/*  
 *  $Id$
 *
 *                              
 *                    L O S  A L A M O S
 *              Los Alamos National Laboratory
 *               Los Alamos, New Mexico 87545
 *                                  
 *  Copyright, 1986, The Regents of the University of California.
 *                                  
 *           
 *	Author Jeffrey O. Hill
 *	johill@lanl.gov
 */

#define epicsAssertAuthor "Jeff Hill johill@lanl.gov"

#include "iocinf.h"
#include "virtualCircuit.h"

comQueRecv::comQueRecv ()
{
}

comQueRecv::~comQueRecv ()
{
    this->clear ();
}

void comQueRecv::clear ()
{
    comBuf *pBuf;

    while ( ( pBuf = this->bufs.get () ) ) {
        pBuf->destroy ();
    }
}

unsigned comQueRecv::occupiedBytes () const
{
    unsigned count = this->bufs.count ();
    unsigned nBytes;

    if ( count == 0u ) {
        nBytes = 0u;
    }
    else if ( count == 1u ) {
        nBytes = this->bufs.first ()->occupiedBytes ();
    }
    else {
        // this requires the compress operation in 
        // copyIn ( comBuf & bufIn )
        nBytes = this->bufs.first ()->occupiedBytes ();
        nBytes += this->bufs.last ()->occupiedBytes ();
        nBytes += ( count - 2u ) * comBuf::capacityBytes ();
    }

    return nBytes;
}

unsigned comQueRecv::copyOutBytes ( void *pBuf, unsigned nBytes )
{
    char *pCharBuf = static_cast < char * > ( pBuf );

    unsigned totalBytes = 0u;
    do {
        comBuf * pComBuf = this->bufs.first ();
        if ( ! pComBuf ) {
            return totalBytes;
        }
        totalBytes += pComBuf->copyOutBytes ( &pCharBuf[totalBytes], nBytes - totalBytes );
        if ( pComBuf->occupiedBytes () == 0u ) {
            this->bufs.remove ( *pComBuf );
            pComBuf->destroy ();
        }
    }
    while ( totalBytes < nBytes );
    return totalBytes;
}

unsigned comQueRecv::removeBytes ( unsigned nBytes )
{
    unsigned totalBytes = 0u;
    unsigned bytesLeft = nBytes;
    while ( bytesLeft ) {
        comBuf * pComBuf = this->bufs.first ();
        if ( ! pComBuf ) {
            return totalBytes;
        }
        unsigned nBytesThisTime = pComBuf->removeBytes ( bytesLeft );
        if ( pComBuf->occupiedBytes () == 0u ) {
            this->bufs.remove ( *pComBuf );
            pComBuf->destroy ();
        }
        if ( nBytesThisTime == 0u) {
            break;
        }
        totalBytes += nBytesThisTime;
        bytesLeft = nBytes - totalBytes;
    }
    return totalBytes;
}

void comQueRecv::pushLastComBufReceived ( comBuf & bufIn )
{
    comBuf *pLastBuf = this->bufs.last ();
    if ( pLastBuf ) {
        pLastBuf->copyIn ( bufIn );
    }
    if ( bufIn.occupiedBytes () ) {
        // move occupied bytes to the start of the buffer
        bufIn.compress ();
        this->bufs.add ( bufIn );
    }
    else {
        bufIn.destroy ();
    }
}

epicsUInt8 comQueRecv::popUInt8 ()
{
    comBuf *pComBuf = this->bufs.first ();
    if ( pComBuf ) {
        epicsUInt8 tmp = pComBuf->getByte ();
        if ( pComBuf->occupiedBytes() == 0u ) {
            this->bufs.remove ( *pComBuf );
            pComBuf->destroy ();
        }
        return tmp;
    }
    throw insufficentBytesAvailable ();
}