ossimNmeaMessage Class Reference

#include <ossimNmeaMessage.h>

Inheritance diagram for ossimNmeaMessage:

Public Types
typedef std::vector< ossimString >	FieldListType

Public Member Functions
	ossimNmeaMessage (const std::string &acceptedStartingCharacters="!$")
virtual void	parseMessage (std::istream &in) throw (ossimException)
	Parses a standard formatted NMEA message. More...
virtual bool	valid () const
bool	validCheckSum () const
ossim_uint32	numberOfFields () const
const std::string &	getField (ossim_uint32 idx)
const std::string &	operator[] (int idx) const
void	setStartChars (const std::string &acceptedStartingCharacters="!$")
virtual void	reset ()
const std::string &	message () const
Public Member Functions inherited from ossimReferenced
	ossimReferenced ()
	ossimReferenced (const ossimReferenced &)
ossimReferenced &	operator= (const ossimReferenced &)
void	ref () const
	increment the reference count by one, indicating that this object has another pointer which is referencing it. More...
void	unref () const
	decrement the reference count by one, indicating that a pointer to this object is referencing it. More...
void	unref_nodelete () const
	decrement the reference count by one, indicating that a pointer to this object is referencing it. More...
int	referenceCount () const

Static Public Member Functions
static ossim_uint32	checksum (std::string::const_iterator start, std::string::const_iterator end)

Protected Member Functions
virtual void	setFields (std::string::const_iterator start, std::string::const_iterator end)
bool	isValidStartChar (char c) const
Protected Member Functions inherited from ossimReferenced
virtual	~ossimReferenced ()

Protected Attributes
std::string	m_message
FieldListType	m_fields
bool	m_validCheckSum
std::string	m_startChars

Detailed Description

Definition at line 26 of file ossimNmeaMessage.h.

Member Typedef Documentation

FieldListType

typedef std::vector<ossimString> ossimNmeaMessage::FieldListType

Definition at line 29 of file ossimNmeaMessage.h.

Constructor & Destructor Documentation

ossimNmeaMessage()

ossimNmeaMessage::ossimNmeaMessage ( const std::string &  acceptedStartingCharacters = "!$" )

inline

Definition at line 31 of file ossimNmeaMessage.h.

:m_startChars(acceptedStartingCharacters){}

Member Function Documentation

checksum()

ossim_uint32 ossimNmeaMessage::checksum ( std::string::const_iterator  start, std::string::const_iterator  end  )

static

Definition at line 18 of file ossimNmeaMessage.cpp.

{
   ossim_uint32 sum = 0;
   
   while(start!=end&&((*start)!='*'))
   {
      sum ^= ((*start)%128);
      ++start;
   }
   return sum;
}

getField()

const std::string& ossimNmeaMessage::getField ( ossim_uint32  idx )

inline

Definition at line 45 of file ossimNmeaMessage.h.

   {
      static ossimString empty="";
      
      if(idx < m_fields.size()) return m_fields[idx];
      
      return empty;
   }

isValidStartChar()

bool ossimNmeaMessage::isValidStartChar ( char  c ) const

protected

Definition at line 53 of file ossimNmeaMessage.cpp.

References m_startChars.

{
   std::string::const_iterator iter = std::find(m_startChars.begin(), m_startChars.end(), c);
   return (iter != m_startChars.end());
}

message()

const std::string& ossimNmeaMessage::message ( ) const

inline

Definition at line 69 of file ossimNmeaMessage.h.

{return m_message;}

numberOfFields()

ossim_uint32 ossimNmeaMessage::numberOfFields ( ) const

inline

Definition at line 43 of file ossimNmeaMessage.h.

{return m_fields.size();}

operator[]()

const std::string& ossimNmeaMessage::operator[] ( int  idx ) const

inline

Definition at line 53 of file ossimNmeaMessage.h.

   {
      static ossimString empty="";
      
      if ( idx < static_cast<int>( m_fields.size() ) ) return m_fields[idx];
      
      return empty;
   }

parseMessage()

void ossimNmeaMessage::parseMessage ( std::istream &  in ) throw ( ossimException )

virtual

Parses a standard formatted NMEA message.

No exceptions are created for checksums. The checksum needs to be checked after parsing by calling validCheckSum().

Definition at line 60 of file ossimNmeaMessage.cpp.

References ossimString::downcase(), and ossim::skipws().

Referenced by ossimNmeaMessageSequencer::next().

{
   ossim::skipws(in);
   m_validCheckSum = false;
   m_message = "";
   if(!isValidStartChar(static_cast<char>(in.peek())))
   {
      throw ossimException(ossimString("Starting NMEA message indicator not found, expected one of ") +
                           m_startChars + " but found " +
                           ossimString((char)in.peek()));
   }
   
   char c = static_cast<char>(in.get());
   while(((c!='\n')&&(c!='\r'))&&
         !in.eof()&&!in.bad()) 
   {
      m_message += c;
      c = static_cast<char>(in.get());
   }
   std::string::iterator iter = std::find(m_message.begin(), m_message.end(), '*');
   
   if(iter != m_message.end())
   {
      setFields(m_message.begin()+1, m_message.end());
      ossim_uint32 check = checksum(m_message.begin()+1, iter);
      std::ostringstream out;
      out << std::setw(2) << std::setfill('0') << std::hex << check;
      std::string::iterator endChecksumIter = iter+1;
      while((endChecksumIter!= m_message.end())&&(*endChecksumIter!=',')) ++endChecksumIter;
      if(out.str() == ossimString(iter+1, endChecksumIter).downcase()) 
      {
         m_validCheckSum = true;
      }
   }
   else
   {
      throw ossimException("Terminating * indicator for cbecksum not found in NMEA message format");
   }
}

reset()

virtual void ossimNmeaMessage::reset ( void  )

inlinevirtual

Definition at line 63 of file ossimNmeaMessage.h.

   {
      m_fields.clear();
      m_message = "";
      m_validCheckSum = false;
   }

setFields()

void ossimNmeaMessage::setFields ( std::string::const_iterator  start, std::string::const_iterator  end  )

protectedvirtual

Definition at line 30 of file ossimNmeaMessage.cpp.

References m_fields.

{
   m_fields.clear();
   ossim_uint32 idx = 0;
   while(start != end)
   {
      m_fields.push_back("");
      
      while((start!=end)&&
            (*start!=','))
      {
         m_fields[idx]+=*start;
         ++start;
      }
      
      if(start!=end)
      {
         ++start;
      }
      ++idx;
   }
}

setStartChars()

void ossimNmeaMessage::setStartChars ( const std::string &  acceptedStartingCharacters = "!$" )

inline

Definition at line 61 of file ossimNmeaMessage.h.

{m_startChars = acceptedStartingCharacters;}

valid()

virtual bool ossimNmeaMessage::valid ( ) const

inlinevirtual

Definition at line 39 of file ossimNmeaMessage.h.

{return validCheckSum();}

validCheckSum()

bool ossimNmeaMessage::validCheckSum ( ) const

inline

Definition at line 40 of file ossimNmeaMessage.h.

{return m_validCheckSum;}

Member Data Documentation

m_fields

FieldListType ossimNmeaMessage::m_fields

protected

Definition at line 79 of file ossimNmeaMessage.h.

Referenced by setFields().

m_message

std::string ossimNmeaMessage::m_message

protected

Definition at line 78 of file ossimNmeaMessage.h.

m_startChars

std::string ossimNmeaMessage::m_startChars

protected

Definition at line 82 of file ossimNmeaMessage.h.

Referenced by isValidStartChar().

m_validCheckSum

bool ossimNmeaMessage::m_validCheckSum

protected

Definition at line 81 of file ossimNmeaMessage.h.

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The documentation for this class was generated from the following files:

• ossimNmeaMessage.h
• ossimNmeaMessage.cpp