NDEF NFC library

File content as of revision 11:eaf42739791e:

/**
 ******************************************************************************
 * @file    Type4NfcTag.h
 * @author  ST / Central Labs
 * @version V1.0.0
 * @date    1 Nov 2015
 * @brief   Generic interface that a device must implement for use the NDefLib
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; COPYRIGHT(c) 2015 STMicroelectronics</center></h2>
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *   1. Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *   2. Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *   3. Neither the name of STMicroelectronics nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ******************************************************************************
 */
 
#ifndef NDefNFCTAG_H_
#define NDefNFCTAG_H_

#include "NDefLib/Message.h"

namespace NDefLib {

/**
 * Abstract class used for write/read NDef message in an nfc tag
 */
class NDefNfcTag {
public:

	NDefNfcTag():mSessionIsOpen(false){}

	/**
	 * open the communication with the nfc tag
	 * \par when override this method call this implementation as last action for set the session opened
	 * @param force force to open a communication
	 * @return true if success
	 */
	virtual bool openSession(bool force = false){
		mSessionIsOpen=true;
		return true;
	}

	/**
	 * close the communication with the nfc tag
	 * \par when override this method call this implementation as last action for set the session closed
	 * @return true if success
	 */
	virtual bool closeSession(){
		mSessionIsOpen=false;
		return true;
	}

	/**
	 * write a message in the nfc tag, this call will delete the previous message
	 * @param msg message to write
	 * @return true if success
	 */
	bool write(const Message &msg) {
		if(!mSessionIsOpen)
			return false;

		const uint16_t length = msg.getByteLength();
		uint8_t *buffer = new uint8_t[length];
		if(buffer==NULL) //impossible allocate the buffer for write the message
			return false;
		msg.write(buffer);
		bool retValue = writeByte(buffer, length);
		delete[] buffer;
		return retValue;
	}

	/**
	 * read a message from the tag
	 * @param[in,out] msg message object where we will add the record read by the
	 * tag
	 * @return true if success
	 */
	bool read(Message *msg) {
		if(!mSessionIsOpen)
			return false;

		uint16_t length = getMessageLength();
		if (length == 0)
			return false;
		//else
		uint8_t *buffer = new uint8_t[length];
		if(buffer==NULL)
			return false;

		//read all the message content
		bool retValue = readByte(2, length, buffer);
		if (retValue) {
			Message::parseMessage(buffer, length, msg);
		}
		delete[] buffer;
		return retValue;
	}

	virtual ~NDefNfcTag() {}

	/**
	 * true if we have a communication open with the nfc tag
	 * @return
	 */
	bool isSessionOpen(){
		return mSessionIsOpen;
	}


protected:

	/**
	 * write a sequence of byte in the NDEF file
	 * @param buffer buffer to write
	 * @param length number of byte to write
	 * @param offset offset where start to write
	 * @return true if success
	 */
	virtual bool writeByte(const uint8_t *buffer, uint16_t length, uint16_t offset=0)=0;

	/**
	 * read a sequence of byte from the NDEF file
	 * @param byteOffset offset were start read
	 * @param byteLength number of byte to read
	 * @param[out] buffer buffer where store the data read
	 * @return true if success
	 */
	virtual bool readByte(const uint16_t byteOffset, const uint16_t byteLength,
			uint8_t *buffer)=0;

private:
	/**
	 * variable to set when we open/close a communication channel with the tag
	 */
	bool mSessionIsOpen;

	/**
	 * read the NDEF message length
	 * @return NDEF message length
	 */
	uint16_t getMessageLength() {
		uint8_t lenghtByte[2];
		if (readByte(0, 2, lenghtByte))
			return (((uint16_t) lenghtByte[0]) << 8 | lenghtByte[1]);
		return 0;
	} //getMessageLength

};

} /* namespace NDefLib */

#endif /* NDefNFCTAG_H_ */