const func bigInteger: bigLength (ref null_file: aFile)

Obtain the length of a file. A null_file is not seekable, therefore FILE_ERROR is raised. Derived types of null_file need to override this function.

Returns:

nothing, because FILE_ERROR is always raised.

Raises:

FILE_ERROR - Is always raised, because a null_file is not seekable.

const proc: seek (ref null_file: aFile, ref bigInteger: position)

Set the current file position. A null_file is not seekable, therefore FILE_ERROR is raised. If a derived type is seekable it needs to override this function.

Raises:

FILE_ERROR - Is always raised, because a null_file is not seekable.

const func bigInteger: bigTell (ref null_file: aFile)

Obtain the current file position. A null_file is not seekable, therefore FILE_ERROR is raised. If a derived type is seekable it needs to override this function.

Returns:

nothing, because FILE_ERROR is always raised.

Raises:

FILE_ERROR - Is always raised, because a null_file is not seekable.

const func bigInteger: bigLength (ref external_file: aFile)

Determine the size of a file and return it as bigInteger. The file length is measured in bytes.

Returns:

the size of the given file.

Raises:

FILE_ERROR - A system function returns an error or the file length reported by the system is negative.

MEMORY_ERROR - Not enough memory to represent the result.

const proc: seek (ref external_file: aFile, in bigInteger: position)

Set the current file position. The file position is measured in bytes from the start of the file. The first byte in the file has the position 1.

Raises:

RANGE_ERROR - The file position is negative or zero or the file position is not representable in the system file position type.

FILE_ERROR - A system function returns an error.

const func bigInteger: bigTell (ref external_file: aFile)

Obtain the current file position. The file position is measured in bytes from the start of the file. The first byte in the file has the position 1.

Returns:

the current file position.

Raises:

FILE_ERROR - A system function returns an error or the file position reported by the system is negative.

MEMORY_ERROR - Not enough memory to represent the result.