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mrpt::utils::CStream Class Reference


Detailed Description

This base class is used to provide a unified interface to files,memory buffers,..Please see the derived classes.

This class is largely inspired by Borland VCL "TStream" class.

Apart of the "VCL like" methods, operators ">>" and "<<" have been defined so that simple types (int,bool,char,float,char *,std::string,...) can be directly written and read to and from any CStream easily. Please, it is recomendable to read CSerializable documentation also.

See also:
CFileStream, CMemoryStream,CSerializable

Definition at line 54 of file CStream.h.

#include <mrpt/utils/CStream.h>

Inheritance diagram for mrpt::utils::CStream:
Inheritance graph
[legend]

List of all members.

Public Types

enum  TSeekOrigin { sFromBeginning = 0, sFromCurrent = 1, sFromEnd = 2 }
 

Used in CStream::Seek.

More...

Public Member Functions

 CStream ()
virtual ~CStream ()
size_t ReadBuffer (void *Buffer, size_t Count)
 Reads a block of bytes from the stream into Buffer

Exceptions:
std::exception On any error, or if ZERO bytes are read.

template<typename T >
size_t ReadBufferFixEndianness (T *ptr, size_t ElementCount)
 Reads a sequence of elemental datatypes, taking care of reordering their bytes from the MRPT stream standard (little endianness) to the format of the running architecture.
virtual size_t ReadBufferImmediate (void *Buffer, size_t Count)
 Reads a block of bytes from the stream into Buffer, and returns the amound of bytes actually read, without waiting for more extra bytes to arrive (just those already enqued in the stream).
void WriteBuffer (const void *Buffer, size_t Count)
 Writes a block of bytes to the stream from Buffer.
template<typename T >
void WriteBufferFixEndianness (const T *ptr, size_t ElementCount)
 Writes a sequence of elemental datatypes, taking care of reordering their bytes from the running architecture to MRPT stream standard (little endianness).
size_t CopyFrom (CStream *Source, size_t Count)
 Copies a specified number of bytes from one stream to another.
virtual uint64_t Seek (long Offset, CStream::TSeekOrigin Origin=sFromBeginning)=0
 Introduces a pure virtual method for moving to a specified position in the streamed resource.
virtual uint64_t getTotalBytesCount ()=0
 Returns the total amount of bytes in the stream.
virtual uint64_t getPosition ()=0
 Method for getting the current cursor position, where 0 is the first byte and TotalBytesCount-1 the last one.
void WriteObject (const CSerializable *o)
 Writes an object to the stream.
CSerializablePtr ReadObject ()
 Reads an object from stream, its class determined at runtime, and returns a smart pointer to the object.
void ReadObject (CSerializable *existingObj)
 Reads an object from stream, where its class must be the same as the supplied object, where the loaded object will be stored in.
CStreamoperator<< (const CSerializablePtr &pObj)
 Write an object to a stream in the binary MRPT format.
CStreamoperator<< (const CSerializable &obj)
 Write an object to a stream in the binary MRPT format.
CStreamoperator>> (CSerializablePtr &pObj)
CStreamoperator>> (CSerializable &obj)
virtual int printf (const char *fmt,...) MRPT_printf_format_check(2
 Writes a string to the stream in a textual form.
template<typename T >
virtual int void printf_vector (const char *fmt, const std::vector< T > &V)
 Prints a vector in the format [A,B,C,...] using CStream::printf, and the fmt string for each vector element.
void sendMessage (const utils::CMessage &msg)
 Send a message to the device.
bool receiveMessage (utils::CMessage &msg)
 Tries to receive a message from the device.
bool getline (std::string &out_str)
 Reads from the stream until a '
' character is found ('' characters are ignored).

Protected Member Functions

virtual size_t Read (void *Buffer, size_t Count)=0
 Introduces a pure virtual method responsible for reading from the stream.
virtual size_t Write (const void *Buffer, size_t Count)=0
 Introduces a pure virtual method responsible for writing to the stream.

Member Enumeration Documentation

Used in CStream::Seek.

Enumerator:
sFromBeginning 
sFromCurrent 
sFromEnd 

Definition at line 59 of file CStream.h.


Constructor & Destructor Documentation

mrpt::utils::CStream::CStream (  )  [inline]

Definition at line 78 of file CStream.h.

virtual mrpt::utils::CStream::~CStream (  )  [virtual]

Member Function Documentation

size_t mrpt::utils::CStream::CopyFrom ( CStream Source,
size_t  Count 
)

Copies a specified number of bytes from one stream to another.

bool mrpt::utils::CStream::getline ( std::string &  out_str  ) 

Reads from the stream until a '
' character is found ('' characters are ignored).

Returns:
false on EOF or any other read error.
virtual uint64_t mrpt::utils::CStream::getPosition (  )  [pure virtual]
virtual uint64_t mrpt::utils::CStream::getTotalBytesCount (  )  [pure virtual]
CStream& mrpt::utils::CStream::operator<< ( const CSerializable obj  ) 

Write an object to a stream in the binary MRPT format.

CStream& mrpt::utils::CStream::operator<< ( const CSerializablePtr pObj  ) 

Write an object to a stream in the binary MRPT format.

CStream& mrpt::utils::CStream::operator>> ( CSerializablePtr pObj  ) 
CStream& mrpt::utils::CStream::operator>> ( CSerializable obj  ) 
virtual int mrpt::utils::CStream::printf ( const char *  fmt,
  ... 
) [virtual]

Writes a string to the stream in a textual form.

See also:
CStdOutStream
template<typename T >
virtual int void mrpt::utils::CStream::printf_vector ( const char *  fmt,
const std::vector< T > &  V 
) [inline]

Prints a vector in the format [A,B,C,...] using CStream::printf, and the fmt string for each vector element.

Definition at line 218 of file CStream.h.

virtual size_t mrpt::utils::CStream::Read ( void *  Buffer,
size_t  Count 
) [protected, pure virtual]
size_t mrpt::utils::CStream::ReadBuffer ( void *  Buffer,
size_t  Count 
)

Reads a block of bytes from the stream into Buffer

Exceptions:
std::exception On any error, or if ZERO bytes are read.

Returns:
The amound of bytes actually read.
Note:
This method is endianness-dependent.
See also:
ReadBufferImmediate ; Important, see: ReadBufferFixEndianness,
template<typename T >
size_t mrpt::utils::CStream::ReadBufferFixEndianness ( T *  ptr,
size_t  ElementCount 
) [inline]

Reads a sequence of elemental datatypes, taking care of reordering their bytes from the MRPT stream standard (little endianness) to the format of the running architecture.

Parameters:
ElementCount The number of elements (not bytes) to read.
ptr A pointer to the first output element in an array (or std::vector<>, etc...).
Returns:
The amound of *bytes* (not elements) actually read (under error situations, the last element may be invalid if the data stream abruptly ends). Example of usage:
   uint32_t  N;
   s >> N;
   vector<float>  vec(N);
   if (N) 
     s.ReadBufferFixEndianness<float>(&vec[0],N);
Exceptions:
std::exception On any error, or if ZERO bytes are read.
See also:
ReadBufferFixEndianness, ReadBuffer

Definition at line 108 of file CStream.h.

References mrpt::utils::reverseBytesInPlace().

Referenced by mrpt::math::operator>>().

virtual size_t mrpt::utils::CStream::ReadBufferImmediate ( void *  Buffer,
size_t  Count 
) [inline, virtual]

Reads a block of bytes from the stream into Buffer, and returns the amound of bytes actually read, without waiting for more extra bytes to arrive (just those already enqued in the stream).

Note that this method will fallback to ReadBuffer() in most CStream classes but in some hardware-related classes.

Exceptions:
std::exception On any error, or if ZERO bytes are read.

Reimplemented in mrpt::hwdrivers::CInterfaceFTDI.

Definition at line 126 of file CStream.h.

CSerializablePtr mrpt::utils::CStream::ReadObject (  ) 

Reads an object from stream, its class determined at runtime, and returns a smart pointer to the object.

Exceptions:
std::exception On I/O error or undefined class.
mrpt::utils::CExceptionEOF On an End-Of-File condition found at a correct place: an EOF that abruptly finishes in the middle of one object raises a plain std::exception instead.

Referenced by mrpt::math::operator>>().

void mrpt::utils::CStream::ReadObject ( CSerializable existingObj  ) 

Reads an object from stream, where its class must be the same as the supplied object, where the loaded object will be stored in.

Exceptions:
std::exception On I/O error or different class found.
mrpt::utils::CExceptionEOF On an End-Of-File condition found at a correct place: an EOF that abruptly finishes in the middle of one object raises a plain std::exception instead.
bool mrpt::utils::CStream::receiveMessage ( utils::CMessage msg  ) 

Tries to receive a message from the device.

Exceptions:
std::exception On communication errors
Returns:
True if successful, false if there is no new data from the device (but communications seem to work fine)
See also:
The frame format is described in sendMessage()
virtual uint64_t mrpt::utils::CStream::Seek ( long  Offset,
CStream::TSeekOrigin  Origin = sFromBeginning 
) [pure virtual]

Introduces a pure virtual method for moving to a specified position in the streamed resource.

he Origin parameter indicates how to interpret the Offset parameter. Origin should be one of the following values:

  • sFromBeginning (Default) Offset is from the beginning of the resource. Seek moves to the position Offset. Offset must be >= 0.
  • sFromCurrent Offset is from the current position in the resource. Seek moves to Position + Offset.
  • sFromEnd Offset is from the end of the resource. Offset must be <= 0 to indicate a number of bytes before the end of the file.
    Returns:
    Seek returns the new value of the Position property.

Implemented in mrpt::utils::CClientTCPSocket, mrpt::utils::CFileGZInputStream, mrpt::utils::CFileInputStream, mrpt::utils::CFileOutputStream, mrpt::utils::CFileStream, mrpt::utils::CMemoryStream, mrpt::utils::CStdOutStream, mrpt::hwdrivers::CInterfaceFTDI, and mrpt::hwdrivers::CSerialPort.

void mrpt::utils::CStream::sendMessage ( const utils::CMessage msg  ) 

Send a message to the device.

Note that only the low byte from the "type" field will be used.

For frames of size < 255 the frame format is an array of bytes in this order:

  <START_FLAG> <HEADER> <LENGTH> <BODY> <END_FLAG>
        <START_FLAG>    = 0x69
        <HEADER>                = A header byte
        <LENGHT>                = Number of bytes of BODY
        <BODY>                  = N x bytes
        <END_FLAG>              = 0X96
  Total length  =       <LENGTH> + 4

For frames of size > 255 the frame format is an array of bytes in this order:

  <START_FLAG> <HEADER> <HIBYTE(LENGTH)> <LOBYTE(LENGTH)> <BODY> <END_FLAG>
        <START_FLAG>    = 0x79
        <HEADER>                = A header byte
        <LENGHT>                = Number of bytes of BODY
        <BODY>                  = N x bytes
        <END_FLAG>              = 0X96
  Total length  =       <LENGTH> + 5
Exceptions:
std::exception On communication errors
virtual size_t mrpt::utils::CStream::Write ( const void *  Buffer,
size_t  Count 
) [protected, pure virtual]

Introduces a pure virtual method responsible for writing to the stream.

Write attempts to write up to Count bytes to Buffer, and returns the number of bytes actually written.

Implemented in mrpt::utils::CClientTCPSocket, mrpt::utils::CFileGZInputStream, mrpt::utils::CFileInputStream, mrpt::utils::CFileOutputStream, mrpt::utils::CFileStream, mrpt::utils::CMemoryStream, mrpt::utils::CStdOutStream, mrpt::hwdrivers::CInterfaceFTDI, and mrpt::hwdrivers::CSerialPort.

void mrpt::utils::CStream::WriteBuffer ( const void *  Buffer,
size_t  Count 
)

Writes a block of bytes to the stream from Buffer.

Exceptions:
std::exception On any error
See also:
Important, see: WriteBufferFixEndianness
Note:
This method is endianness-dependent.
template<typename T >
void mrpt::utils::CStream::WriteBufferFixEndianness ( const T *  ptr,
size_t  ElementCount 
) [inline]

Writes a sequence of elemental datatypes, taking care of reordering their bytes from the running architecture to MRPT stream standard (little endianness).

Parameters:
ElementCount The number of elements (not bytes) to write.
ptr A pointer to the first input element in an array (or std::vector<>, etc...). Example of usage:

   vector<float>  vec = ...
   uint32_t N = vec.size();
   s << N
   if (N) 
     s.WriteBufferFixEndianness<float>(&vec[0],N);
Exceptions:
std::exception On any error
See also:
WriteBuffer

Definition at line 152 of file CStream.h.

void mrpt::utils::CStream::WriteObject ( const CSerializable o  ) 

Writes an object to the stream.




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