---

CNSCLOutputBuffer.cpp

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/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 2, June 1991

 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
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 Everyone is permitted to copy and distribute verbatim copies
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*/
static const char* Copyright = "(C) Copyright Michigan State University 2002, All rights reserved";


#include "CNSCLOutputBuffer.h"                  
#include <string>
#include <unistd.h>
#include <CRangeError.h>

// Manifest constants:

static const int hdrWSIZE = 0;  // Offset to size in header (Word).
static const int hdrWTYPE = 1;  // Offset to Type field of header (Word).
static const int hdrWCKS  = 2;  // Offset to checksum field of header (Word).
static const int hdrWRUN  = 3;  // Offset to run number of header (Word).
static const int hdrLSEQ  = 4;  // Offset to sequence number in header.
static const int hdrWENTITY = 6; // Offset to entity count.
static const int hdrWUNUSED1 = 7; // Decomissioned lam mask field.
static const int hdrWCPU  = 8;  // CPU identifier.
static const int hdrWUNUSED2 = 9; // Decomisioned bitregister count.
static const int hdrWBUFFMT = 10; // Buffer format indicator.
static const int hdrWSIG   = 11; // Short signature.
static const int hdrLSIG   = 12; // Long signature.
static const int hdrWUNUSED3 =14; // 14,15, are both unused.
static const int BODYOFFSET = 16;

static const short SSIGNATURE = 0x0102;
static const long  LSIGNATURE = 0x01020304;

static const short REVLEVEL = 5; // lvl 5 - removes unused header items.

// Static class members.


unsigned long CNSCLOutputBuffer::m_nSequence = 0; //Static data member initialization

int CNSCLOutputBuffer::m_ControlTag = 3;
int CNSCLOutputBuffer::m_EventTag   = 2;

//Default constructor alternative to compiler provided default constructor
//Association object data member pointers initialized to null association object 
CNSCLOutputBuffer::CNSCLOutputBuffer (unsigned nWords)
   : m_Buffer(nWords),   m_BufferPtr(&m_Buffer),   m_nWords(nWords) 
{
  InitializeHeader();
} 

// Functions for class CNSCLOutputBuffer

void 
CNSCLOutputBuffer::ComputeSize()  
{
  m_Buffer[hdrWSIZE] = m_BufferPtr.GetIndex();
}  

void 
CNSCLOutputBuffer::SetType(int nType)  
{
  m_Buffer[hdrWTYPE] = nType;
}  

void 
CNSCLOutputBuffer::ComputeChecksum()  
{
  m_Buffer[hdrWCKS] = 0;        // Don't let old cks contribute if set.
  int nWords = m_Buffer[hdrWSIZE];
  short cks(0);

  DAQWordBufferPtr p(&m_Buffer); // Pointer iteration much better than idx.
  for(int i = 0; i < nWords; i++) {
    cks += *p;
    ++p;                        // Pre increment faster than post.
  }
  m_Buffer[hdrWCKS] = - cks;    // Buffer will now checksum to zero.
}  

DAQWordBufferPtr 
CNSCLOutputBuffer::StartEntity()  
{
  return m_BufferPtr;
}

void 
CNSCLOutputBuffer::EndEntity(const DAQWordBufferPtr& rpBuf)  
{
  m_BufferPtr = rpBuf;          // Update internal cursor.
  m_Buffer[hdrWENTITY]++;       // And the entity count.
}  

void 
CNSCLOutputBuffer::SetCpuNum(unsigned short nValue)  
{
  if(nValue) {
    m_Buffer[hdrWCPU] = nValue;
  }
  else {
    m_Buffer[hdrWCPU] = (short)(gethostid() & 0xffff);
  }
}  

void 
CNSCLOutputBuffer::SetNbitRegisters(unsigned  nBitReg=1)  
{
  m_Buffer[hdrWUNUSED2] = nBitReg;
}  

void 
CNSCLOutputBuffer::SetLamRegisters(unsigned short nLams=0)  
{
  m_Buffer[hdrWUNUSED1] = nLams;
}  

void 
CNSCLOutputBuffer::PutEntity(void* pEntity, unsigned int nWords)  
{
  DAQWordBufferPtr p = StartEntity();
  unsigned short*  s = (unsigned short*)pEntity;

  while(nWords) {
    *p = *s++;
    ++p;
    nWords--;
  }
  EndEntity(p);
 
}  

void 
CNSCLOutputBuffer::PutLong(const unsigned long& rLong)  
{
  union {
    unsigned long l;
    unsigned short w[2];
  } d;
  d.l = rLong;

  *m_BufferPtr = d.w[0];
  ++m_BufferPtr;
  *m_BufferPtr = d.w[1];
  ++m_BufferPtr;
}  

void 
CNSCLOutputBuffer::PutWord(unsigned short nData)  
{
  *m_BufferPtr = nData;
  ++m_BufferPtr;
}  

void 
CNSCLOutputBuffer::PutWords(const unsigned short* pWords, unsigned int nWords)  
{
  while(nWords) {
    *m_BufferPtr = *pWords++;
    ++m_BufferPtr;
    nWords--;
  }
}  

void 
CNSCLOutputBuffer::PutString(const char*  pData, int nMaxSize=-1)  
{
  string data(pData);

  // The following code is required if nMaxSize is supplied:

  if(nMaxSize > 0) {
    if(nMaxSize & 1) nMaxSize++; // nMaxSize must be even.

    if(data.size() < (nMaxSize - 1)) { // Allow for null terminator.
      int nPad = (nMaxSize-1) - data.size(); // Pad count.
      while(nPad) {
        data+= ' ';
        nPad--;
      }
    }
  }
  // If the string is an even number of bytes it must be padded by one
  // ' '.  Note that if nMaxSize was supplied, the string is already
  // correctly sized as an odd.
  //
  if(!(data.size() & 1)) {
    data += ' ';
  }

  // Now the string 'data' contains the exact number of 'functional'
  // characters to put in the buffer... and that number is odd.
  // We need to put all but the last character in the buffer a word
  // (two characters) at a time.
  // 
  union {
    char c[2];
    unsigned short w;
  } d;                          // Ensure endianness is not an issue.
  int nChars = data.size();
  int i;                        // Want loop index after loop.
  for(i = 0; i < nChars - 1; i+=2) {
    d.c[0] = data[i];
    d.c[1] = data[i+1];
    *m_BufferPtr = d.w;
    ++m_BufferPtr;
  }
  // Now take care of the last character which is put along with
  // a terminating null.  This is why we wanted the loop index above
  // to stay in scope.
  d.c[0] = data[i];
  d.c[1] = '\0';
  *m_BufferPtr = d.w;
  ++m_BufferPtr;
}  

void 
CNSCLOutputBuffer::SetRun(unsigned short nRun)  
{
  m_Buffer[hdrWRUN] = nRun;
}  

bool 
CNSCLOutputBuffer::EntityFits(unsigned short  nWords)  
{
  int nOffset = m_BufferPtr.GetIndex();
  nOffset += nWords;            // Here's where the next entity would start.
  return (nOffset <= m_nWords);
}  

void 
CNSCLOutputBuffer::Route(bool NextSequence)  
{
  ComputeSize();
  ComputeChecksum();
  m_Buffer.Route();
  if(NextSequence) IncrementSequence();
  m_Buffer.Resize(m_nWords, true);
  InitializeHeader();
}  

void 
CNSCLOutputBuffer::Seek(int nOffset, int  whence=SEEK_SET)  
{
  int nAbsOff;
  switch(whence) {
  case SEEK_SET: {              // Absolute seek:
    nAbsOff = nOffset;
  }
  break;
  case SEEK_CUR: {
    nAbsOff = m_BufferPtr.GetIndex() + nOffset;
  }
  break;
  case SEEK_END: {
    nAbsOff = (m_nWords - 1) + nOffset;
  }
  break;
  default:
    throw CRangeError(SEEK_SET, SEEK_END, whence,
                      " CNSCLOUTPUTBuffer::seek- Invalid location for whence");
    return;
  }
  // If control passes here, nAbsOff has the absolute offset desired.
  
  DAQWordBufferPtr p(&m_Buffer);
  p += nAbsOff;
  
  m_BufferPtr = p;
}  

void 
CNSCLOutputBuffer::IncrementSequence()
{
  m_nSequence++;
}  

void 
CNSCLOutputBuffer::ClearSequence()  
{
   m_nSequence = 0;
}
void
CNSCLOutputBuffer::InitializeHeader()
{
  union {
    long l;
    short w[2];
  } longbuffer;

  m_BufferPtr         += BODYOFFSET;

  // Initialize the header to known and where possible sensible
  // initial values:

  m_Buffer[hdrWSIZE]   = 0;
  m_Buffer[hdrWTYPE]   = 0;
  m_Buffer[hdrWCKS]    = 0;
  longbuffer.l         = m_nSequence;
  m_Buffer[hdrLSEQ]    = longbuffer.w[0];
  m_Buffer[hdrLSEQ+1]  = longbuffer.w[1];
  m_Buffer[hdrWENTITY] = 0;
  m_Buffer[hdrWUNUSED1]= 0;
  m_Buffer[hdrWBUFFMT] = REVLEVEL;
  m_Buffer[hdrWSIG]    = SSIGNATURE;
  longbuffer.l         = LSIGNATURE;
  m_Buffer[hdrLSIG]    = longbuffer.w[0];
  m_Buffer[hdrLSIG+1]  = longbuffer.w[1];

  // Zero the unused fields of the header only.

  m_Buffer[hdrWUNUSED1] = 0;  
  m_Buffer[hdrWUNUSED2] = 0;
  m_Buffer[hdrWUNUSED3] = 0;
  m_Buffer[hdrWUNUSED3+1] = 0;


}
unsigned short
CNSCLOutputBuffer::getEntityCount()
{
  return m_Buffer[hdrWENTITY];
}
void
CNSCLOutputBuffer::Resize(int newsize)
{
   m_Buffer.Resize(newsize, true);              // Wait for resize to finish.
}

---