Mercurial > hg4j
diff src/com/tmate/hgkit/fs/ByteArrayDataAccess.java @ 51:9429c7bd1920 wrap-data-access
Try DataAccess to reach revision data instead of plain byte arrays
author | Artem Tikhomirov <tikhomirov.artem@gmail.com> |
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date | Sun, 16 Jan 2011 01:20:26 +0100 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/com/tmate/hgkit/fs/ByteArrayDataAccess.java Sun Jan 16 01:20:26 2011 +0100 @@ -0,0 +1,74 @@ +/* + * Copyright (c) 2011 Artem Tikhomirov + */ +package com.tmate.hgkit.fs; + +import java.io.IOException; + +/** + * + * @author artem + */ +public class ByteArrayDataAccess extends DataAccess { + + private final byte[] data; + private final int offset; + private final int length; + private int pos; + + public ByteArrayDataAccess(byte[] data) { + this(data, 0, data.length); + } + + public ByteArrayDataAccess(byte[] data, int offset, int length) { + this.data = data; + this.offset = offset; + this.length = length; + pos = 0; + } + + @Override + public byte readByte() throws IOException { + if (pos >= length) { + throw new IOException(); + } + return data[offset + pos++]; + } + @Override + public void readBytes(byte[] buf, int off, int len) throws IOException { + if (len > (this.length - pos)) { + throw new IOException(); + } + System.arraycopy(data, pos, buf, off, len); + pos += len; + } + + @Override + public void reset() { + pos = 0; + } + @Override + public long length() { + return length; + } + @Override + public void seek(long offset) { + pos = (int) offset; + } + @Override + public void skip(int bytes) throws IOException { + seek(pos + bytes); + } + @Override + public boolean isEmpty() { + return pos >= length; + } + + // + + // when byte[] needed from DA, we may save few cycles and some memory giving this (otherwise unsafe) access to underlying data + @Override + public byte[] byteArray() { + return data; + } +}