README

This code was imported from f-spot in mid-2006, and has been developed some
since then.  No API changes have been made, but some types have been updated
and code is a wee bit cleaner.  There are still some unimplemented features.
Most notably, the Object class has been reworked a bit so that it properly
disposes of unmanaged resources.

The source for f-spot can be found at:
http://ftp.gnome.org/Public/GNOME/sources/f-spot
http://cvs.gnome.org/viewcvs/f-spot/libgphoto2-sharp

Many thanks to Larry Ewing and Ewen Cheslack-Postava for releasing this
code as LGPL so that it can operate with libgphoto2 and other code legally.

IMPORTANT NOTE:

   This is in alpha state, we still have a few things to figure
   out before we can call this interface stable.

TODO:

 * Implement Aaron Bockover's Shamrock m4 macros for mono searching

 * Define special binding macros like the camlib or iolib macros, perhaps
   even define a generic set of macros for all three.

BUILDING:

  * If you are using source code from git, run "autoreconf -is".
  * configure
  * make
  * make install


NOTE FOR 64BIT USERS:
The binding currently does not support 64bit windows systems due to limitations
in the libgphoto2 api. They expose 'long' types in their public API, which
change from 32bit length to 64bit length based on both platform and the
compiler used. There are currently three ways to work around this issue. I
have listed them in order of how easy they are to complete:

1) Alter the libgphoto2 API to expose the standard types such as int64_t
and int32_t in place of the 'long' type which will give a guaranteed
sized variable. This can be easily P/Invoked from C# (and Java). This
would involve changing approximately a dozen places in code from 'long'
to 'int64_t'.

2) Write a glue wrapper in C which replicates the functions and structs
which expose 'long' types and replace the 'long' with int32_t or int64_t
and then P/Invoke the wrapper instead of the actual libgphoto2 API. The
wrapper will be in control of converting from the libgphoto2 struct
to the wrapper struct which will be the one returned to C#.

3) Replicate the strutures and methods in C# to have ones that work
with a 32bit long and 64bit long platform. Use runtime detection to
decide what platform your on and then call the correct P/Invoke method.
If you're on a 64bit platform, you'll then have to convert the 64bit struct
to a 32bit struct and then return that. An example of this is done below.
This method is *not* recommended.


//FIXME: This is a nasty hack to make the library work on 32bit
// and 64bit systems.
[StructLayout (LayoutKind.Sequential)]
public struct CameraStorageInformation
{
	public CameraStorageInfoFields fields;
	[MarshalAs (UnmanagedType.ByValTStr, SizeConst=256)] public string basedir;
	[MarshalAs (UnmanagedType.ByValTStr, SizeConst=256)] public string label;
	[MarshalAs (UnmanagedType.ByValTStr, SizeConst=256)] public string description;
	public CameraStorageType type;
	public CameraStorageFilesystemType fstype;
	public CameraStorageAccessType access;
	public uint capacitykbytes;
	public uint freekbytes;
	public uint freeimages;
}

[StructLayout (LayoutKind.Sequential)]
public struct CameraStorageInformation64
{
	public CameraStorageInfoFields fields;
	[MarshalAs (UnmanagedType.ByValTStr, SizeConst=256)] public string basedir;
	[MarshalAs (UnmanagedType.ByValTStr, SizeConst=256)] public string label;
	[MarshalAs (UnmanagedType.ByValTStr, SizeConst=256)] public string description;
	public CameraStorageType type;
	public CameraStorageFilesystemType fstype;
	public CameraStorageAccessType access;
	public long capacitykbytes;
	public long freekbytes;
	public long freeimages;
}
	

	
public CameraStorageInformation[] GetStorageInformation (Context context)
{
	if (IntPtr.Size == 4)
	{
		Console.WriteLine("Using 64bit method");
		return Get64BitStorageInformation(context);
	}
	else
	{
		Console.WriteLine("Using 32bit method");
		return Get32BitStorageInformation(context);
	}
}
	
private CameraStorageInformation[] Get64BitStorageInformation(Context context)
{
	int num = 0;	
	IntPtr p = new IntPtr();
	
	Error.CheckError(gp_camera_get_storageinfo (this.Handle, ref p, ref num, context.Handle));
	
	CameraStorageInformation64[] info_structs = new CameraStorageInformation64[num];
	for (int i = 0; i < num; i++) {
		IntPtr ptrStruct = new IntPtr(p.ToInt64() + Marshal.SizeOf(typeof(CameraStorageInformation64)) * i);
		info_structs[i] = (CameraStorageInformation64)Marshal.PtrToStructure(ptrStruct, typeof(CameraStorageInformation64) );
	}
		
	CameraStorageInformation[] structs = new CameraStorageInformation[info_structs.Length];
	for(int i=0; i < info_structs.Length; i++)
	{
		structs[i].access = info_structs[i].access;
		structs[i].basedir = info_structs[i].basedir;
		structs[i].capacitykbytes = (uint)info_structs[i].capacitykbytes;
		structs[i].description = info_structs[i].description;
		structs[i].fields = info_structs[i].fields;
		structs[i].freeimages = (uint)info_structs[i].freeimages;
		structs[i].freekbytes = (uint)info_structs[i].freekbytes;
		structs[i].fstype = info_structs[i].fstype;
		structs[i].label = info_structs[i].label;
		structs[i].type = info_structs[i].type;
	}
		// Free the unmanaged array
		Marshal.FreeHGlobal(p);
		return structs;
}
	
private CameraStorageInformation[] Get32BitStorageInformation(Context context)
{
	int num = 0;	
	IntPtr p = new IntPtr();
		
	Error.CheckError(gp_camera_get_storageinfo (this.Handle, ref p, ref num, context.Handle));
		
	CameraStorageInformation[] info_structs = new CameraStorageInformation[num];
	for (int i = 0; i < num; i++) {
		IntPtr ptrStruct = new IntPtr(p.ToInt64() + Marshal.SizeOf(typeof(CameraStorageInformation)) * i);
		info_structs[i] = (CameraStorageInformation)Marshal.PtrToStructure(ptrStruct, typeof(CameraStorageInformation) );
	}
	
	// Free the unmanaged array
	Marshal.FreeHGlobal(p);
	return info_structs;
}