Mercurial > jhg
diff src/com/tmate/hgkit/fs/DataAccess.java @ 10:382cfe9463db
Dirstate parsing. DataAccess refactored to allow reuse and control over constants
author | Artem Tikhomirov <tikhomirov.artem@gmail.com> |
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date | Sat, 25 Dec 2010 21:50:12 +0100 |
parents | |
children | 9429c7bd1920 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/com/tmate/hgkit/fs/DataAccess.java Sat Dec 25 21:50:12 2010 +0100 @@ -0,0 +1,48 @@ +/* + * Copyright (c) 2010 Artem Tikhomirov + */ +package com.tmate.hgkit.fs; + +import java.io.IOException; + +/** + * relevant parts of DataInput, non-stream nature (seek operation), explicit check for end of data. + * convenient skip (+/- bytes) + * Primary goal - effective file read, so that clients don't need to care whether to call few + * distinct getInt() or readBytes(totalForFewInts) and parse themselves instead in an attempt to optimize. + */ +public class DataAccess { + public boolean isEmpty() { + return true; + } + // absolute positioning + public void seek(long offset) throws IOException { + throw new UnsupportedOperationException(); + } + // relative positioning + public void skip(int bytes) throws IOException { + throw new UnsupportedOperationException(); + } + // shall be called once this object no longer needed + public void done() { + // no-op in this empty implementation + } + public int readInt() throws IOException { + byte[] b = new byte[4]; + readBytes(b, 0, 4); + return b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF); + } + public long readLong() throws IOException { + byte[] b = new byte[8]; + readBytes(b, 0, 8); + int i1 = b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF); + int i2 = b[4] << 24 | (b[5] & 0xFF) << 16 | (b[6] & 0xFF) << 8 | (b[7] & 0xFF); + return ((long) i1) << 32 | ((long) i2 & 0xFFFFFFFF); + } + public void readBytes(byte[] buf, int offset, int length) throws IOException { + throw new UnsupportedOperationException(); + } + public byte readByte() throws IOException { + throw new UnsupportedOperationException(); + } +} \ No newline at end of file