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/* Universal Socket Modem Interface Library
* Copyright (c) 2013 Multi-Tech Systems
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#ifndef IPSTACK_H
#define IPSTACK_H

#include <string>

namespace mts {
    
/** This class is a pure virtual class that should be inherited from when implementing
* a communications device with an onboard IP stack.  Examples of this would be a Wi-Fi
* or Cellular radio with a built in IP stack. Typically the IP functionality in these
* devices is available through an AT or a similiar command interface. The inheriting
* class should map the device commands and functionality to the pure virtual methods provided
* here. There should also be at least one or more calls to setup the communication link
* specific paramters as an init method for example.  This would do things like configure
* the APN in a cellular radio or set the ssid for a WiFi device, which cannot be accounted
* for in an abstract class like this one.
*/
class IPStack
{
public:
    /// An enumeration for selecting the Socket Mode of TCP or UDP.
    enum Mode {
        TCP, UDP
    };

    /** This method is used to connect the IP layer and below for the interface. Required
    * configurations and settings should be done in other calls or an init function.
    *
    * @returns true if the connection was successfully established, otherwise false.
    */
    virtual bool connect() = 0;

    /** This method is used to disconnect the IP layer and below of the interface. This includes
    * any cleanup required before another connection can be made.
    */
    virtual void disconnect() = 0;

    /** This method is used to check if the IP layer of the interface is currently connected.
    *
    * @returns true if currently connected, otherwise false.
    */
    virtual bool isConnected() = 0;

    /** This method is used to set the local port for the UDP or TCP socket connection.
    * The connection can be made using the open method.
    *
    * @param port the local port of the socket as an int.
    */
    virtual bool bind(unsigned int port) = 0;

    /** This method is used to open a socket connection with the given parameters.
    * This socket connection is established using the devices built in IP stack.
    * Currently TCP is the only supported mode.
    *
    * @param address is the address you want to connect to in the form of xxx.xxx.xxx.xxx
    * or a URL. If using a URL make sure the device supports DNS and is properly configured
    * for that mode.
    * @param port the remote port you want to connect to.
    * @param mode an enum that specifies whether this socket connection is type TCP or UDP.
    * Currently only TCP is supported.
    * @returns true if the connection was successfully opened, otherwise false.
    */
    virtual bool open(const std::string& address, unsigned int port, Mode mode) = 0;

    /** This method is used to determine if a socket connection is currently open.
    *
    * @returns true if the socket is currently open, otherwise false.
    */
    virtual bool isOpen() = 0;

    /** This method is used to close a socket connection that is currently open.
    *
    * @returns true if successfully closed, otherwise returns false on an error.
    */
    virtual bool close() = 0;

    /** This method is used to read data off of a socket, assuming a valid socket
    * connection is already open.
    *
    * @param data a pointer to the data buffer that will be filled with the read data.
    * @param max the maximum number of bytes to attempt to read, typically the same as
    * the size of the passed in data buffer.
    * @param timeout the amount of time in milliseconds to wait in trying to read the max
    * number of bytes. If set to -1 the call blocks until it receives the max number of bytes
    * or encounters and error.
    * @returns the number of bytes read and stored in the passed in data buffer. Returns
    * -1 if there was an error in reading.
    */
    virtual int read(char* data, int max, int timeout = -1) = 0;

    /** This method is used to write data to a socket, assuming a valid socket
    * connection is already open.
    *
    * @param data a pointer to the data buffer that will be written to the socket.
    * @param length the size of the data buffer to be written.
    * @param timeout the amount of time in milliseconds to wait in trying to write the entire
    * number of bytes. If set to -1 the call blocks until it writes all of the bytes or 
    * encounters and error.
    * @returns the number of bytes written to the socket's write buffer. Returns
    * -1 if there was an error in writing.
    */
    virtual int write(const char* data, int length, int timeout = -1) = 0;


    /** This method is used to get the number of bytes available to read off the
    * socket.
    *
    * @returns the number of bytes available, 0 if there are no bytes to read.
    */
    virtual unsigned int readable() = 0;

    /** This method is used to get the space available to write bytes to the socket.
    *
    * @returns the number of bytes that can be written, 0 if unable to write.
    */
    virtual unsigned int writeable() = 0;

    /** This method is used to reset the device that provides the communications
    * capability. Note that you may have to wait some time after reset before the
    * device can be used.
    */
    virtual void reset() = 0;
};

}

#endif /* IPSTACK_H */