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databuf Class Reference

Inherits constbuf.

Inherited by dynbuf.

List of all members.

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Detailed Description

A mutable data buffer.

Basically equivalent to a pair<void *, size_t>: this is just a convenient way of passing a reference to a mutable data buffer.

A databuf actually contains both a "current length" and a "maximum length" for the data buffer; for instance, one may allocate n bytes of storage, and the constructor databuf(mem, 0, n) to reflect the fact that there is currently no data in the buffer but that it has space for a kilobyte of data. Input routines such as IOHandle::read generally read up to max_length() bytes and use set_length() to reflect the number of bytes actually nead.

    char *mem = malloc(1024);
    databuf buf(mem, 0, 1024);
    my_iohandle.read(buf); // read up to 1024 bytes
    cout << "I just read " << buf.length() << " bytes" << endl;

Note that a databuf may be cast to a constbuf (just as a void * can be implicitly cast to a const void *) but not vice versa.

Public Methods
	databuf ()
	Null constructor.
	databuf (void *dat, unsigned int len)
	Constructs a reference to a mutable data buffer.
	databuf (void *dat, unsigned int len, unsigned int maxlen)
	Constructs a reference to a mutable data buffer whose size may change.
char *	data ()
	Returns a pointer to the beginning of the data buffer.
void	set_length (unsigned int len)
	Modifies the length of the data buffer.
unsigned int	max_length () const
	Returns the maximum length of the data buffer.
Protected Attributes
unsigned int	maxlen

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Constructor & Destructor Documentation

databuf::databuf (    )

Null constructor.

databuf::databuf (  void *    dat, unsigned int    len )

Constructs a reference to a mutable data buffer. Both its current length and maximum length are len.

databuf::databuf (  void *    dat, unsigned int    len, unsigned int    maxlen )

Constructs a reference to a mutable data buffer whose size may change. Parameters: dat  a pointer to the data buffer. len  the current length of the data buffer. maxlen  the maximum length of the data buffer.

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Member Function Documentation

char* databuf::data (    )

Returns a pointer to the beginning of the data buffer.

unsigned int databuf::max_length (    )  const

Returns the maximum length of the data buffer.

void databuf::set_length (  unsigned int    len )

Modifies the length of the data buffer.

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Member Data Documentation

unsigned int databuf::maxlen [protected]

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

• io

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