Diff: ishtar.cpp

Revision:

0:086ea145b6d7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ishtar.cpp	Thu May 12 08:30:17 2011 +0000
@@ -0,0 +1,1601 @@
+/*
+	Ishtar Embedded
+	Copyright (C) 2008-2010:
+
+		Alexandre Habersaat <alexandre dot habersaat at gmail dot com>
+		Antoine Beyeler <abeyeler at ab-ware dot com>
+			(http://www.ab-ware.com)
+		Stephane Magnenat <stephane at magnenat dot net>
+			(http://stephane.magnenat.net)
+		
+	All rights reserved.
+
+	Ishtar Embedded is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	Ishtar Embedded 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 Lesser General Public License
+	along with Ishtar Embedded. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*!
+*	\file ishtar.c
+*	\brief Main file of the Ishtar Embedded server
+*
+*	\author Alexandre Habersaat, Antoine Beyeler
+*
+*	This file contains the core of the Ishtar Embedded server
+*/
+
+#include "ishtar.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Macro for FAR directive
+#if defined(__dsPIC33F__) || defined(__PIC24F__)
+	#define ISHTAR_ATTRIBUTE_FAR	__attribute__((far))
+#else
+	#define ISHTAR_ATTRIBUTE_FAR
+#endif
+
+
+//! The reception buffer of the server
+unsigned char ishtar_buffer[ISHTAR_BUFFER_SIZE] ISHTAR_ATTRIBUTE_FAR;
+
+// Statistics
+//! The number of overflows that occured in the reception buffer
+unsigned long ishtar_numberOfOverflows = 0;
+//! The number of bytes dropped in the state Header1
+unsigned long ishtar_numberOfDropHeader1 = 0;
+//! The number of bytes dropped in the state Header2
+unsigned long ishtar_numberOfDropHeader2 = 0;
+//! The number of bytes dropped in the state Header3
+unsigned long ishtar_numberOfDropHeader3 = 0;
+//! The number of bytes dropped in the state Header4
+unsigned long ishtar_numberOfDropHeader4 = 0;
+//! The number of messages dropped after a size checksum error
+unsigned long ishtar_numberOfDropSize = 0;
+//! The number of messages dropped after a content checksum error
+unsigned long ishtar_numberOfDropContent = 0;
+//! The total number of bytes received
+unsigned long ishtar_numberOfBytesReceived = 0;
+//! The total number of bytes sent
+unsigned long ishtar_numberOfBytesSent = 0;
+//! The total number of bytes read from memory
+unsigned long ishtar_numberOfBytesReadFromMemory = 0;
+//! The total number of bytes written to memory
+unsigned long ishtar_numberOfBytesWrittenToMemory = 0;
+//! The number of messages that were valid
+unsigned long ishtar_numberOfValidMessages = 0;
+//! The number of messages that were valid but contained invalid data (client error or wrong checksum validated)
+unsigned long ishtar_corruptedValidated = 0;
+//! The snapshot size
+unsigned long ishtar_snapshotSize = 0;
+//! If an error occured with the non-volatile memory
+unsigned char ishtar_memoryError = NO_ERROR;
+
+//! The number of services / variables registered
+ishtar_ServiceId ishtar_numberOfVariables = 0;
+//! The registry of the services / variables
+ishtar_ServiceDescription ishtar_services[ISHTAR_MAX_NUMBER_OF_SERVICES] ISHTAR_ATTRIBUTE_FAR;
+
+//! The Id of the active snapshot (or the last one if none is active)
+ishtar_RequestId ishtar_snapshotId = 0;
+//! Snapshot active
+unsigned char ishtar_snapshotActive = 0;
+
+
+// read buffer
+//! The start of the reception buffer
+unsigned char * ishtar_bufBegin;
+//! The end of the reception buffer
+unsigned char * ishtar_bufEnd;
+//! The position to write in the buffer for the next byte that is received
+unsigned char * ishtar_bufPos;
+
+//! The position of the next char to be consumed.
+unsigned char * ishtar_consumePos;
+//! Begining of the data payload of the current packet
+unsigned char* ishtar_dataStartMarker;
+//! The start of the first packet waiting to be treated in the buffer
+unsigned char * ishtar_packetBegin = 0;
+
+//! The state to read the first byte of message header
+#define ISHTAR_STATE_HEADER1 1
+//! The state to read the second byte of message header
+#define ISHTAR_STATE_HEADER2 2
+//! The state to read the third byte of message header
+#define ISHTAR_STATE_HEADER3 3
+//! The state to read the fourth byte of message header
+#define ISHTAR_STATE_HEADER4 4
+//! The state to read the size of message
+#define ISHTAR_STATE_SIZE 5
+//! The state to read the checksum of the size of the message
+#define ISHTAR_STATE_CHECKSUM_SIZE 6
+//! The state to read the content of the message
+#define ISHTAR_STATE_CONTENT 7
+//! The state to read the checksum of the content of the message
+#define ISHTAR_STATE_CHECKSUM_CONTENT 8
+
+//! The current state of the state machine for reception
+unsigned char ishtar_state = ISHTAR_STATE_HEADER1;
+//! Detects overflows in the reception buffer
+unsigned char ishtar_overFlow = 0;
+//! The current byte of the size being read
+unsigned char ishtar_sizeByteNum = 0;
+//! The current bypte of the checksum being read
+unsigned char ishtar_checksumByteNum = 0;
+
+// Checksum read
+//! The checksum read for the size
+unsigned short ishtar_sizeChecksumRead = 0;
+//! The ckecksum read for the content
+unsigned short ishtar_contentChecksumRead = 0;
+// Checksum calculated
+//! Temporary variables to calculate checksums
+unsigned char ishtar_ckA, ishtar_ckB;
+//! The total size of the current packet
+unsigned long ishtar_curPacketSize = 0;
+//! The number of bytes read for the current packet
+unsigned long ishtar_curSize = 0;
+
+//! At least one client is connected to the server
+unsigned char ishtar_connected = 0;
+
+// Non-volatile memory access
+//! The lowest memory address that Ishtar is allowed to read/write
+unsigned short ishtar_memoryMinAddress = 0;
+//! The highest memory address that Ishtar is allowed to read/write
+unsigned short ishtar_memoryMaxAddress = 0;
+//! The external function to read the non-volatile memory
+ishtar_MemoryReadFunc ishtar_memoryReadFunc = 0;
+//! The external function to write the non-volatile memory
+ishtar_MemoryWriteFunc ishtar_memoryWriteFunc = 0;
+//! The checksum A for the non-volatile memory consistency
+unsigned char ishtar_memoryChecksumA = 0;
+//! The checksum B for the non-volatile memory consistency
+unsigned char ishtar_memoryChecksumB = 0;
+
+// Send function
+//! The external function to call to send data through communication
+ishtar_ExternalSendFunc ishtar_externalSendFunc;
+//! The external function to call to send the first heavy messages (blocking function)
+ishtar_ExternalSendFunc ishtar_externalSendBlockingFunc;
+//! The current function that is used to send data (blocking or non-blocking)
+ishtar_ExternalSendFunc ishtar_currentSendFunc;
+//! The external function to flush the content of the external output buffer (if used)
+ishtar_ExternalFlushFunc ishtar_externalFlushFunc;
+
+//! The intermediate function to send data and calculate the checksum of the sent data
+void ishtar_SendData(unsigned char * data, unsigned long len);
+//! The function to send the message header
+void ishtar_SendHeader();
+//! The function to reset the checksums
+void ishtar_InitCk();
+//! The function to send the current checksum of the message
+void ishtar_SendCk();
+
+//! An empty function
+void ishtar_DoNothing() { }
+
+//! This function inits the pointers to the reception buffer
+void ishtar_InitBuffer();
+//! This function is used for debug, to register statistics variables into Ishtar
+void ishtar_RegisterDebugVars();
+
+// utils
+//! This function is used to calculate the checksum of a size
+unsigned short ishtar_CalculateSizeChecksum(unsigned long size);
+//! This function normalizes an address (usually old address + offset) to stay inside the reception buffer
+inline unsigned char * ishtar_WrapAddr(unsigned char * addr);
+//! This function increments the address of the reception buffer
+inline void ishtar_IncAddr(unsigned char ** addr, unsigned long size);
+
+//! This function reads the content of an address and copies it into a variable (target)
+inline void ishtar_At(unsigned char ** addr, unsigned char * target, unsigned char size);
+// This function reads the content of an address, copies it into a variable and increment the address to the next position
+inline void ishtar_AtInc(unsigned char ** addr, unsigned char * target, unsigned char size);
+
+//! This function sends a zero-terminated string
+void ishtar_SendString(const char * sz);
+//! This function sends the value of a variable
+void ishtar_SendValue(unsigned char * value, ishtar_ValueVectorType type, unsigned long index);
+//! This function reads a value in a buffer, write it into the registry and increments the read buffer
+void ishtar_SetValueInc(unsigned char * value, ishtar_ValueVectorType type, unsigned long index, unsigned char ** addr);
+
+//! This function returns the length of a zero-terminated string or ISHTAR_STRING_MAX_SIZE
+unsigned long ishtar_Strlen(const char * addr);
+//! This function returns the size of a type
+unsigned long ishtar_TypeSize(ishtar_ValueVectorType type);
+
+// treat messages
+//! This function decodes the type of a packet and call the corresponding dedicated function
+void ishtar_HandlePacket(unsigned char * addr, unsigned long len);
+//! This function decodes the content of a Hello packet and sends the answer
+void ishtar_HandleHelloCall(unsigned char * addr, unsigned long len);
+//! This function decodes the content of a GetServiceList packet and sends the answer
+void ishtar_HandleGetServiceListCall(unsigned char * addr, unsigned long len);
+//! This function decodes the content of a Get packet and sends the answer. It may also set up a snapshot.
+void ishtar_HandleGetCall(unsigned char * addr, unsigned long len);
+//! This function decodes the content of a Set packet and executes the modification on the local service registry
+void ishtar_HandleSetCall(unsigned char * addr, unsigned long len);
+//! This function decodes the content of a disconnection packet and stops the snapshot
+void ishtar_HandleByeByeCall(unsigned char * addr, unsigned long len);
+
+/*!
+*	This function normalizes an address (usually old address + offset) to stay inside the reception buffer
+*/
+inline unsigned char * ishtar_WrapAddr(unsigned char * addr)
+{
+	if (addr >= ishtar_bufEnd)
+	{
+		return (unsigned char*)((unsigned int)ishtar_bufBegin + (unsigned int)addr - (unsigned int)ishtar_bufEnd);
+	}
+	else
+	{
+		return addr;
+	}
+}
+
+/*!
+*	This function increments the address of the reception buffer
+*/
+inline void ishtar_IncAddr(unsigned char ** addr, unsigned long size)
+{
+	*addr += size;
+	*addr = ishtar_WrapAddr(*addr);
+}
+
+/*!
+*	This function reads the content of an address and copies it into a variable (target)
+*/
+inline void ishtar_At(unsigned char ** addr, unsigned char * target, unsigned char size)
+{
+	unsigned char i;
+
+	for (i = 0; i < size; ++i)
+	{
+		target[i] = *ishtar_WrapAddr(*addr + i);
+	}
+}
+
+/*!
+*	This function reads the content of an address, copies it into a variable and increment the address to the next position
+*/
+inline void ishtar_AtInc(unsigned char ** addr, unsigned char * target, unsigned char size)
+{
+	ishtar_At(addr, target, size);
+	ishtar_IncAddr(addr, size);
+}
+
+
+
+/*!
+*	This function sends a zero-terminated string
+*/
+void ishtar_SendString(const char * sz)
+{
+	// 4 name.type
+	ishtar_ValueVectorSize nameSize;
+	unsigned long j;
+
+	// 4 name.size
+	nameSize = ishtar_Strlen(sz);
+	ishtar_SendData((unsigned char*)(&nameSize), sizeof(ishtar_ValueVectorSize));
+	// X name
+	for (j = 0; j < nameSize; ++j)
+	{
+		ishtar_SendData((unsigned char*)&(sz[j]), 1);
+	}
+}
+
+/*!
+*	This function sends the value of an element of a local variable
+*
+*	@param value The pointer to the variable to read
+*	@param type The type of the variable
+*	@param index The index of the element to read
+*/
+void ishtar_SendValue(unsigned char * value, ishtar_ValueVectorType type, unsigned long index)
+{
+	unsigned long size;
+	unsigned char * val;
+
+	size = ishtar_TypeSize(type);
+	val = (unsigned char*) value;
+	ishtar_SendData(&val[size * index], size);
+}
+
+/*!
+*	This function modifies the value of one element of a local variable
+*
+*	@param value The pointer to the variable to set
+*	@param type The type of the variable to set
+*	@param index The index of the element to set (or 0 for a normal variable)
+*	@param addr The address from which to read the value to set
+*/
+void ishtar_SetValueInc(unsigned char * value, ishtar_ValueVectorType type, unsigned long index, unsigned char ** addr)
+{
+	unsigned long i;
+	unsigned long size;
+
+	size = ishtar_TypeSize(type);
+
+	for (i = 0; i < size; ++i)
+	{
+		value[size*index+i] = **addr;
+		*addr = ishtar_WrapAddr(*addr + 1);
+	}
+}
+
+/*!
+*	This function calculates the checksum of a 4-bytes size
+*
+*	@return The size on which the checksum is calculated
+*	@return The calculated checksum
+*/
+unsigned short ishtar_CalculateSizeChecksum(unsigned long size)
+{
+	unsigned char i;
+	unsigned char * p;
+	unsigned char ckA, ckB;
+
+	ckA = 0;
+	ckB = 0;
+	p = (unsigned char*)(&size);
+	for (i = 0; i < 4; ++i)
+	{
+		ckA += *(p + i);
+		ckB += ckA;
+	}
+
+	return (ckA << 8 | ckB);
+}
+
+/*!
+*	This function sends any data. The data sent are added to the current checksums
+*
+*	@param data A pointer to the data to send
+*	@param len The number of bytes to send from the pointer
+*/
+void ishtar_SendData(unsigned char * data, unsigned long len)
+{
+	// Add checksums
+	unsigned long i;
+	for (i = 0; i < len; ++i)
+	{
+		ishtar_ckA += data[i];
+		ishtar_ckB += ishtar_ckA;
+	}
+	// send data
+	ishtar_currentSendFunc(data, len);
+
+	ishtar_numberOfBytesSent += len;
+}
+
+/*!
+*	This function sends the Ishtar headers
+*/
+void ishtar_SendHeader()
+{
+	// unsigned long header;
+	unsigned char h1, h2, h3, h4;
+	h1 = ISHTAR_HEADER1;
+	h2 = ISHTAR_HEADER2;
+	h3 = ISHTAR_HEADER3;
+	h4 = ISHTAR_HEADER4;
+
+	//header = (ISHTAR_HEADER1) | (ISHTAR_HEADER2 << 8) | (ISHTAR_HEADER3 << 16) | (ISHTAR_HEADER4 << 24);
+	ishtar_currentSendFunc(&h1, 1);
+	ishtar_currentSendFunc(&h2, 1);
+	ishtar_currentSendFunc(&h3, 1);
+	ishtar_currentSendFunc(&h4, 1);
+}
+
+/*!
+*	This function resets the current checksum
+*/
+void ishtar_InitCk()
+{
+	// initialise checksums to 0
+	ishtar_ckA = 0;
+	ishtar_ckB = 0;
+}
+
+/*!
+*	This function sends the current checksum
+*/
+void ishtar_SendCk()
+{
+	// compile actual checksums
+	unsigned short checksum;
+	checksum = (ishtar_ckA << 8) | ishtar_ckB;
+
+	// send the compiled checksum
+	ishtar_currentSendFunc((unsigned char*)(&checksum), 2);
+}
+
+/*!
+*	This function is provided for convenience if multiple bytes are received at once.
+*	It will call ishtar_ReceiveDataByte() for each of these data bytes
+*/
+void ishtar_ReceiveData(unsigned char * data, unsigned long len)
+{
+	unsigned long i;
+	for (i = 0; i < len; ++i)
+	{
+		ishtar_ReceiveDataByte(data[i]);
+	}
+}
+
+/*!
+*	This function buffers all incoming bytes without processing them. It drop
+*	any byte in case of buffer overflow. 
+*/
+void ishtar_ReceiveDataByte(unsigned char c)
+{
+	++ishtar_numberOfBytesReceived;
+	
+	unsigned char* nextAddr = ishtar_WrapAddr(ishtar_bufPos + 1);
+	if (nextAddr == ishtar_packetBegin)
+	{
+		// we have an overflow
+		ishtar_overFlow = 1;
+		ishtar_numberOfOverflows++;
+	}
+	else
+	{
+		*ishtar_bufPos = c;
+		ishtar_bufPos = nextAddr;
+	}
+}
+
+
+/*!
+*	This function process bytes from the buffer with a state machine. When a packet
+*	is completed, it calls #ishtar_HandlePacket().
+*
+*	@param addr The address of the byte to process.
+*/
+void ishtar_ConsumeBufferedByte(unsigned char* addr)
+{
+	unsigned char * p;
+	unsigned long i;
+	unsigned char ckA, ckB;
+	
+	unsigned char c = *addr;
+	
+
+	if (ishtar_state == ISHTAR_STATE_CONTENT)
+	{
+		if (ishtar_curSize == 0)
+			ishtar_dataStartMarker = addr;
+			
+		// Increase size
+		++ishtar_curSize;
+
+		// end of packet
+		if (ishtar_curSize == ishtar_curPacketSize)
+		{
+			ishtar_contentChecksumRead = 0;
+			ishtar_checksumByteNum = 0;
+			ishtar_state = ISHTAR_STATE_CHECKSUM_CONTENT;
+		}
+	}
+	else if (ishtar_state == ISHTAR_STATE_SIZE)
+	{
+		p = (unsigned char*)(&ishtar_curPacketSize);
+		*( p + ishtar_sizeByteNum++ ) = c;
+		
+		if (ishtar_sizeByteNum == ISHTAR_NUMBER_OF_SIZE_BYTES)
+		{
+			ishtar_sizeChecksumRead = 0;
+			ishtar_checksumByteNum = 0;
+			ishtar_state = ISHTAR_STATE_CHECKSUM_SIZE;
+		}
+	}
+	else if (ishtar_state == ISHTAR_STATE_HEADER1)
+	{
+		if (c == ISHTAR_HEADER1)
+			ishtar_state = ISHTAR_STATE_HEADER2;
+		else
+			++ishtar_numberOfDropHeader1;
+	}
+	else if (ishtar_state == ISHTAR_STATE_CHECKSUM_SIZE)
+	{
+		p = (unsigned char*)(&ishtar_sizeChecksumRead);
+		*(p + ishtar_checksumByteNum++) = c;
+
+		if (ishtar_checksumByteNum == ISHTAR_NUMBER_OF_CHECKSUM_BYTES)
+		{
+			p = (unsigned char*)(&ishtar_curPacketSize);
+
+			// calculate checksum of size
+			ckA = 0;
+			ckB = 0;
+			for (i = 0; i < ISHTAR_NUMBER_OF_SIZE_BYTES; ++i)
+			{
+				ckA += (ishtar_curPacketSize >> (8 * i)) & 0xFF;
+				ckB += ckA;
+			}
+
+			if (ishtar_sizeChecksumRead == (ckA << 8 | ckB))
+			{
+				ishtar_curSize = 0;
+				ishtar_state = ISHTAR_STATE_CONTENT;
+			}
+			else
+			{
+				++ishtar_numberOfDropSize;
+				ishtar_state = ISHTAR_STATE_HEADER1;
+			}
+		}
+	}
+	else if (ishtar_state == ISHTAR_STATE_CHECKSUM_CONTENT)
+	{
+		p = (unsigned char*)(&ishtar_contentChecksumRead);
+		*(p + ishtar_checksumByteNum++) = c;
+
+		if (ishtar_checksumByteNum == ISHTAR_NUMBER_OF_CHECKSUM_BYTES)
+		{
+			// calculate checksum of content, start after the size
+			ckA = 0;
+			ckB = 0;
+			for (i = 0; i < ishtar_curPacketSize; ++i)
+			{
+				ckA += *(ishtar_WrapAddr(ishtar_dataStartMarker + i));
+				ckB += ckA;
+			}
+
+			// checksum correct
+			if (ishtar_contentChecksumRead == (ckA << 8 | ckB))
+			{
+				// handle the packet
+				ishtar_HandlePacket(ishtar_dataStartMarker, ishtar_curPacketSize);				
+				++ishtar_numberOfValidMessages;
+			}
+			else
+				++ishtar_numberOfDropContent;
+			
+			// the begining of the buffer is at the next char in all cases.
+			ishtar_packetBegin = ishtar_WrapAddr(addr + 1);
+
+			// go back for next message
+			ishtar_state = ISHTAR_STATE_HEADER1;
+		}
+	}
+	else if (ishtar_state == ISHTAR_STATE_HEADER2)
+	{
+		if (c == ISHTAR_HEADER2)
+			ishtar_state = ISHTAR_STATE_HEADER3;
+		else if (c == ISHTAR_STATE_HEADER1)
+		{
+			ishtar_state = ISHTAR_STATE_HEADER2;
+			++ishtar_numberOfDropHeader2;
+		}
+		else
+		{
+			ishtar_state = ISHTAR_STATE_HEADER1;
+			++ishtar_numberOfDropHeader2;
+		}
+	}
+	else if (ishtar_state == ISHTAR_STATE_HEADER3)
+	{
+		if (c == ISHTAR_HEADER3)
+			ishtar_state = ISHTAR_STATE_HEADER4;
+		else if (c == ISHTAR_STATE_HEADER1)
+		{
+			ishtar_state = ISHTAR_STATE_HEADER2;
+			++ishtar_numberOfDropHeader3;
+		}
+		else
+		{
+			ishtar_state = ISHTAR_STATE_HEADER1;
+			++ishtar_numberOfDropHeader3;
+		}
+	}
+	else if (ishtar_state == ISHTAR_STATE_HEADER4)
+	{
+		if (c == ISHTAR_HEADER4)
+		{
+			ishtar_state = ISHTAR_STATE_SIZE;
+			ishtar_curPacketSize = 0;
+			ishtar_sizeByteNum = 0;
+		}
+		else if (c == ISHTAR_STATE_HEADER1)
+		{
+			ishtar_state = ISHTAR_STATE_HEADER2;
+			++ishtar_numberOfDropHeader4;
+		}
+		else
+		{
+			ishtar_state = ISHTAR_STATE_HEADER1;
+			++ishtar_numberOfDropHeader4;
+		}
+	}
+	else
+		ishtar_state = ISHTAR_STATE_HEADER1;
+}
+
+// step
+
+/*!
+*	This function checks if there are some packets to treat in the input buffer
+*	If yes, it calls the decoding functions which send the answers to these packets.
+*/
+void ishtar_Step()
+{
+	// atomically read the curent bufPos
+	unsigned char* bufPos = ishtar_bufPos;
+	
+	while (ishtar_consumePos != bufPos)
+	{
+		ishtar_ConsumeBufferedByte(ishtar_consumePos);
+		ishtar_consumePos = ishtar_WrapAddr(ishtar_consumePos + 1);
+	}
+}
+
+/*!
+*	This function reads the start of a packet and determines it type.
+*	It then calls the corresponding dedicated function to decode the packet.
+*/
+void ishtar_HandlePacket(unsigned char * addr, unsigned long len)
+{
+	ishtar_MessageId type;
+
+	ishtar_AtInc(&addr, (unsigned char*)&type, sizeof(ishtar_MessageId));
+
+	switch (type)
+	{
+		case HELLO:
+		{
+			ishtar_HandleHelloCall(addr, len - sizeof(ishtar_MessageId));
+			break;
+		}
+		case GET_SERVICE_LIST:
+		{
+			ishtar_HandleGetServiceListCall(addr, len - sizeof(ishtar_MessageId));
+			break;
+		}
+		case GET_VALUES:
+		{
+			ishtar_HandleGetCall(addr, len - sizeof(ishtar_MessageId));
+			break;
+		}
+		case SET_VALUES:
+		{
+			ishtar_HandleSetCall(addr, len - sizeof(ishtar_MessageId));
+			break;
+		}
+		case BYE_BYE:
+		{
+			ishtar_HandleByeByeCall(addr, len - sizeof(ishtar_MessageId));
+			break;
+		}
+		default:
+		{
+			return;
+		}
+	}
+}
+
+/*!
+*	This function decodes the Hello calls and sends the Hello answer
+*/
+void ishtar_HandleHelloCall(unsigned char * addr, unsigned long len)
+{
+
+	// Stop snapshot when hello received
+	ishtar_snapshotActive = 0;
+
+	ishtar_NodeType nodeType;
+	ishtar_VersionType version;
+
+	ishtar_MessageId hello = HELLO;
+	ishtar_ProtocolType protocol;
+
+	unsigned long answerSize;
+	unsigned short sizeChecksum;
+
+	// READ
+	ishtar_AtInc(&addr, (unsigned char*)&nodeType, sizeof(ishtar_NodeType));
+	ishtar_AtInc(&addr, (unsigned char*)&version, sizeof(ishtar_VersionType));
+
+	// CALCULATE
+	if (version == ISHTAR_PROTOCOL_VERSION)
+		protocol = EMBEDDED;
+	else
+		protocol = INCOMPATIBLE;
+
+	// SEND
+	answerSize = sizeof(ishtar_MessageId) + sizeof(ishtar_ProtocolType);
+	sizeChecksum = ishtar_CalculateSizeChecksum(answerSize);
+
+	ishtar_currentSendFunc = ishtar_externalSendBlockingFunc;
+	ishtar_SendHeader();
+	// send size and size checksum
+	ishtar_SendData((unsigned char*)(&answerSize), sizeof(unsigned long));
+	ishtar_SendData((unsigned char*)(&sizeChecksum), sizeof(unsigned short));
+	// send content
+	ishtar_InitCk();
+	ishtar_SendData((unsigned char*)(&hello), sizeof(ishtar_MessageId));
+	ishtar_SendData((unsigned char*)(&protocol), sizeof(ishtar_ProtocolType));
+	ishtar_SendCk();
+
+	ishtar_externalFlushFunc();
+	ishtar_currentSendFunc = ishtar_externalSendFunc;
+
+	ishtar_connected = 1;
+}
+
+/*!
+*	This function decodes the ServiceList calls and sends the list of all registered variables
+*/
+void ishtar_HandleGetServiceListCall(unsigned char * addr, unsigned long len)
+{
+	// Nothing to read
+	// Calculate size
+	unsigned long answerSize; // AnswerType + numberOfVariables
+	ishtar_ServiceId i;
+
+	ishtar_MessageId serviceList;
+	unsigned short sizeChecksum;
+
+	// READ - nothing
+
+	// SEND
+	answerSize = sizeof(ishtar_MessageId) + sizeof(ishtar_ServiceId);
+	serviceList = SERVICE_LIST;
+	// ID (4) + name.size(4) + name(X) + type(4) + flags(4) + length(4)
+	// Must be in a for loop as the name of services have different sizes
+	for (i = 0; i < ishtar_numberOfVariables; ++i)
+	{
+		answerSize += sizeof(ishtar_ServiceId) + sizeof(ishtar_ValueVectorSize) + ishtar_Strlen(ishtar_services[i].name) + sizeof(ishtar_ValueVectorType) + sizeof(ishtar_ServiceFlags) + sizeof(ishtar_ValueVectorSize);
+	}
+
+	// calculate size checksum
+	sizeChecksum = ishtar_CalculateSizeChecksum(answerSize);
+
+	ishtar_currentSendFunc = ishtar_externalSendBlockingFunc;
+	ishtar_SendHeader();
+	// send size and size checksum
+	ishtar_SendData((unsigned char*)(&answerSize), sizeof(unsigned long));
+	ishtar_SendData((unsigned char*)(&sizeChecksum), sizeof(unsigned short));
+
+	// send content
+	ishtar_InitCk();
+	ishtar_SendData((unsigned char*)(&serviceList), sizeof(ishtar_MessageId));
+	ishtar_SendData((unsigned char*)(&ishtar_numberOfVariables), sizeof(ishtar_ServiceId));
+
+	// fill table
+	for (i = 0; i < ishtar_numberOfVariables; ++i)
+	{
+		// 4 service id
+		ishtar_SendData((unsigned char*)(&i), sizeof(ishtar_ServiceId));
+		// name.size(4) + name(X)
+		ishtar_SendString(ishtar_services[i].name);
+		// 4 service.type
+		ishtar_SendData((unsigned char*)(&(ishtar_services[i].type)), sizeof(ishtar_ValueVectorType));
+		// 4 service.flags
+		ishtar_SendData((unsigned char*)(&(ishtar_services[i].flags)), sizeof(ishtar_ServiceFlags));
+		// 4 service.length
+		ishtar_SendData((unsigned char*)(&(ishtar_services[i].length)), sizeof(ishtar_ValueVectorSize));
+	}
+
+	ishtar_SendCk();
+
+	ishtar_externalFlushFunc();
+	ishtar_currentSendFunc = ishtar_externalSendFunc;
+}
+
+/*!
+*	This function decodes the Get calls and sends the values for the requested data
+*/
+void ishtar_HandleGetCall(unsigned char * addr, unsigned long len)
+{
+	// Read
+	ishtar_RequestId requestID;
+	ishtar_ServiceId numberOfIds;
+	ishtar_ValueVectorSize numberOfIndices;
+
+
+	unsigned long answerSize;// VALUES(4) + requestID(4) + size(4)
+	unsigned short sizeChecksum;
+	ishtar_ServiceId i;
+	ishtar_ValueVectorSize j;
+
+	ishtar_ServiceId id;
+	ishtar_ValueVectorSize indice;
+	ishtar_ValueVectorSize length;
+	unsigned char snapshot = 0;
+	ishtar_MessageId values;
+	unsigned char * ids;
+
+	// READ
+	ishtar_AtInc(&addr,(unsigned char*)&requestID, sizeof(ishtar_RequestId));
+	ishtar_AtInc(&addr,(unsigned char*)&snapshot, sizeof(unsigned char));
+	ishtar_AtInc(&addr,(unsigned char*)&numberOfIds, sizeof(ishtar_ServiceId));
+
+	if (snapshot)
+	{
+		// saves the snapshot id
+		ishtar_snapshotId = requestID;
+		// snapshot canceled
+		if (numberOfIds == 0)
+		{
+			ishtar_snapshotActive = 0;
+		}
+		// new snapshot asked
+		else
+		{
+			ishtar_snapshotActive = 1;
+		}
+
+		// clear old snapshot
+		for (i = 0; i < ishtar_numberOfVariables; ++i)
+		{
+			ishtar_services[i].inSnapshot = 0;
+		}
+	}
+
+	ids = addr;
+
+	// Size
+	answerSize = sizeof(ishtar_MessageId) + sizeof(ishtar_RequestId);
+
+	values = VALUES;
+
+	for (i = 0; i<numberOfIds; ++i)
+	{
+		// read id of service
+		ishtar_AtInc(&addr,(unsigned char*)&id, sizeof(ishtar_ServiceId));
+
+		// Problem, a corrupted message has been validated
+		if ( id >= ishtar_numberOfVariables)
+		{
+			++ishtar_corruptedValidated;
+			return;
+		}
+
+		// if the variable is in the snapshot
+		if (snapshot)
+		{
+			ishtar_services[id].inSnapshot = 1;
+		}
+
+		// Read the number of indices
+		ishtar_AtInc(&addr,(unsigned char*)&numberOfIndices, sizeof(ishtar_ValueVectorSize));
+		// Eat these indices, so that the next variable id is correct
+		for (j = 0; j < numberOfIndices; ++j)
+		{
+			ishtar_AtInc(&addr,(unsigned char*)&indice, sizeof(ishtar_ValueVectorSize));
+			// Problem, a corrupter message has been validated
+			if (indice > ishtar_services[id].length)
+			{
+				++ishtar_corruptedValidated;
+				return;
+			}
+		}
+
+		// if the size is 0, it means variable size, so we must specify it.
+		if (ishtar_services[id].length == 0 && ishtar_services[id].type == UCHAR)
+		{
+			answerSize += sizeof(ishtar_ValueVectorSize);// size of the size
+			answerSize += ishtar_Strlen((char*)(ishtar_services[id].value)); // size of the data
+		}
+		else
+		{
+			// we only put the data in the next message
+			// here the full variable
+			if (numberOfIndices == 0)
+			{
+				answerSize += ((unsigned long)(ishtar_services[id].length)) * ishtar_TypeSize(ishtar_services[id].type);
+			}
+			// here only some values
+			else
+			{
+				answerSize += ((unsigned long)(numberOfIndices)) * ishtar_TypeSize(ishtar_services[id].type);
+			}
+		}
+	}
+
+	// answer only if non-snapshot, otherwise it will be done in ishtar_Snapshot()
+	if (!snapshot)
+	{
+		sizeChecksum = ishtar_CalculateSizeChecksum(answerSize);
+
+		// SEND
+		ishtar_SendHeader();
+		// send size and size checksum
+		ishtar_SendData((unsigned char*)(&answerSize), 4);
+		ishtar_SendData((unsigned char*)(&sizeChecksum), 2);
+
+		// send content
+		ishtar_InitCk();
+		ishtar_SendData((unsigned char*)(&values), sizeof(ishtar_MessageId));
+		ishtar_SendData((unsigned char*)(&requestID), sizeof(ishtar_RequestId));
+
+		for (i = 0; i < numberOfIds; ++i)
+		{
+			// service id
+			ishtar_AtInc(&ids, (unsigned char*)&id, sizeof(ishtar_ServiceId));
+			// number of indices
+			ishtar_AtInc(&ids,(unsigned char*)&numberOfIndices, sizeof(ishtar_ValueVectorSize));
+
+			// length == 0 mean variable size, ONLY for char or UCHAR, with ended caracter equal to '\0'
+			if (ishtar_services[id].type == UCHAR && ishtar_services[id].length == 0)
+			{
+				length = ishtar_Strlen((char*)(ishtar_services[id].value));
+				ishtar_SendData((unsigned char*)(&length), sizeof(ishtar_ValueVectorSize));
+
+				for (j = 0; j < length; ++j)
+				{
+					ishtar_SendValue((unsigned char*)ishtar_services[id].value, ishtar_services[id].type, j);
+				}
+
+			}
+			else
+			{
+				// read the indices
+				if (numberOfIndices > 0)
+				{
+					for (j = 0; j < numberOfIndices; ++j)
+					{
+						ishtar_AtInc(&ids,(unsigned char*)&indice, sizeof(ishtar_ValueVectorSize));
+						ishtar_SendValue((unsigned char*)ishtar_services[id].value, ishtar_services[id].type, indice);
+
+					}
+				}
+				else
+				{
+					for (j = 0; j < ishtar_services[id].length; ++j)
+					{
+
+						ishtar_SendValue((unsigned char*)ishtar_services[id].value, ishtar_services[id].type, j);
+					}
+				}
+			}
+		}
+
+		ishtar_SendCk();
+		ishtar_externalFlushFunc();
+	}
+}
+
+/*!
+*	This function decodes the Set calls and updates local variables
+*/
+void ishtar_HandleSetCall(unsigned char * addr, unsigned long len)
+{
+	ishtar_RequestId requestID;
+	unsigned char feedback;
+	ishtar_ServiceId numberOfIds;
+	ishtar_ValueVectorSize numberOfIndices;
+	ishtar_ServiceId i;
+	ishtar_ValueVectorSize j;
+	ishtar_ServiceId id;
+	ishtar_ValueVectorSize indice;
+	unsigned char * indicesAddr;
+	
+	unsigned long answerSize;
+	unsigned short sizeChecksum;
+	ishtar_MessageId setAck;
+
+
+	// READ
+	// request id
+	ishtar_AtInc(&addr, (unsigned char*)&requestID, sizeof(ishtar_RequestId));
+	// feedback
+	ishtar_AtInc(&addr, (unsigned char*)&feedback, 1);
+	//numberOfIds
+	ishtar_AtInc(&addr, (unsigned char*)&numberOfIds, sizeof(ishtar_ServiceId));
+
+	for (i = 0; i < numberOfIds; ++i)
+	{
+		//id = ishtar_ulongAtInc(&addr);
+		ishtar_AtInc(&addr, (unsigned char*)&id, sizeof(ishtar_ServiceId));
+
+		// Problem, a corrupted message has been validated
+		if (id > ishtar_numberOfVariables)
+		{
+			++ishtar_corruptedValidated;
+			return;
+		}
+
+		// number of indices
+		ishtar_AtInc(&addr, (unsigned char*)&numberOfIndices, sizeof(ishtar_ValueVectorSize));
+		indicesAddr = addr;
+
+		// readonly, so skip
+		if (ishtar_services[id].flags & READ_ONLY)
+		{
+			if (numberOfIndices == 0)
+			{
+				// skip
+				ishtar_IncAddr(&addr, ishtar_TypeSize(ishtar_services[id].type) * ((unsigned long)(ishtar_services[id].length)));// values
+			}
+			else
+			{
+				// skip
+				ishtar_IncAddr(&addr, numberOfIndices * sizeof(ishtar_ValueVectorSize));// indices
+				ishtar_IncAddr(&addr, ishtar_TypeSize(ishtar_services[id].type) * numberOfIndices);// values
+			}
+		}
+		else
+		{
+			if (numberOfIndices == 0)
+			{
+				for (j = 0; j < ishtar_services[id].length; ++j)
+					ishtar_SetValueInc((unsigned char*)ishtar_services[id].value,ishtar_services[id].type, j, &addr);
+			}
+			else
+			{
+				ishtar_IncAddr(&addr, numberOfIndices * sizeof(ishtar_ValueVectorSize));
+
+				// now addr points to the first value, indicesAddr to the first index
+
+				for (j = 0; j < numberOfIndices; ++j)
+				{
+					ishtar_AtInc(&indicesAddr, (unsigned char*)&indice, sizeof(ishtar_ValueVectorSize));
+					// Problem, a corrupted message has been validated
+					if (indice > ishtar_services[id].length)
+					{
+						++ishtar_corruptedValidated;
+						return;
+					}
+					
+					ishtar_SetValueInc((unsigned char*)ishtar_services[id].value, ishtar_services[id].type, (unsigned long)indice, &addr);
+				}
+			}
+			
+			// call feedback function if existing
+			if (ishtar_services[id].feedbackFunc)
+				ishtar_services[id].feedbackFunc(&ishtar_services[id]);
+		}
+	}
+	// SEND - the ack if feedback enabled
+	if (feedback)
+	{
+		setAck = SET_ACK;
+		answerSize = sizeof(ishtar_MessageId) + sizeof(ishtar_RequestId);
+		sizeChecksum = ishtar_CalculateSizeChecksum(answerSize);
+
+		ishtar_SendHeader();
+		// send size and size checksum
+		ishtar_SendData((unsigned char*)(&answerSize), 4);
+		ishtar_SendData((unsigned char*)(&sizeChecksum), 2);
+
+		// send content
+		ishtar_InitCk();
+		ishtar_SendData((unsigned char*)(&setAck), sizeof(ishtar_MessageId));
+		ishtar_SendData((unsigned char*)(&requestID), sizeof(ishtar_RequestId));
+		ishtar_SendCk();
+
+		ishtar_externalFlushFunc();
+	}
+}
+
+/*!
+*	This function decodes the content of a disconnection packet and stops the snapshot.
+*/
+void ishtar_HandleByeByeCall(unsigned char * addr, unsigned long len)
+{
+	ishtar_snapshotActive = 0;
+	ishtar_connected = 0;
+}
+
+/*!
+*	This function first checks if there is an active snapshot.
+*	If yes, it sends the data for this snapshot.
+*/
+void ishtar_Snapshot()
+{
+	if (ishtar_snapshotActive && ishtar_connected)
+	{
+		ishtar_RequestId requestID;
+
+		unsigned long answerSize;// VALUES(4) + requestID(4) + size(4)
+		unsigned short sizeChecksum;
+		ishtar_ServiceId i;
+		ishtar_ValueVectorSize j;
+		ishtar_ValueVectorSize length;
+
+		ishtar_MessageId values;
+
+		answerSize = sizeof(ishtar_MessageId) + sizeof(ishtar_RequestId);
+
+		values = VALUES;
+		requestID = ishtar_snapshotId;
+
+		// CALCULATE SIZE
+		for (i = 0; i < ishtar_numberOfVariables; ++i)
+		{
+			// if the variable is in the snapshot
+			if (ishtar_services[i].inSnapshot == 1)
+			{
+				// if the size is 0, it mean variable, so we must specify it.
+				if (ishtar_services[i].length == 0)
+				{
+					answerSize += sizeof(ishtar_ValueVectorSize);
+					answerSize += ishtar_Strlen((char*)(ishtar_services[i].value));
+				}
+				else
+				{
+					// in snapshots, the full variable is sent, cannot save indices in embedded version
+					answerSize += ((unsigned long)(ishtar_services[i].length)) * ishtar_TypeSize(ishtar_services[i].type);
+				}
+			}
+		}
+
+		ishtar_snapshotSize = answerSize;
+		sizeChecksum = ishtar_CalculateSizeChecksum(answerSize);
+
+		// SEND
+		ishtar_SendHeader();
+		// send size and size checksum
+		ishtar_SendData((unsigned char*)(&answerSize), 4);
+		ishtar_SendData((unsigned char*)(&sizeChecksum), 2);
+
+		// send content
+		ishtar_InitCk();
+		ishtar_SendData((unsigned char*)(&values), sizeof(ishtar_MessageId));
+		ishtar_SendData((unsigned char*)(&requestID), sizeof(ishtar_RequestId));
+
+		for (i = 0; i < ishtar_numberOfVariables; ++i)
+		{
+			if (ishtar_services[i].inSnapshot == 1)
+			{
+				// service id
+				// length == 0 mean variable size, ONLY for char or UCHAR, with ended caracter equal to '\0'
+				if (ishtar_services[i].length == 0 && ishtar_services[i].type == UCHAR)
+				{
+					length = ishtar_Strlen((char*)(ishtar_services[i].value));
+					ishtar_SendData((unsigned char*)(&length), sizeof(ishtar_ValueVectorSize));
+
+					for (j = 0; j < length; ++j)
+					{
+						ishtar_SendValue((unsigned char*)ishtar_services[i].value, ishtar_services[i].type, j);
+					}
+
+				}
+				else
+				{
+					length = ishtar_services[i].length;
+					for (j=0; j < length; ++j)
+					{
+						ishtar_SendValue((unsigned char*)ishtar_services[i].value, ishtar_services[i].type, j);
+					}
+				}
+			}
+		}
+
+		ishtar_SendCk();
+
+		ishtar_externalFlushFunc();
+	}
+}
+
+
+/*!
+*	This function reads the values from the memory and assign them to the Ishtar variables.
+*
+*	It first read the checksum in the 2 first bytes and checks if it is correct, then it reads and assigns the value.
+*	The checksum is used to invalidate memory data when the variable list is changed.
+*/
+void ishtar_LoadFromMemory()
+{
+	unsigned short i;
+	unsigned short j;
+	unsigned short size;
+	unsigned short nameSize;
+	unsigned short addr = ishtar_memoryMinAddress;
+	unsigned char readChecksumA, readChecksumB;
+
+	if (!ishtar_memoryReadFunc)
+	{
+		ishtar_memoryError = READ_FUNC_NULL;
+		return;
+	}
+
+	// read checksum first
+	if (ishtar_memoryReadFunc(addr++, &readChecksumA, 1) != 1)
+	{
+		ishtar_memoryError = READ_ERROR;
+		return;
+	}
+	ishtar_numberOfBytesReadFromMemory += 1;
+	if (ishtar_memoryReadFunc(addr++, &readChecksumB, 1) != 1)
+	{
+		ishtar_memoryError = READ_ERROR;
+		return;
+	}
+	ishtar_numberOfBytesReadFromMemory += 1;
+
+	// verify checksums
+	ishtar_memoryChecksumA = 0;
+	ishtar_memoryChecksumB = 0;
+
+	for (i = 0; i < ishtar_numberOfVariables; ++i)
+	{
+		if (ishtar_services[i].flags & PERSISTENT)
+		{
+			// the id, type, length and name are used in the checksum
+			ishtar_memoryChecksumA += (unsigned char)ishtar_services[i].type;
+			ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+			ishtar_memoryChecksumA += (unsigned char)ishtar_services[i].length;
+			ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+			ishtar_memoryChecksumA += (unsigned char)i;
+			ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+
+			nameSize = ishtar_Strlen(ishtar_services[i].name);
+			for (j = 0; j < nameSize; ++j)
+			{
+				// checksum the name
+				ishtar_memoryChecksumA += (unsigned char)ishtar_services[i].name[j];
+				ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+			}
+		}
+	}
+	
+	// checksum is wrong
+	if (!(readChecksumA == ishtar_memoryChecksumA && readChecksumB == ishtar_memoryChecksumB))
+	{
+		ishtar_memoryError = CHECKSUM_WRONG;
+		return;
+	}
+
+	// assign the values
+	for (i = 0; i < ishtar_numberOfVariables; ++i)
+	{
+		if (ishtar_services[i].flags & PERSISTENT)
+		{
+			// size of this variable in the memory
+			size = (unsigned short)(ishtar_TypeSize(ishtar_services[i].type) * ishtar_services[i].length);
+			// write value to memory
+			if (size != ishtar_memoryReadFunc(addr, ishtar_services[i].value, size))
+			{
+				ishtar_memoryError = READ_ERROR;
+				return;
+			}	
+			addr += size;
+			ishtar_numberOfBytesReadFromMemory += size;
+			
+			// call feedback function if existing
+			if (ishtar_services[i].feedbackFunc)
+				ishtar_services[i].feedbackFunc(&ishtar_services[i]);
+		}
+	}
+
+	ishtar_memoryError = 0;
+}
+
+/*!
+*	This function writes the values of the Ishtar variables to the memory.
+*
+*	It first checks that the is enough space in the memory, then it writes the checksum in the first 2 bytes, and then the values.
+*/
+void ishtar_SaveToMemory()
+{
+	unsigned short i;
+	unsigned short j;
+	unsigned short size = 2;
+	unsigned short nameSize;
+	unsigned short addr = ishtar_memoryMinAddress + 2;
+
+	if (!ishtar_memoryWriteFunc)
+	{
+		ishtar_memoryError = WRITE_FUNC_NULL;
+		return;
+	}
+
+	// check size
+	for (i = 0; i < ishtar_numberOfVariables; ++i)
+	{
+		if (ishtar_services[i].flags & PERSISTENT)
+		{
+			size += ishtar_TypeSize(ishtar_services[i].type) * ishtar_services[i].length;
+		}
+	}
+
+	// checks if there is enough memory available
+	if (ishtar_memoryMaxAddress - ishtar_memoryMinAddress < size)
+	{
+		ishtar_memoryError = NOT_ENOUGH_SPACE;
+		return;
+	}
+
+
+	// write and calculate checksum
+	ishtar_memoryChecksumA = 0;
+	ishtar_memoryChecksumB = 0;
+
+	for (i = 0; i < ishtar_numberOfVariables; ++i)
+	{
+		if (ishtar_services[i].flags & PERSISTENT)
+		{
+			// the id, type, length and name are used in the checksum
+			ishtar_memoryChecksumA += (unsigned char)ishtar_services[i].type;
+			ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+			ishtar_memoryChecksumA += (unsigned char)ishtar_services[i].length;
+			ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+			ishtar_memoryChecksumA += (unsigned char)i;
+			ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+
+			nameSize = ishtar_Strlen(ishtar_services[i].name);
+			for (j = 0; j < nameSize; ++j)
+			{
+				// checksum the name
+				ishtar_memoryChecksumA += (unsigned char)ishtar_services[i].name[j];
+				ishtar_memoryChecksumB += ishtar_memoryChecksumA;
+			}
+
+			// size of this variable in the memory
+			size = (unsigned short)(ishtar_TypeSize(ishtar_services[i].type) * ishtar_services[i].length);
+			// write value to memory
+			if (size != ishtar_memoryWriteFunc(addr, ishtar_services[i].value, size))
+			{
+				ishtar_memoryError = WRITE_ERROR;
+				return;	
+			}	
+			addr += size;
+			ishtar_numberOfBytesWrittenToMemory += size;
+		}
+	}
+
+	// end writing checksum
+	if (ishtar_memoryWriteFunc(ishtar_memoryMinAddress, &ishtar_memoryChecksumA, 1) != 1)
+	{
+		ishtar_memoryError = WRITE_ERROR;
+		return;		
+	}
+	ishtar_numberOfBytesWrittenToMemory += 1;
+	if (ishtar_memoryWriteFunc(ishtar_memoryMinAddress + 1, &ishtar_memoryChecksumB, 1) != 1)
+	{
+		ishtar_memoryError = WRITE_ERROR;
+		return;		
+	}
+	ishtar_numberOfBytesWrittenToMemory += 1;
+
+	ishtar_memoryError = NO_ERROR;
+}
+
+// init
+
+
+/*!
+*	This function inits Ishtar Embedded server
+*
+*	@param externalSendFunc The external function to send data
+*	@param externalFlushFunc The external function to flush data output buffer
+*
+**/
+void ishtar_Init(ishtar_ExternalSendFunc externalSendFunc, ishtar_ExternalFlushFunc externalFlushFunc)
+{
+	ishtar_externalSendFunc = externalSendFunc;
+	ishtar_externalSendBlockingFunc = externalSendFunc;
+	ishtar_currentSendFunc = externalSendFunc;
+
+	if (externalFlushFunc)
+	{
+		ishtar_externalFlushFunc = externalFlushFunc;
+	}
+	else
+	{
+		ishtar_externalFlushFunc = &ishtar_DoNothing;
+	}
+
+	ishtar_InitBuffer();
+
+	// DEBUG
+#if ISHTAR_DEBUG
+	ishtar_RegisterDebugVars();
+#endif
+
+}
+
+/*!
+*	This function inits Ishtar Embedded server with the use of
+*	a different sending function for big messages.
+*	The HELLO and SERVICE_LIST packets use the blocking function, other packets the non-blocking
+*
+*	WARNING: Using this function may cause the host to stuck for a while when the client asks for
+*	the list of all services, as the blocking function could take *several seconds* to send the data
+*
+*	@param externalSendFunc The external function to send data
+*	@param externalSendBlockFunc The external blocking function to send data (big packets)
+*	@param externalFlushFunc The external function to flush data output buffer
+*
+**/
+void ishtar_InitWithBlock(ishtar_ExternalSendFunc externalSendFunc, ishtar_ExternalSendFunc externalSendBlockFunc, ishtar_ExternalFlushFunc externalFlushFunc)
+{
+	ishtar_externalSendFunc = externalSendFunc;
+	ishtar_externalSendBlockingFunc = externalSendBlockFunc;
+	ishtar_currentSendFunc = externalSendFunc;
+
+	if (externalFlushFunc)
+	{
+		ishtar_externalFlushFunc = externalFlushFunc;
+	}
+	else
+	{
+		ishtar_externalFlushFunc = &ishtar_DoNothing;
+	}
+
+	ishtar_InitBuffer();
+
+	// DEBUG
+#if ISHTAR_DEBUG
+	ishtar_RegisterDebugVars();
+#endif
+}
+
+/*!
+*	This function inits the receive buffers and pointers.
+*/
+void ishtar_InitBuffer()
+{
+	ishtar_bufBegin = ishtar_buffer;
+	ishtar_bufEnd = ishtar_buffer + ISHTAR_BUFFER_SIZE;
+	ishtar_bufPos = ishtar_buffer;
+
+	ishtar_consumePos = ishtar_buffer;
+
+	ishtar_packetBegin = ishtar_buffer;
+}
+
+/*!
+*	This function directly registers several variables to monitor Ishtar itself
+*/
+void ishtar_RegisterDebugVars()
+{
+	ishtar_Variable("ishtar.overflows", (unsigned char*)(&ishtar_numberOfOverflows), UINT, 1, 0);
+	ishtar_Variable("ishtar.variables", (unsigned char*)(&ishtar_numberOfVariables), USHORT, 1, 0);
+	ishtar_Variable("ishtar.dropHeader1", (unsigned char*)(&ishtar_numberOfDropHeader1), UINT, 1, 0);
+	ishtar_Variable("ishtar.dropHeader2", (unsigned char*)(&ishtar_numberOfDropHeader2), UINT, 1, 0);
+	ishtar_Variable("ishtar.dropHeader3", (unsigned char*)(&ishtar_numberOfDropHeader3), UINT, 1, 0);
+	ishtar_Variable("ishtar.dropHeader4", (unsigned char*)(&ishtar_numberOfDropHeader4), UINT, 1, 0);
+	ishtar_Variable("ishtar.dropSize", (unsigned char*)(&ishtar_numberOfDropSize), UINT, 1, 0);
+	ishtar_Variable("ishtar.dropContent", (unsigned char*)(&ishtar_numberOfDropContent), UINT, 1, 0);
+	ishtar_Variable("ishtar.bytesSent", (unsigned char*)(&ishtar_numberOfBytesSent), UINT, 1, 0);
+	ishtar_Variable("ishtar.bytesReceived", (unsigned char*)(&ishtar_numberOfBytesReceived), UINT, 1, 0);
+	ishtar_Variable("ishtar.validMessages", (unsigned char*)(&ishtar_numberOfValidMessages), UINT, 1, 0);
+	ishtar_Variable("ishtar.memoryBytesRead", (unsigned char*)(&ishtar_numberOfBytesReadFromMemory), UINT, 1, 0);
+	ishtar_Variable("ishtar.memoryBytesWritten", (unsigned char*)(&ishtar_numberOfBytesWrittenToMemory), UINT, 1, 0);
+	ishtar_Variable("ishtar.memoryError", (unsigned char*)(&ishtar_memoryError), UCHAR, 1, 0);
+	ishtar_Variable("ishtar.snapshotSize", (unsigned char*)(&ishtar_snapshotSize), UINT, 1, 0);
+}
+
+/*!
+*	This function inits the non-volatile memory access functions
+*
+*	@param memoryReadFunc A pointer to the external function that reads the non-volatile memory
+*	@param memoryWriteFunc A pointer to the external function that writes the non-volatile memory
+*	@param minAddress The lowest memory address that Ishtar is allowed to write
+*	@param maxAddress The highest memory address that Ishtar is allowed to write
+*/
+void ishtar_InitMemoryAccess(ishtar_MemoryReadFunc memoryReadFunc, ishtar_MemoryWriteFunc memoryWriteFunc, unsigned short minAddress, unsigned short maxAddress)
+{
+	ishtar_memoryReadFunc = memoryReadFunc;
+	ishtar_memoryWriteFunc = memoryWriteFunc;
+
+	ishtar_memoryMinAddress = minAddress;
+	ishtar_memoryMaxAddress = maxAddress;
+}
+
+/*!
+*	This function registers a variable into Ishtar in order to make it accessible to external clients
+*
+*	@param name The textual name of the variable. Use '.' character to create sub-groups, e.g. "gps.position.longitude"
+*	@param var A pointer to the real variable or to the root of the array of variables
+*	@param type The type of the variable : BOOL, CHAR, UCHAR, SHORT, USHORT, INT, UINT, FLOAT, DOUBLE
+*	@param length The number of elements in the array, or 1 for a normal variable
+*	@param flags The flags for this variable : 0 or READ_ONLY
+*/
+ishtar_ServiceId ishtar_Variable(const char* name, void* var, ishtar_ValueVectorType type, ishtar_ValueVectorSize length, ishtar_ServiceFlags flags)
+{
+	return ishtar_VariableFeedback(name, var, type, length, flags, 0);
+}
+
+/*!
+*	This function registers a variable into Ishtar in order to make it accessible to external clients
+*
+*	@param name The textual name of the variable. Use '.' character to create sub-groups, e.g. "gps.position.longitude"
+*	@param var A pointer to the real variable or to the root of the array of variables
+*	@param type The type of the variable : BOOL, CHAR, UCHAR, SHORT, USHORT, INT, UINT, FLOAT, DOUBLE
+*	@param length The number of elements in the array, or 1 for a normal variable
+*	@param flags The flags for this variable : 0 or READ_ONLY
+*	@param feedbackFunc Pointer to a function called whenever the corresponding variable is modified.
+*/
+ishtar_ServiceId ishtar_VariableFeedback(const char* name, void* var, ishtar_ValueVectorType type, ishtar_ValueVectorSize length, ishtar_ServiceFlags flags, ishtar_VariableModifiedFunc feedbackFunc)
+{
+	if (ishtar_numberOfVariables < ISHTAR_MAX_NUMBER_OF_SERVICES)
+	{
+		// If the length == 0, then the variable must be read-only because there is no dynamic allocation
+		if (length == 0)
+		{
+			flags |= READ_ONLY;
+		}
+		ishtar_services[ishtar_numberOfVariables].name = name;
+		ishtar_services[ishtar_numberOfVariables].type = type;
+		ishtar_services[ishtar_numberOfVariables].length = length;
+		ishtar_services[ishtar_numberOfVariables].flags = flags;
+		ishtar_services[ishtar_numberOfVariables].value = var;
+		ishtar_services[ishtar_numberOfVariables].inSnapshot = 0;
+		ishtar_services[ishtar_numberOfVariables].feedbackFunc = feedbackFunc;
+		
+
+		return ishtar_numberOfVariables++;
+	}
+	return 0;
+}
+
+
+/*!
+*	This function calculates the length of a zero-terminated string
+*
+*	@param The zero-terminated string for which the length will be calculated
+*	@return The length of the string or ISHTAR_STRING_MAX_SIZE if the string is too long (to prevent from getting stuck)
+*/
+unsigned long ishtar_Strlen(const char * addr)
+{
+	unsigned long l = 0;
+	while (*addr != '\0' && l < ISHTAR_STRING_MAX_SIZE)
+	{
+		++l;
+		++addr;
+	}
+	return l;
+}
+
+/*!
+*	This function returns the number of bytes taken by a variable of a certain type
+*
+*	@param type The IShtar-defined type of the variable : BOOL, CHAR, UCHAR, SHORT, USHORT, INT, UINT, FLOAT, DOUBLE
+*/
+unsigned long ishtar_TypeSize(ishtar_ValueVectorType type)
+{
+	unsigned long size = 0;
+	if (type == CHAR || type == UCHAR || type == BOOL)
+	{
+		size = sizeof(char);
+	}
+	else if (type == SHORT || type == USHORT)
+	{
+		size = sizeof(short);
+	}
+	else if (type == FLOAT || type == INT || type == UINT)
+	{
+		size = sizeof(long);
+	}
+	else if (type == DOUBLE)
+	{
+		size = sizeof(double);
+	}
+	return size;
+}
+
+/*!
+*	This function returns true if the server already received a HELLO message since it started, false otherwise
+*/
+unsigned char ishtar_IsConnected()
+{
+	return ishtar_connected;
+}
+
+unsigned short ishtar_ServiceCount()
+{
+	return ishtar_numberOfVariables;
+}
+
+
+#ifdef __cplusplus
+}
+#endif