RWAuditStreamBuffer Class Reference

Constructs a stream and audits the bytes that pass through it. More...

#include <rw/auditbuf.h>

Inherits std::streambuf.

Public Member Functions
	RWAuditStreamBuffer ()
	RWAuditStreamBuffer (RWauditFunction, void *=0)
	RWAuditStreamBuffer (std::iostream &, RWauditFunction=0, void *=0)
	RWAuditStreamBuffer (std::istream &, RWauditFunction=0, void *=0)
	RWAuditStreamBuffer (std::ostream &, RWauditFunction=0, void *=0)
	RWAuditStreamBuffer (std::streambuf *, RWauditFunction=0, void *=0)
	operator unsigned long ()
unsigned long	reset (unsigned long val=0ul)

Related Symbols
(Note that these are not member symbols.)
typedef void(*	RWauditFunction) (unsigned char, void *)

Detailed Description

Class RWAuditStreamBuffer is used to construct a stream, after which the RWAuditStreamBuffer instance counts all the bytes that pass through the stream. If constructed with a function pointer, RWAuditStreamBuffer calls that function with each byte that passes through the stream. The counting capacity provides for streams the equivalent of the method RWCollectable::recursiveStoreSize(), which is available only for RWFile.

Synopsis

#include <rw/auditbuf.h>
#include <iostream>
 
RWAuditStreamBuffer buf;
std::ostream os(&buf);  // may be used for ostreams
std::istream is(&buf);  // or istreams of any kind

Example

#include <rw/auditbuf.h>
#include <rw/bstream.h>
#include <rw/pstream.h>
 
#include <rw/collint.h>   // for RWCollectableInt
#include <rw/collstr.h>   // for RWCollectableString
#include <rw/dlistcol.h>  // for RWDlistCollectables
 
#include <iostream>
 
int main() {
  RWCollectableInt i(7);
  RWCollectableString s("Hello!\n");
 
  RWDlistCollectables ct;
 
  // Construct a collection
  ct.append(&i);
  ct.append(&s);
  ct.prepend(&ct);
 
  RWAuditStreamBuffer bcounter, pcounter;
 
  RWbostream bcount(&bcounter);  // ctor takes streambuf pointer
  RWpostream pcount(&pcounter);
 
  bcount << ct;
  pcount << ct;
 
  std::cout << "We just counted " << bcounter
            << " bytes from an RWbostream.\n";
  std::cout << "We just counted " << pcounter
            << " bytes from an RWpostream." << std::endl;
 
  return 0;
}

Program output:

We just counted 43 bytes from an RWbostream.
We just counted 52 bytes from an RWpostream.

See also

RWAuditStreamBuffer may be used as the std::streambuf for any stream, including those derived from RWvostream or RWvistream, std::strstream, std::ifstream, std::ofstream, etc.

Persistence

None

Constructor & Destructor Documentation

RWAuditStreamBuffer() [1/6]

RWAuditStreamBuffer::RWAuditStreamBuffer

(

)

Constructs a new RWAuditStreamBuffer that may be used only to examine and count every byte that passes into an std::ostream that has the RWAuditStreamBuffer instance as its std::streambuf. It does not forward the bytes to any stream, nor accept bytes from a stream.

RWAuditStreamBuffer() [2/6]

RWAuditStreamBuffer::RWAuditStreamBuffer	(	RWauditFunction	,
		void *	= 0 )

Constructs a new RWAuditStreamBuffer that may be used only to examine and count every byte that passes into an std::ostream that has the RWAuditStreamBuffer instance as its std::streambuf. It does not forward the bytes to any stream, nor accept bytes from a stream. The second parameter to the constructor allows you to supply storage for the byte count. It is optional.

RWAuditStreamBuffer() [3/6]

RWAuditStreamBuffer::RWAuditStreamBuffer	(	std::istream &	,
		RWauditFunction	= 0,
		void *	= 0 )

Constructs a new RWAuditStreamBuffer that passes bytes from the std::istream on which it is constructed to the std::istream that has the RWAuditStreamBuffer instance as its std::streambuf. A typical use would be to count or examine the bytes being input from a file through a stream derived from RWvistream. The third parameter to the constructor allows you to supply storage for the byte count. It is optional.

RWAuditStreamBuffer() [4/6]

RWAuditStreamBuffer::RWAuditStreamBuffer	(	std::iostream &	,
		RWauditFunction	= 0,
		void *	= 0 )

Constructs a new RWAuditStreamBuffer that passes bytes to and from the std::iostream on which it is constructed to and from the std::istream that has the RWAuditStreamBuffer instance as its std::streambuf. A typical use would be to count or examine the bytes being transferred to and from a file used to store and retrieve changing data. The third parameter to the constructor allows you to supply storage for the byte count. It is optional.

RWAuditStreamBuffer() [5/6]

RWAuditStreamBuffer::RWAuditStreamBuffer	(	std::ostream &	,
		RWauditFunction	= 0,
		void *	= 0 )

Constructs a new RWAuditStreamBuffer that passes bytes into the std::ostream on which it is constructed from the std::ostream that has the RWAuditStreamBuffer instance as its std::streambuf. A typical use would be to count or examine the bytes being output to a file through a stream derived from RWvostream. The third parameter to the constructor allows you to supply storage for the byte count. It is optional.

RWAuditStreamBuffer() [6/6]

RWAuditStreamBuffer::RWAuditStreamBuffer	(	std::streambuf *	,
		RWauditFunction	= 0,
		void *	= 0 )

Constructs a new RWAuditStreamBuffer that passes bytes into the std::ostream on which it is constructed from the std::ostream that has the RWAuditStreamBuffer instance as its std::streambuf. A typical use would be to count or examine the bytes being output to a file through a stream derived from RWvostream. The third parameter to the constructor allows you to supply storage for the byte count. It is optional.

Member Function Documentation

operator unsigned long()

RWAuditStreamBuffer::operator unsigned long ( )

inline

Provides the count of bytes seen so far.

reset()

unsigned long RWAuditStreamBuffer::reset ( unsigned long val = 0ul )

inline

Resets the count of bytes seen so far. Returns the current count.

Friends And Related Symbol Documentation

RWauditFunction

typedef void(* RWauditFunction) (unsigned char, void *)

related

If you wish to do more than count each character handled by the buffer, you may provide an RWauditFunction to the constructor. The first parameter to this function is a byte provided by the stream. The second parameter is the address of the counter to be manipulated by RWAuditFunction.