/// <summary>
/// Initializes a new instance of the <see cref="GribFile" /> class. File read rights are shared between processes.
/// </summary>
/// <param name="fileName">Name of the file.</param>
/// <exception cref="System.IO.IOException">Could not open file. See inner exception for more detail.</exception>
/// <exception cref="System.IO.FileLoadException">The file is empty.</exception>
public GribFile(string fileName)
{
FileInfo fi = new FileInfo(fileName);
// need a better check
if (fi.Length < 4)
{
throw new FileLoadException("This file is empty or invalid.");
}
_pFileHandleProxy = GribApiNative.CreateFileHandleProxy(fileName);
if (_pFileHandleProxy == IntPtr.Zero)
{
throw new IOException("Could not open file. See inner exception for more detail.", new Win32Exception(Marshal.GetLastWin32Error()));
}
_fileHandleProxy = (FileHandleProxy)Marshal.PtrToStructure(_pFileHandleProxy, typeof(FileHandleProxy));
FileName = fileName;
Reference = new HandleRef(this, _fileHandleProxy.File);
Context = GribApiProxy.GribContextGetDefault();
// set the message count here; the result seems to be connected to the message iterator so
// that after you begin iterating messages, the count decreases until it reaches 1.
int count = 0;
GribApiProxy.GribCountInFile(Context, this, out count);
MessageCount = count;
}