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/************************************************************
 *
 *  FUNCTION: ApptChangeRecord
 *
 *  DESCRIPTION: Change a record in the Appointment Database
 *
 *  PARAMETERS: database pointer
 * database index
 * database record
 * changed fields
 *
 *  RETURNS: ##0 if successful, errorcode if not
 *
 *  CREATED: 1/25/95 
 *
 *  BY: Roger Flores
 *
 *COMMENTS:Records are not stored with extra padding - they
 *are always resized to their exact storage space.  This avoids
 *a database compression issue.  The code works as follows:
 *
 *1)get the size of the new record
 *2)make the new record
 *3)pack the packed record plus the changes into the new record
 *4)if the sort position is changes move to the new position
 *5)attach in position
 *
 *************************************************************/
Err ApptChangeRecord(DmOpenRef dbP, UInt16 *index, ApptDBRecordPtr r, 
		     ApptDBRecordFlags changedFields)
{
  Err result;
  Int16 newIndex;
  UInt16 attributes;
  Boolean dontMove;
  MemHandle oldH;
  MemHandle srcH;
  MemHandle dstH;
  ApptDBRecordType src;
  ApptPackedDBRecordPtr dst;
  ApptPackedDBRecordPtr cmp;
  
  // We do not assume that r is completely valid so we get a valid
  // ApptDBRecordPtr...
  if ((result = ApptGetRecord(dbP, *index, &src, &srcH)) != 0)
    return result;
  
  // and we apply the changes to it.
  if (changedFields.when) 
    src.when = r->when;
  
  if (changedFields.alarm) 
    src.alarm = r->alarm;
  
  if (changedFields.repeat)
    src.repeat = r->repeat;
  
  if (changedFields.exceptions)
    src.exceptions = r->exceptions;
  
  if (changedFields.description)
    src.description = r->description;
  
  if (changedFields.note)
    src.note = r->note;


  // Allocate a new chunk with the correct size and pack the data from 
  // the unpacked record into it.
  dstH = DmNewHandle(dbP, (UInt32) ApptPackedSize(&src));
  if (dstH)
    {
      dst = MemHandleLock (dstH);
      ApptPack (&src, dst);
    }

  MemHandleUnlock (srcH);
  if (dstH == NULL)
    return dmErrMemError;


  // If the sort position is changed move to the new position.
  // Check if any of the key fields have changed. 
  if ((!changedFields.when) && (! changedFields.repeat))
    goto attachRecord;// repeating events aren't in sorted order
  
  
  // Make sure *index-1 < *index < *index+1, if so it's in sorted 
  // order.  Leave it there.
  if (*index > 0)
    {
      // This record wasn't deleted and deleted records are at the end of the
      // database so the prior record may not be deleted!
      cmp = MemHandleLock (DmQueryRecord(dbP, *index-1));
      dontMove = (ApptComparePackedRecords (cmp, dst, 0, NULL, NULL, 0) <= 0);
      MemPtrUnlock (cmp);
    }
  else 
    dontMove = true;


  if (dontMove && (*index+1 < DmNumRecords (dbP)))
    {
      DmRecordInfo(dbP, *index+1, &attributes, NULL, NULL);
      if ( ! (attributes & dmRecAttrDelete) )
	{
	  cmp = MemHandleLock (DmQueryRecord(dbP, *index+1));
	  dontMove = dontMove && ApptComparePackedRecords (dst, cmp, 0, NULL, NULL, 0) <= 0;
	  MemPtrUnlock (cmp);
	}
    }
  
  if (dontMove)
    goto attachRecord;
  
  
  // The record isn't in the right position.  Move it.
  newIndex = ApptFindSortPosition (dbP, dst);
  DmMoveRecord (dbP, *index, newIndex);
  if (newIndex > *index) newIndex--;
  *index = newIndex;// return new position


 attachRecord:
  // Attach the new record to the old index,  the preserves the 
  // category and record id.
  result = DmAttachRecord (dbP, index, dstH, &oldH);
  
  MemPtrUnlock(dst);

  if (result) return result;

  MemHandleFree(oldH);

#ifEMULATION_LEVEL != EMULATION_NONE
  ECApptDBValidate (dbP);
  #endif

  return 0;
}


/************************************************************
 *
 *  FUNCTION: ApptNewRecord
 *
 *  DESCRIPTION: Create a new packed record in sorted position
 *
 *  PARAMETERS: database pointer
 *database record
 *
 *  RETURNS: ##0 if successful, error code if not
 *
 *  CREATED: 1/25/95 
 *
 *  BY: Roger Flores
 *
 *************************************************************/
Err ApptNewRecord(DmOpenRef dbP, ApptDBRecordPtr r, UInt16 *index)
{
  MemHandle recordH;
  ApptPackedDBRecordPtr recordP;
  UInt16 newIndex;
  Err err;

  
  // Make a new chunk with the correct size.
  recordH = DmNewHandle (dbP, (UInt32) ApptPackedSize(r));
  if (recordH == NULL)
    return dmErrMemError;

  recordP = MemHandleLock (recordH);
  
  // Copy the data from the unpacked record to the packed one.
  ApptPack (r, recordP);

  newIndex = ApptFindSortPosition(dbP, recordP);

  MemPtrUnlock (recordP);

  // 4) attach in place
  err = DmAttachRecord(dbP, &newIndex, recordH, 0);
  if (err) 
    MemHandleFree(recordH);
  else
    *index = newIndex;
  
  return err;
}



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Chirico img Mike Chirico, a father of triplets (all girls) lives outside of Philadelphia, PA, USA. He has worked with Linux since 1996, has a Masters in Computer Science and Mathematics from Villanova University, and has worked in computer-related jobs from Wall Street to the University of Pennsylvania. His hero is Paul Erdos, a brilliant number theorist who was known for his open collaboration with others.


Mike's notes page is souptonuts. For open source consulting needs, please send an email to mchirico@gmail.com. All consulting work must include a donation to SourceForge.net.

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