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// --------------------------------------------------------------------------
//
// File
// Name: ProtocolUncertainStream.h
// Purpose: Read part of another stream
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
#include "Box.h"
#include "autogen_ConnectionException.h"
#include "autogen_ServerException.h"
#include "ProtocolUncertainStream.h"
#include "Protocol.h"
#include "MemLeakFindOn.h"
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::ProtocolUncertainStream(IOStream &, int)
// Purpose: Constructor, taking another stream.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
ProtocolUncertainStream::ProtocolUncertainStream(IOStream &rSource)
: mrSource(rSource),
mBytesLeftInCurrentBlock(0),
mFinished(false)
{
}
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::~ProtocolUncertainStream()
// Purpose: Destructor. Won't absorb any unread bytes.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
ProtocolUncertainStream::~ProtocolUncertainStream()
{
if(!mFinished)
{
BOX_WARNING("ProtocolUncertainStream destroyed before "
"stream finished");
}
}
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::Read(void *, int, int)
// Purpose: As interface.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
int ProtocolUncertainStream::Read(void *pBuffer, int NBytes, int Timeout)
{
// Finished?
if(mFinished)
{
return 0;
}
int read = 0;
while(read < NBytes)
{
// Anything we can get from the current block?
ASSERT(mBytesLeftInCurrentBlock >= 0);
if(mBytesLeftInCurrentBlock > 0)
{
// Yes, let's use some of these up
int toRead = (NBytes - read);
if(toRead > mBytesLeftInCurrentBlock)
{
// Adjust downwards to only read stuff out of the current block
toRead = mBytesLeftInCurrentBlock;
}
BOX_TRACE("Reading " << toRead << " bytes from stream");
// Read it
int r = mrSource.Read(((uint8_t*)pBuffer) + read, toRead, Timeout);
// Give up now if it didn't return anything
if(r == 0)
{
BOX_TRACE("Read " << r << " bytes from "
"stream, returning");
return read;
}
// Adjust counts of bytes by the bytes recieved
read += r;
mBytesLeftInCurrentBlock -= r;
// stop now if the stream returned less than we asked for -- avoid blocking
if(r != toRead)
{
BOX_TRACE("Read " << r << " bytes from "
"stream, returning");
return read;
}
}
else
{
// Read the header byte to find out how much there is
// in the next block
uint8_t header;
if(mrSource.Read(&header, 1, Timeout) == 0)
{
// Didn't get the byte, return now
BOX_TRACE("Read 0 bytes of block header, "
"returning with " << read << " bytes "
"read this time");
return read;
}
// Interpret the byte...
if(header == Protocol::ProtocolStreamHeader_EndOfStream)
{
// All done.
mFinished = true;
BOX_TRACE("Stream finished, returning with " <<
read << " bytes read this time");
return read;
}
else if(header <= Protocol::ProtocolStreamHeader_MaxEncodedSizeValue)
{
// get size of the block from the Protocol's lovely list
mBytesLeftInCurrentBlock = Protocol::sProtocolStreamHeaderLengths[header];
}
else if(header == Protocol::ProtocolStreamHeader_SizeIs64k)
{
// 64k
mBytesLeftInCurrentBlock = (64*1024);
}
else
{
// Bad. It used the reserved values.
THROW_EXCEPTION(ServerException, ProtocolUncertainStreamBadBlockHeader)
}
BOX_TRACE("Read header byte " << (int)header << ", "
"next block has " <<
mBytesLeftInCurrentBlock << " bytes");
}
}
// Return the number read
return read;
}
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::BytesLeftToRead()
// Purpose: As interface.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
IOStream::pos_type ProtocolUncertainStream::BytesLeftToRead()
{
// Only know how much is left if everything is finished
return mFinished?(0):(IOStream::SizeOfStreamUnknown);
}
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::Write(const void *, int)
// Purpose: As interface. But will exception.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
void ProtocolUncertainStream::Write(const void *pBuffer, int NBytes, int Timeout)
{
THROW_EXCEPTION(ServerException, CantWriteToProtocolUncertainStream)
}
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::StreamDataLeft()
// Purpose: As interface.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
bool ProtocolUncertainStream::StreamDataLeft()
{
return !mFinished;
}
// --------------------------------------------------------------------------
//
// Function
// Name: ProtocolUncertainStream::StreamClosed()
// Purpose: As interface.
// Created: 2003/12/05
//
// --------------------------------------------------------------------------
bool ProtocolUncertainStream::StreamClosed()
{
// always closed
return true;
}
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