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mrpt::utils::CStream Class Referenceabstract

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 62 of file CStream.h.

#include <mrpt/utils/CStream.h>

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

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. More...
 
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. More...
 
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). More...
 
void WriteBuffer (const void *Buffer, size_t Count)
 Writes a block of bytes to the stream from Buffer. More...
 
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). More...
 
size_t CopyFrom (CStream *Source, size_t Count)
 Copies a specified number of bytes from one stream to another. More...
 
virtual uint64_t Seek (uint64_t Offset, CStream::TSeekOrigin Origin=sFromBeginning)=0
 Introduces a pure virtual method for moving to a specified position in the streamed resource. More...
 
virtual uint64_t getTotalBytesCount ()=0
 Returns the total amount of bytes in the stream. More...
 
virtual uint64_t getPosition ()=0
 Method for getting the current cursor position, where 0 is the first byte and TotalBytesCount-1 the last one. More...
 
void WriteObject (const CSerializable *o)
 Writes an object to the stream. More...
 
CSerializablePtr ReadObject ()
 Reads an object from stream, its class determined at runtime, and returns a smart pointer to the object. More...
 
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. More...
 
CStreamoperator<< (const CSerializablePtr &pObj)
 Write an object to a stream in the binary MRPT format. More...
 
CStreamoperator<< (const CSerializable &obj)
 Write an object to a stream in the binary MRPT format. More...
 
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. More...
 
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. More...
 
void sendMessage (const utils::CMessage &msg)
 Send a message to the device. More...
 
bool receiveMessage (utils::CMessage &msg)
 Tries to receive a message from the device. More...
 
bool getline (std::string &out_str)
 Reads from the stream until a '
' character is found ('' characters are ignored). More...
 

Protected Member Functions

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

Member Enumeration Documentation

◆ TSeekOrigin

Used in CStream::Seek.

Enumerator
sFromBeginning 
sFromCurrent 
sFromEnd 

Definition at line 67 of file CStream.h.

Constructor & Destructor Documentation

◆ CStream()

mrpt::utils::CStream::CStream ( )
inline

Definition at line 86 of file CStream.h.

◆ ~CStream()

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

Member Function Documentation

◆ CopyFrom()

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

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

◆ getline()

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.

◆ getPosition()

virtual uint64_t mrpt::utils::CStream::getPosition ( )
pure virtual

◆ getTotalBytesCount()

virtual uint64_t mrpt::utils::CStream::getTotalBytesCount ( )
pure virtual

◆ operator<<() [1/2]

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

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

◆ operator<<() [2/2]

CStream& mrpt::utils::CStream::operator<< ( const CSerializable obj)

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

◆ operator>>() [1/2]

CStream& mrpt::utils::CStream::operator>> ( CSerializablePtr pObj)

◆ operator>>() [2/2]

CStream& mrpt::utils::CStream::operator>> ( CSerializable obj)

◆ printf()

virtual int mrpt::utils::CStream::printf ( const char *  fmt,
  ... 
)
virtual

Writes a string to the stream in a textual form.

See also
CStdOutStream

Referenced by mrpt::bayes::TKF_options::dumpToTextStream().

◆ printf_vector()

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 226 of file CStream.h.

◆ Read()

virtual size_t mrpt::utils::CStream::Read ( void *  Buffer,
size_t  Count 
)
protectedpure virtual

◆ ReadBuffer()

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

Reads a block of bytes from the stream into Buffer.

Exceptions
std::exceptionOn 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,

◆ 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
ElementCountThe number of elements (not bytes) to read.
ptrA 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::exceptionOn any error, or if ZERO bytes are read.
See also
ReadBufferFixEndianness, ReadBuffer

Definition at line 116 of file CStream.h.

References mrpt::mrpt::utils::reverseBytesInPlace().

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

◆ ReadBufferImmediate()

virtual size_t mrpt::utils::CStream::ReadBufferImmediate ( void *  Buffer,
size_t  Count 
)
inlinevirtual

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::exceptionOn any error, or if ZERO bytes are read.

Reimplemented in mrpt::hwdrivers::CInterfaceFTDI.

Definition at line 134 of file CStream.h.

◆ ReadObject() [1/2]

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::exceptionOn I/O error or undefined class.
mrpt::utils::CExceptionEOFOn 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>>().

◆ ReadObject() [2/2]

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::exceptionOn I/O error or different class found.
mrpt::utils::CExceptionEOFOn 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.

◆ receiveMessage()

bool mrpt::utils::CStream::receiveMessage ( utils::CMessage msg)

Tries to receive a message from the device.

Exceptions
std::exceptionOn 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()

◆ Seek()

virtual uint64_t mrpt::utils::CStream::Seek ( uint64_t  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::CFileStream, mrpt::utils::CFileGZInputStream, mrpt::utils::CMemoryStream, mrpt::utils::CFileOutputStream, mrpt::utils::CFileInputStream, and mrpt::utils::CStdOutStream.

◆ sendMessage()

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::exceptionOn communication errors

◆ Write()

virtual size_t mrpt::utils::CStream::Write ( const void *  Buffer,
size_t  Count 
)
protectedpure 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::hwdrivers::CInterfaceFTDI, mrpt::hwdrivers::CSerialPort, mrpt::utils::CClientTCPSocket, mrpt::utils::CFileStream, mrpt::utils::CFileGZInputStream, mrpt::utils::CStdOutStream, mrpt::utils::CMemoryStream, mrpt::utils::CFileInputStream, and mrpt::utils::CFileOutputStream.

◆ WriteBuffer()

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

Writes a block of bytes to the stream from Buffer.

Exceptions
std::exceptionOn any error
See also
Important, see: WriteBufferFixEndianness
Note
This method is endianness-dependent.

◆ WriteBufferFixEndianness()

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
ElementCountThe number of elements (not bytes) to write.
ptrA 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::exceptionOn any error
See also
WriteBuffer

Definition at line 160 of file CStream.h.

◆ WriteObject()

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

Writes an object to the stream.




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