Main MRPT website > C++ reference
MRPT logo
List of all members | Public Types | Public Member Functions | Protected Member Functions | Protected Attributes
mrpt::utils::CMemoryStream Class Reference

Detailed Description

This CStream derived class allow using a memory buffer as a CStream.

This class is useful for storing any required set of variables or objects, and then read them to other objects, or storing them to a file, for example.

See also
CStream

Definition at line 29 of file CMemoryStream.h.

#include <mrpt/utils/CMemoryStream.h>

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

Public Types

enum  TSeekOrigin { sFromBeginning = 0, sFromCurrent = 1, sFromEnd = 2 }
 Used in CStream::Seek. More...
 

Public Member Functions

 CMemoryStream ()
 Default constructor. More...
 
 CMemoryStream (const void *data, const uint64_t nBytesInData)
 Constructor to initilize the data in the stream from a block of memory (which is copied), and sets the current stream position at the beginning of the data. More...
 
void assignMemoryNotOwn (const void *data, const uint64_t nBytesInData)
 Initilize the data in the stream from a block of memory which is NEITHER OWNED NOR COPIED by the object, so it must exist during the whole live of the object. More...
 
virtual ~CMemoryStream ()
 Destructor. More...
 
void Clear ()
 Clears the memory buffer. More...
 
void changeSize (uint64_t newSize)
 Change size. More...
 
uint64_t Seek (uint64_t Offset, CStream::TSeekOrigin Origin=sFromBeginning)
 Method for moving to a specified position in the streamed resource. More...
 
uint64_t getTotalBytesCount ()
 Returns the total size of the internal buffer. More...
 
uint64_t getPosition ()
 Method for getting the current cursor position, where 0 is the first byte and TotalBytesCount-1 the last one. More...
 
void * getRawBufferData ()
 Method for getting a pointer to the raw stored data. More...
 
bool saveBufferToFile (const std::string &file_name)
 Saves the entire buffer to a file. More...
 
bool loadBufferFromFile (const std::string &file_name)
 Loads the entire buffer from a file. More...
 
void setAllocBlockSize (uint64_t alloc_block_size)
 Change the size of the additional memory block that is reserved whenever the current block runs too short (default=0x10000 bytes) More...
 
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...
 
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

size_t Read (void *Buffer, size_t Count)
 Method responsible for reading from the stream. More...
 
size_t Write (const void *Buffer, size_t Count)
 Method responsible for writing to the stream. More...
 
void resize (uint64_t newSize)
 Resizes the internal buffer size. More...
 

Protected Attributes

void_ptr_noncopy m_memory
 Internal data. More...
 
uint64_t m_size
 
uint64_t m_position
 
uint64_t m_bytesWritten
 
uint64_t m_alloc_block_size
 
bool m_read_only
 If the memory block does not belong to the object. More...
 

Member Enumeration Documentation

◆ TSeekOrigin

Used in CStream::Seek.

Enumerator
sFromBeginning 
sFromCurrent 
sFromEnd 

Definition at line 41 of file CStream.h.

Constructor & Destructor Documentation

◆ CMemoryStream() [1/2]

mrpt::utils::CMemoryStream::CMemoryStream ( )

Default constructor.

◆ CMemoryStream() [2/2]

mrpt::utils::CMemoryStream::CMemoryStream ( const void *  data,
const uint64_t  nBytesInData 
)

Constructor to initilize the data in the stream from a block of memory (which is copied), and sets the current stream position at the beginning of the data.

See also
assignMemoryNotOwn

◆ ~CMemoryStream()

virtual mrpt::utils::CMemoryStream::~CMemoryStream ( )
virtual

Destructor.

Member Function Documentation

◆ assignMemoryNotOwn()

void mrpt::utils::CMemoryStream::assignMemoryNotOwn ( const void *  data,
const uint64_t  nBytesInData 
)

Initilize the data in the stream from a block of memory which is NEITHER OWNED NOR COPIED by the object, so it must exist during the whole live of the object.

After assigning a block of data with this method, the object becomes "read-only", so further attempts to change the size of the buffer will raise an exception. This method resets the write and read positions to the beginning.

◆ changeSize()

void mrpt::utils::CMemoryStream::changeSize ( uint64_t  newSize)

Change size.

This would be rarely used. Use ">>" operators for writing to stream.

See also
Stream

◆ Clear()

void mrpt::utils::CMemoryStream::Clear ( )

Clears the memory buffer.

◆ CopyFrom()

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

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

◆ getline()

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

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

Returns
false on EOF or any other read error.

◆ getPosition()

uint64_t mrpt::utils::CMemoryStream::getPosition ( )
virtual

Method for getting the current cursor position, where 0 is the first byte and TotalBytesCount-1 the last one.

Implements mrpt::utils::CStream.

◆ getRawBufferData()

void* mrpt::utils::CMemoryStream::getRawBufferData ( )

Method for getting a pointer to the raw stored data.

The lenght in bytes is given by getTotalBytesCount

Referenced by mrpt::utils::CMHPropertiesValuesList::getElemental().

◆ getTotalBytesCount()

uint64_t mrpt::utils::CMemoryStream::getTotalBytesCount ( )
virtual

Returns the total size of the internal buffer.

Implements mrpt::utils::CStream.

Referenced by mrpt::utils::CMHPropertiesValuesList::getElemental().

◆ loadBufferFromFile()

bool mrpt::utils::CMemoryStream::loadBufferFromFile ( const std::string &  file_name)

Loads the entire buffer from a file.

Returns
true on success, false on error

◆ operator<<() [1/2]

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

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

◆ operator<<() [2/2]

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

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

◆ operator>>() [1/2]

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

◆ operator>>() [2/2]

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

◆ printf()

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

◆ printf_vector()

template<typename T >
virtual int void mrpt::utils::CStream::printf_vector ( const char *  fmt,
const std::vector< T > &  V 
)
inlineinherited

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

Definition at line 200 of file CStream.h.

◆ Read()

size_t mrpt::utils::CMemoryStream::Read ( void *  Buffer,
size_t  Count 
)
protectedvirtual

Method responsible for reading from the stream.

Implements mrpt::utils::CStream.

◆ ReadBuffer()

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

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 
)
inlineinherited

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 90 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 
)
inlinevirtualinherited

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 108 of file CStream.h.

◆ ReadObject() [1/2]

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

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)
inherited

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)
inherited

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()

◆ resize()

void mrpt::utils::CMemoryStream::resize ( uint64_t  newSize)
protected

Resizes the internal buffer size.

◆ saveBufferToFile()

bool mrpt::utils::CMemoryStream::saveBufferToFile ( const std::string &  file_name)

Saves the entire buffer to a file.

Returns
true on success, false on error

◆ Seek()

uint64_t mrpt::utils::CMemoryStream::Seek ( uint64_t  Offset,
CStream::TSeekOrigin  Origin = sFromBeginning 
)
virtual

Method for moving to a specified position in the streamed resource.

See also
CStream::Seek

Implements mrpt::utils::CStream.

◆ sendMessage()

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

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

◆ setAllocBlockSize()

void mrpt::utils::CMemoryStream::setAllocBlockSize ( uint64_t  alloc_block_size)
inline

Change the size of the additional memory block that is reserved whenever the current block runs too short (default=0x10000 bytes)

Definition at line 110 of file CMemoryStream.h.

References ASSERT_.

◆ Write()

size_t mrpt::utils::CMemoryStream::Write ( const void *  Buffer,
size_t  Count 
)
protectedvirtual

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.

Implements mrpt::utils::CStream.

◆ WriteBuffer()

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

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 
)
inlineinherited

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 134 of file CStream.h.

◆ WriteObject()

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

Writes an object to the stream.

Member Data Documentation

◆ m_alloc_block_size

uint64_t mrpt::utils::CMemoryStream::m_alloc_block_size
protected

Definition at line 45 of file CMemoryStream.h.

◆ m_bytesWritten

uint64_t mrpt::utils::CMemoryStream::m_bytesWritten
protected

Definition at line 44 of file CMemoryStream.h.

◆ m_memory

void_ptr_noncopy mrpt::utils::CMemoryStream::m_memory
protected

Internal data.

Definition at line 43 of file CMemoryStream.h.

◆ m_position

uint64_t mrpt::utils::CMemoryStream::m_position
protected

Definition at line 44 of file CMemoryStream.h.

◆ m_read_only

bool mrpt::utils::CMemoryStream::m_read_only
protected

If the memory block does not belong to the object.

Definition at line 46 of file CMemoryStream.h.

◆ m_size

uint64_t mrpt::utils::CMemoryStream::m_size
protected

Definition at line 44 of file CMemoryStream.h.




Page generated by Doxygen 1.8.14 for MRPT 1.1.0 SVN: at lun oct 28 00:54:49 CET 2019 Hosted on:
SourceForge.net Logo