Io_buffer_rdr.java

/*
XOWA: the XOWA Offline Wiki Application
Copyright (C) 2012-2017 gnosygnu@gmail.com

XOWA is licensed under the terms of the General Public License (GPL) Version 3,
or alternatively under the terms of the Apache License Version 2.0.

You may use XOWA according to either of these licenses as is most appropriate
for your project on a case-by-case basis.

The terms of each license can be found in the source code repository:

GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
*/
package gplx.core.ios; import gplx.*; import gplx.core.*;
import gplx.core.ios.streams.*;/*IoStream*/
public class Io_buffer_rdr implements Rls_able {
	private Io_stream_rdr rdr;
	Io_buffer_rdr(Io_stream_rdr rdr, Io_url url, int bfr_len) {
		this.rdr = rdr; this.url = url;
		if (bfr_len <= 0) throw Err_.new_wo_type("bfr_len must be > 0", "bfr_len", bfr_len);
		bfr = new byte[bfr_len]; this.bfr_len = bfr_len;
		IoItmFil fil = Io_mgr.Instance.QueryFil(url); if (!fil.Exists()) throw Err_.new_wo_type("fil does not exist", "url", url);
		fil_len = fil.Size();
		fil_pos = 0;
		fil_eof = false;
	}
	public Io_url Url() {return url;} private Io_url url;
	public byte[] Bfr() {return bfr;} private byte[] bfr;
	public int Bfr_len() {return bfr_len;} private int bfr_len;
	public long Fil_len() {return fil_len;} long fil_len;
	public long Fil_pos() {return fil_pos;} long fil_pos;
	public boolean Fil_eof() {return fil_eof;} private boolean fil_eof;
	public boolean Bfr_load_all() {return Bfr_load(0, bfr_len);}
	public boolean Bfr_load_from(int bfr_pos) {
		if (bfr_pos < 0 || bfr_pos > bfr_len) throw Err_.new_wo_type("invalid bfr_pos", "bfr_pos", bfr_pos, "bfr_len", bfr_len);
		for (int i = bfr_pos; i < bfr_len; i++)				// shift end of bfr to bgn; EX: bfr[10] and load_from(8); [8] -> [0]; [9] -> [1];
			bfr[i - bfr_pos] = bfr[i];
		return Bfr_load(bfr_len - bfr_pos, bfr_pos);		// fill rest of bfr; EX: [2]... will come from file
	}
	private boolean Bfr_load(int bgn, int len) {
		int read = rdr.Read(bfr, bgn, len);
		if (read == gplx.core.ios.streams.Io_stream_rdr_.Read_done) {fil_eof = true; return false;}
		fil_pos += read;
		bfr_len = bgn + read;
		if (read < len) fil_eof = true;
		return true;
	}
	public void Seek(long fil_pos) {
		this.fil_pos = fil_pos;
		rdr.Skip(fil_pos);
		this.Bfr_load_all();
	}
	public void Rls() {
		bfr = null;
		bfr_len = -1;
		if (rdr != null) rdr.Rls();
	}
	@gplx.Internal protected void Dump_to_file(int bgn, int len, String url_str, String msg) {	// DBG:
		String text = String_.new_u8__by_len(bfr, bgn, len);
		Io_mgr.Instance.AppendFilStr(Io_url_.new_any_(url_str), msg + text + "\n");
	}
	public static Io_buffer_rdr new_(Io_stream_rdr rdr, int bfr_len) {
		Io_buffer_rdr rv = new Io_buffer_rdr(rdr, rdr.Url(), bfr_len);
		rdr.Open();
		rv.Bfr_load(0, bfr_len);
		return rv;
	}
	public static final    Io_buffer_rdr Null = new Io_buffer_rdr(); Io_buffer_rdr() {}
}