kdu_compressed_source::get_pos

Returns the location of the next byte to be read, relative to the current seek origin.

For non-caching sources, the seek origin is the start of the code-stream, regardless of whether or not the code-stream appears at the start of its containing file.

For sources supporting KDU_SOURCE_CAP_CACHED, the seek origin is the start of the code-stream only until such point as the first call to set_precinct_scope or set_tile_header_scope is called. After that, the seek origin is the first byte of the relevant precinct or tile-header (excluding the SOT marker segment).

Non-seekable sources may return a negative value to indicate that the position is not known; seekable sources, however, must implement this function correctly.