SocketSource
Documentation |
#include <cryptopp/socketft.h>
|
In the pipelining paradigm, SocketSources are an origin of data.
The SocketSource
takes a pointer to a BufferedTransformation
. Because a pointer is taken, the SocketSource
owns the attached transformation, and therefore will destroy it. See ownership for more details.
Sources, filters and sinks are discussed at Pipelining. The pipeline article explains the design and shows you how to use them.
Construction
SocketSource (socket_t s=INVALID_SOCKET, bool pumpAll=false, BufferedTransformation *attachment=NULL)
Usage
Example
Missing Data
Its not uncommon to experience Missing Data in a pipeline. A source will send data through a pipeline but have nothing in the sink. This is usually due to the compiler matching the wrong function. For example:
string source = "FF 88 00", destination; StringSink ss(source, new HexDecoder( new StringSink(destination) ) // HexDecoder ); // StringSink
After the above code executes, destination
will likely be empty because the compiler coerces the HexDecoder
(the pointer) to a bool
(the pumpAll
parameter), which leaves the StringSource
's attached transformation NULL
. The compiler will do so without warning, even with -Wall -Wextra -Wconversion
. To resolve the issue, explicitly specify the pumpAll
parameter:
string source = "FF 88 00", destination; StringSink ss(source, true /*pumpAll*/, new HexDecoder( new StringSink(destination) ) // HexDecoder ); // StringSink
Another way data ends up missing is failing to call MessageEnd()
when pumping data. For example, the following may not produce expected results:
// The 4-bit nibble will be buffered waiting for another nibble string source = "FF 88 0", destination; HexDecoder decoder(new StringSink(destination)); decoder.Put(source.data(), source.size()); // Do something with destination
Be sure to call MessageEnd()
when data comes up missing:
string source = "FF 88 0", destination; HexDecoder decoder(new StringSink(destination)); decoder.Put(source.data(), source.size()); decoder.MessageEnd(); // Do something with destination
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