#ifndef _DATASOURCE_H_
#define _DATASOURCE_H_

#ifdef __cplusplus
extern "C" {
#endif

  /* open a virtual file for read, return the ID for the virtual file */
  int sopen_rd();

  /* open a virtual file for write, return the ID for the virtual file */ 
  int sopen_wt();

  /* 
	 read n bytes from virtual file ID and store them in buf
	 buf must be allocated enough space for n bytes 
     return number of bytes read
  */
  int sread( void* buf, int n, int ID );

  /* 
	 write n bytes from buf to file ID 
	 return number of bytes written
  */
  int swrite( void* buf, int n, int ID );


#ifdef __cplusplus
}
#endif



#endif