ns_GetAnalogData

 ns_GetAnalogData   Retrieves analog data by index

    Usage:
       [ns_RESULT, ContCount, Data] =  
                ns_GetAnalogData(hFile, EntityID, StartIndex, IndexCount)

    Description:
        Returns the data values associated with the Analog Entity indexed
        EntityID in the file referenced by hFile.  The index of the first
        data value is StartIndex and the requested number of data samples
        is given by IndexCount.  The requested data values are returned
        in the variable Data. 
        Although the samples in an analog entity are indexed, they are not
        guaranteed to be continuous in time and may contain gaps between
        some of the indexes.  When the requested data is returned,
        ContCount contains the number of continuous data points present
        in the data (starting at StartIndex).
        If the index range specified by StartIndex and IndexCount contains
        invalid indexes, the function will return ns_BADINDEX.

    Parameters:
        hFile           Handle/Indentification number to an open file.
        EntityID        Identification number of the Analog Entity in the
                        data file.
        StartIndex      Starting index number of the analog data item.
        IndexCount      Number of analog values to retrieve.

    Return Values:
        ContCount       Number of continuous data values starting with
                        StartIndex.  This field is ignored if the pointer
                        is set to NULL.
        Data            Array of double precision values to receive the
                        analog data.
        ns_RESULT   This function returns ns_OK if the file is successfully
                    opened. Otherwise one of the following error codes is 
                    generated:

                        ns_BADENTITY    Invalid or inappropriate entity 
                                        identifier specified
                        ns_BADINDEX     Invalid entity index or range 
                                        specified
                        ns_FILEERROR    File access or read error

    Copyright (C) 2003 Neuroshare Project
    Author: Almut Branner
    Last modification: 6/20/2003