/*
    PIP - Platform Independent Primitives
    Packets extractor
    Copyright (C) 2013  Ivan Pelipenko peri4ko@gmail.com

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "pipacketextractor.h"


/** \class PIPacketExtractor
 * \brief Packets extractor
 * \details
 * \section PIPacketExtractor_sec0 Synopsis
 * This class implements packet recognition by header and custom validating
 * algorithm from data stream. Stream is formed from child %PIIODevice
 * passed from contructor or with function \a setDevice().
 * 
 * \section PIPacketExtractor_sec1 Principle of work
 * %PIPacketExtractor works with child %PIIODevice. \a read and \a write
 * functions directly call child device functions. You should start threaded
 * read of \b extractor to proper work. Extractor read data from child device,
 * form continuous buffer and analyze it.
 * 
 * \subsection PIPacketExtractor_sec1_0 Analysis
 * There is three parameters:
 * * header content
 * * header size
 * * payload size
 * 
 * Extractor can detect packet with compare your header with readed data.
 * It is default implementation of function \a packetHeaderValidate().
 * If header validating passed, function \a packetValidate() will be called.
 * If either of this function return \b false extractor shifts by one byte
 * and takes next header. If both functions returns \b true extractor shifts
 * by whole packet size.
 * \image html packet_detection.png
 * 
 * \subsection PIPacketExtractor_sec1_1 Variants
 * If header size = 0 and payload size = 0 there is no analysis will be done,
 * and function \a packetValidate() anyway will be called immediately after
 * successfully read from child device. \n
 * If header size = 0 but payload size != 0 extractor will be call function
 * \a packetValidate() each payload size bytes.
 * 
 * */


PIPacketExtractor::PIPacketExtractor(PIIODevice * device_, void * recHeaderPtr, int recHeaderSize, int recDataSize) {
	ret_func_header = 0;
	setPacketData(recHeaderPtr, recHeaderSize, recDataSize);
	setThreadedReadBufferSize(65536);
	setBufferSize(65536);
	setDevice(device_);
	allReaded = addSize = curInd = missed = 0;
}


void PIPacketExtractor::setDevice(PIIODevice * device_) {
	dev = device_;
	if (dev == 0) return;
}


bool PIPacketExtractor::threadedRead(uchar * readed, int size_) {
	memcpy(buffer.data(allReaded), readed, size_);
	allReaded += size_;
	while (allReaded >= packetSize + addSize && allReaded > 0) {
		if (headerSize > 0) {
			if (allReaded + curInd >= buffer_size) {
				memcpy(sbuffer.data(), buffer.data(), buffer_size);
				memcpy(buffer.data(), sbuffer.data(buffer_size - packetSize), allReaded);
				allReaded = packetSize;
				addSize = curInd = 0;
			}
			bool brk = false;
			while (!packetHeaderValidate((uchar * )headerPtr, buffer.data(curInd), headerSize)) {
				curInd++; missed++;
				if (packetSize > 0) missed_packets = missed / packetSize;
				if (curInd > addSize) {
					addSize += packetSize;
					brk = true;
					break;
				}
			}
			if (brk) continue;
			memcpy(mheader.data(), buffer.data(curInd), headerSize);
			if (headerPtr != 0) memcpy(headerPtr, buffer.data(curInd), headerSize);
			if (!packetValidate(buffer.data(curInd + headerSize), dataSize)) {
				curInd++; missed++;
				if (packetSize > 0) missed_packets = missed / packetSize;
				continue;
			}
			packetReceived(buffer.data(curInd), packetSize);
			memcpy(sbuffer.data(), buffer.data(), allReaded);
			memcpy(buffer.data(), sbuffer.data(packetSize + curInd), allReaded);
			allReaded -= packetSize + curInd;
			curInd = addSize = 0;
		} else {
			if (dataSize == 0) {
				if (packetValidate(buffer.data(), size_))
					packetReceived(buffer.data(), size_);
				memcpy(sbuffer.data(), buffer.data(), allReaded);
				memcpy(buffer.data(), sbuffer.data(size_), allReaded);
				allReaded -= size_;
			} else {
				if (packetValidate(buffer.data(), dataSize))
					packetReceived(buffer.data(), dataSize);
				memcpy(sbuffer.data(), buffer.data(), allReaded);
				memcpy(buffer.data(), sbuffer.data(packetSize), allReaded);
				allReaded -= packetSize;
			}
		}
	}
	return true;
}