+{
+	EndpointNumbers_t mEndpointNumbers;
+
+	// Create each endpoint number
+	for (int i = 1; i <= NumEndpoints(); i++)
+	{
+		mEndpointNumbers.insert(std::make_pair(i,getEPNumberByIndex(i)));
+	}
+
+	return mEndpointNumbers;
+}
+
+std::shared_ptr<LibUSB::Endpoint> LibUSB::Interface::getEndpoint( int number )
+{
+	return m_pInterfaceImpl->getEndpoint(number);
 }
 
 bool LibUSB::Interface::isClaimed() const

src/InterfaceImpl.cpp

@@ -280,9 +280,50 @@ uint8_t LibUSB::InterfaceImpl::NumEndpoints() const
 	return m_pInterface->altsetting[m_alternateSetting].bNumEndpoints;
 }
 
-std::shared_ptr<LibUSB::Endpoint> LibUSB::InterfaceImpl::getEndpoint( uint8_t index )
+uint8_t LibUSB::InterfaceImpl::getEPNumberByIndex( uint8_t index ) const
 {
 	if (index == 0)
+	{
+		// Return the number zero of the device control endpoint.
+		return index;
+	}
+
+
+	if (index > NumEndpoints())
+	{
+		throw std::logic_error("LibUSB::InterfaceImpl::getEPNumberByIndex() - index out of range.");
+	}
+
+
+	// Find the number of endpoint
+	EndpointContainer_t::const_iterator itEndpoint = m_EndpointContainer.begin();
+	std::advance(itEndpoint, index - 1);
+
+	std::shared_ptr<LibUSB::Endpoint> pEndpoint;
+	if (itEndpoint != m_EndpointContainer.end())
+	{
+
+		pEndpoint = itEndpoint->second;
+
+		/// \note #2 Validate endpoint number.
+		if (!pEndpoint->Number())
+		{
+			throw std::logic_error("LibUSB::InterfaceImpl::getEPNumberByIndex() - endpoint has no number as expected! (note #2)");
+		}
+
+	}
+	else
+	{
+		throw std::logic_error("LibUSB::InterfaceImpl::getEPNumberByIndex() - endpoint not found.");
+	}
+
+
+	return pEndpoint->Number();
+}
+
+std::shared_ptr<LibUSB::Endpoint> LibUSB::InterfaceImpl::getEndpoint( uint8_t number )
+{
+	if (number == 0)
 	{
 
 		// Return the device control endpoint zero.
@@ -296,26 +337,21 @@ std::shared_ptr<LibUSB::Endpoint> LibUSB::InterfaceImpl::getEndpoint( uint8_t in
 
 	}
 
-	if (index > m_pInterface->altsetting[m_alternateSetting].bNumEndpoints)
-	{
-		throw std::logic_error("LibUSB::InterfaceImpl::getEndpoint() - index out of range.");
-	}
-
 
 	// Find the endpoint
-	EndpointContainer_t::iterator itEndpoint = m_EndpointContainer.find(index);
+	EndpointContainer_t::iterator itEndpoint = m_EndpointContainer.find(number);
 
 	std::shared_ptr<LibUSB::Endpoint> pEndpoint;
 
 	if (itEndpoint != m_EndpointContainer.end())
 	{
 
-		pEndpoint = m_EndpointContainer.find(index)->second;
+		pEndpoint = m_EndpointContainer.find(number)->second;
 
-		/// \note #1 Validate endpoint number against its index.
-		if (pEndpoint->Number() != index)
+		/// \note #1 Validate endpoint number against its number.
+		if (pEndpoint->Number() != number)
 		{
-			throw std::logic_error("LibUSB::InterfaceImpl::getEndpoint() - endpoint and index do not match as expected! (note #1)");
+			throw std::logic_error("LibUSB::InterfaceImpl::getEndpoint() - endpoint and number do not match as expected! (note #1)");
 		}
 
 	}
@@ -393,7 +429,7 @@ void LibUSB::InterfaceImpl::CreateEndpoints()
 	else
 	{
 
-		// I'm not positive that I want to disallow reusing already existing endpoints (ie, claim() the same interface
+		// I'm not positive that I want to disallow reusing already existing endpoints, i.e.: claim() the same interface
 
 	}
 

src/InterfaceImpl.hpp

@@ -87,8 +87,11 @@ namespace LibUSB
 		/// Returns the number of endpoints this interface/altsetting has.
 		uint8_t NumEndpoints()const;
 
+		/// Returns the number of a specified endpoint
+		uint8_t getEPNumberByIndex(uint8_t index)const;
+
 		/// Returns the specified endpoint
-		std::shared_ptr<Endpoint> getEndpoint(uint8_t index);
+		std::shared_ptr<Endpoint> getEndpoint(uint8_t number);
 
 	protected:
 
@@ -112,7 +115,7 @@ namespace LibUSB
 		/// Indicates that there has been through a successful Claim()
 		bool m_bClaimed;
 
-		/// Endpoint container type
+		/// Endpoint container type (number -> enpoint)
 		typedef std::map<uint8_t, std::shared_ptr<Endpoint>> EndpointContainer_t;
 
 		/// Endpoint container