Split LoreIn/OutputStream

Implemented skip, mark and reset
2026-09-17 06:38:56 +00:00 · 2019-10-11 17:51:07 +02:00
parent 41fac3b08a
commit 6311b9ed15
6 changed files with 180 additions and 115 deletions
@@ -0,0 +1,146 @@
+package com.dre.brewery.lore;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class Base91DecoderStream extends FilterInputStream {
+
+	private static final basE91 DECODER = new basE91();
+
+	private byte[] decbuf = new byte[18];
+	private byte[] buf = new byte[16];
+	private int reader = 0;
+	private int count = 0;
+	private byte[] markBuf = null;
+
+	public Base91DecoderStream(InputStream in) {
+		super(in);
+	}
+
+	private void decode() throws IOException {
+		reader = 0;
+		count = in.read(decbuf);
+		if (count < 1) {
+			count = DECODER.decEnd(buf);
+			if (count < 1) {
+				count = -1;
+			}
+			return;
+		}
+		count = DECODER.decode(decbuf, count, buf);
+	}
+
+	@Override
+	public int read() throws IOException {
+		if (count == -1) return -1;
+		if (count == 0 || reader == count) {
+			decode();
+			return read();
+		}
+		return buf[reader++] & 0xFF;
+	}
+
+	@Override
+	public int read(byte[] b, int off, int len) throws IOException {
+		if (b == null) throw new NullPointerException();
+		if (off < 0 || len < 0 || len > b.length - off) throw new IndexOutOfBoundsException();
+		if (len == 0) return 0;
+
+		if (count == -1) return -1;
+		if (count == 0 || reader == count) {
+			decode();
+			if (count == -1) return -1;
+		}
+
+		if (count > 0 && count - reader >= len) {
+			// enough data in buffer, copy it out directly
+			System.arraycopy(buf, reader, b, off, len);
+			reader += len;
+			return len;
+		}
+
+		int out = 0;
+		int writeSize;
+		while (count > 0) {
+			writeSize = Math.min(len, count - reader);
+			System.arraycopy(buf, reader, b, off + out, writeSize);
+			out += writeSize;
+			len -= writeSize;
+			if (len > 0) {
+				decode();
+			} else {
+				reader += writeSize;
+				break;
+			}
+		}
+		return out;
+	}
+
+	@Override
+	public long skip(long n) throws IOException {
+		if (count == -1) return 0;
+		if (count > 0 && count - reader >= n) {
+			reader += n;
+			return n;
+		}
+		long skipped = count - reader;
+		decode();
+
+		while (count > 0) {
+			if (count > n - skipped) {
+				reader = (int) (n - skipped);
+				return n;
+			}
+			skipped += count;
+			decode();
+		}
+		return skipped;
+	}
+
+	@Override
+	public int available() throws IOException {
+		return Math.round(in.available() * 0.813F); // Ratio encoded to decoded with random data
+	}
+
+	@Override
+	public void close() throws IOException {
+		in.close();
+		count = -1;
+		DECODER.decReset();
+		buf = null;
+		decbuf = null;
+	}
+
+	@Override
+	public synchronized void mark(int readlimit) {
+		if (!markSupported()) return;
+		if (count == -1) return;
+		in.mark(readlimit);
+		DECODER.decMark();
+		if (count > 0 && reader < count) {
+			markBuf = new byte[count - reader];
+			System.arraycopy(buf, reader, markBuf, 0, markBuf.length);
+		} else {
+			markBuf = null;
+		}
+	}
+
+	@Override
+	public synchronized void reset() throws IOException {
+		if (!markSupported()) throw new IOException("mark and reset not supported");
+		in.reset();
+		DECODER.decUnmark();
+		reader = 0;
+		count = 0;
+		if (markBuf != null) {
+			System.arraycopy(markBuf, 0, buf, 0, markBuf.length);
+			count = markBuf.length;
+		}
+	}
+
+	@Override
+	public boolean markSupported() {
+		return in.markSupported();
+	}
+}